Why a spritz of water before grinding coffee yields better results | Hacker News Reader

Why a spritz of water before grinding coffee yields better results

arstechnica.com

346 pointsCHB0403085482262 comments

As I've seen several comments on this here - people have used spritzes of water to reduce static when grinding coffee for years, but the interesting part of this study was the finding that beyond reducing static, adding enough water prior to grinding actually reduces flow rate and increases extraction by preventing the creation of coffee clumps / aggregates.

So it confirms the anti-static properties that everyone already knew, but has interesting implications for increasing extraction without changing any other variables.

It also bears pointing out that the amount of water needed to achieve these anti-clumping effects is probably twice what people are using following existing RDT (water spraying) methods.

WDT was already super popular, so the declumping properties aren't very useful. And the static issue is mostly limited to non-traditional light roasts.

I imagine that the clumps being discussed here are much smaller and much more electrostaticly attached than a NDT can deal with.

WDT would be an extremely obvious thing to test in both the original paper as well as the follow-up videos by Hoffman/Hedrick. It is absent in all three.

Also note that Hoffman found RDT only helped in _some_ grinders. WDT also only helps with some grinders.

The clumps in question are electrically bound, so WDT likely won’t do much to break them up.

Coffee grounds aren't neodymium magnets.

No, but the clumps in question are small and are unlikely to be broken up by gentle stirring.

You are an expert on this new concept you just learned of the same day.

I did read the paper, and I am generally familiar with the physics of charged particles.

And of course I caveated everything with “likely” and “unlikely”, to hedge against misunderstanding. What else would you like me to do?

Is this the same when you try to mix coco powder with milk? You need to first use a little bit of milk or water to get it to form a sauce. After that you can easily mix it with milk

> For instance, lighter roasts have more internal moisture than darker roasts, and the latter is more prone to clumping

I suspect you might have it backwards regarding the issue being limited to non-traditional light roasts.

Lighter roasts channel more than dark roasts and also make more of a mess coming out of a grinder (more static).

It says in the linked article that darker roasts have less internal moisture content (obviously, they've been roasted longer) and therefore produce more static/clumping.

It does not say dark roasts have more static, and in the real world light roasts are much harder to brew.

I am not a coffee historian or even very knowledgable, but I thought that light roasting is the more traditional (even ancient) way of making coffee and that the roasting has gotten darker over time. Not so?

"Ancient" coffee roasting was probably very uneven. The beans were often just roasted in a skillet over a fire, not unlike toasting pine nuts. If you've ever tried toasting pine nuts on a stove, you've gotta be very careful with the heat control and keep the nuts moving frequently, or else you'll have some that are still blonde and some that are bordering on burnt.

A water spritzer (spray bottle) is one of the most useful kitchen tools. Spray your bread before toasting to improve succulence and browning -- this works best on bagels & english muffins. Spray food before microwaving to avoid drying it out. Spray frozen foods before microwaving to kick-start heating (microwaves act only on liquid water). Spray sautés to speed up heat transfer.

Your refrigerator , freezer , microwave & conventional ovens all dry things out. A big reason why leftovers are terrible is that they've lost all succulence. Also, all food needs water to cook properly . It stabilizes temps and moves heat around.

Also, air pop your popcorn and spritz it with water so low calorie Molly McCheese seasoning sticks.

this is a great general tip for salting or seasoning something dry

> microwaves act only on liquid water

This is a common misconception.

Microwave ovens heat up a lot more than just water. They also heat sugars, fats, waxes, and can even efficiently heat some types of glass.

Microwave ovens work on the principles of dielectric heating, not any form of resonance. The microwave radiation causes the molecules to rotate back and forth with the electric field to generate heat. It doesn't really have anything to do with the bonds.

Reference: https://www.physicsforums.com/threads/why-do-microwaves-only...

For practical purposes it’s a useful model.

I have to disagree. Any 'model' that implies that water has some resonant frequency that microwaves are specifically designed for is misleading to the point of uselessness.

If microwave ovens were tuned perfectly for water, then the water near the surface of foods would absorb most of the oven's energy, and not let the center of the food warm up as efficiently... essentially causing the microwave oven to heat food more like a regular oven.

AFAIK, the frequency chosen for use by microwave ovens is a balance between

* A desire for the EM energy to penetrate deeper into the food (per my 2nd paragraph above)

* A desire for the EM energy to not interfere with licensed communications bands, in the event that the oven is "leaky".

Finally: it's not very hard to explain the concept of a dipole moment, and why molecules that have one will twist in the presence of EM radiation. In fact, if you do explain this, quite often the student will come to realize that this is also true of light, which is why (A) a vintage Easy Bake Oven toy could bake a brownie with just an incandescent lightbulb, and (B) will serve to demystify microwaves as being just sub-infrared light.

> A desire for the EM energy to not interfere with licensed communications bands, in the event that the oven is "leaky"

I'm not sure how deep a desire this is, given microwaves operate at 2.45 GHz wideband, which is bang smack in the middle of 802.11n Wi-Fi and Bluetooth...

That frequency was chosen because it's not part of licensed bands, doesn't mean the band is unused. Also, microwaves have been around a lot longer than wifi and Bluetooth.

Then come up with a better model for chefs

Well, I kinda did in my last paragraph. But if you want it more ELI5:

"Some molecule shapes rotate like windmills when light or radio waves (same thing) pass close by them. Water happens to be one of those shapes, but there are others in food too, so it is not just about water. Also, there is nothing special about the frequency of microwaves to make this happen; microwave ovens use that frequency because it is considered a "free for all", and you don't have to ask the government for permission to use it for anything (cooking, bluetooth, or otherwise.) The frequency used for the microwaves does make some sense for use in a microwave oven, because that frequency tends to penetrate deeper into food than visible light does."

That's still a model -- because everything is, the map is not the territory -- but it's close enough that I think most internet pedants won't try to refine it more.

It doesn't explain why butter melts but shortening doesn't. sounds like you'll need a better model

... because shortening isn't butter. Someone else in this thread mentioned that fats have dipole moments, but that doesn't mean that all fats react with the same intensity. For any affected substance: molecular weights, crystalline structures, etc all play a role.

You aren't uniquely "ringing water's bell" with 2.45GHz

I believed this for such a long time until I learnt watching my aunt warm empty plates in the microwave.

I thought it would damage the oven like running it empty would, but now heat them like this all the time.

Thank you for being a voice in the noble task of dispelling this myth. While it is true that water strongly absorbs microwave wavelength photons, other things do as well to more or less degree. It is all determined by the absorption cross section of the stuff you stick in the microwave.

Ahh, so that's why some cups come out of the microwave with a hot handle while other cups come out with a cold handle!

And spray your cats as they attempt to abscond with your comestibles.

Can confirm, am cat ~~owner~~ family member

James Hoffmann talking about this yesterday: https://youtu.be/nLnB99VJ0HE?si=LIoZP0lwfsxvrqON

Lance made a video too, but in more detail: https://www.youtube.com/watch?v=GuqVUsMPs-U

Lance Hedrick too: https://www.youtube.com/watch?v=GuqVUsMPs-U

Yes! he also interviews Christopher Hendon one of the paper's authors.

He doesn't mention if he used WDT, which is a strange oversight.

Hoffman is a big proponent of using one, so I'd assume that he did.

He is also a content creator, so his main goal is to milk youtube views.

My understanding has been that youtube is more pet project for him, and square mile is what really pays the bills

He's done a video before on what his normal process looks like, and its always had both the water spritz and WDT, so while annoying he didn't clarify, I'd assume he's still doing WDT in these results.

My completely unscientific guess is its possible that WDT is redundant or solving a different problem, given WDT wouldn't be breaking up much of the static charges between smaller particles, just mechanically separating larger clumps that are visible to the naked eye. Still very keen to see someone rule it in or out because I personally loath WDT first thing in the morning

There is no square mile without James Hoffman the personality.

He's about the classiest content creator out there right now, so it's a bit disingenuous to attack him like that. He's like a cross of James Burke and Alton Brown, but focused on coffee. Dude is a veritable YouTube national treasure.

Being classy is part of the milk. He puts a lot of work into his youtube videos and image, it's not an attack. It's just the reality of being a content creator.

So what’s your point? ‘Person who does job X does job X’?

I can’t stand the majority of YouTubers, but James manages to come across as respectable and genuine. That’s perfectly compatible with him trying to be successful and playing the YouTube game a bit. In his position (and I don’t think he intended to become a ‘YouTuber’), you’d have to be either stupid or utterly uninterested in success not to.

I think what I am trying to say is pretty straightforward. I don't think he used WDT because he is trying to produce content and not conduct science.

I'm not here to defend Hoffmann specifically -- I don't personally know the guy -- but I also don't understand the point you're making here. He makes youtube videos, so of course he wants views. Is there some dishonesty in what he does that you'd like recognized?

It can't just be me who thinks adding moisture to the already-filthy internals of a coffee grinder is a terrible idea. Sounds like a recipe for mould growth.

I took apart my electric grinder once for cleaning and it stank of mildew even without adding water to the beans.

If you grind oily dark roasts, the oils stick around in your grinder and go rancid. That's what you're probably smelling. You just need to clean your grinder some what regularly. This isn't a problem for medium-lighter roasts and water added with RDT doesn't really have any effect in practice.

If you do this you would clean out your grinder more often I presume

Hendon, the head of this research, stated that the humidity in the grinder went as high as 70% iirc but the humidity would dissipate within a matter of seconds.

It may matter for some grinders but he stated no concerns.

The coffee will no doubt soak up any small spritz of water quickly, it's basically a desiccant. No chance mold will be able to use that water.

This kind of passion used to only be seen in items about Emacs customization!

Audiophiles too?

yeah, I have a small electric ceramic burr grinder and I dont' have any of these problems. I also have a blade grinder for when I'm in a hurry/have guests. Still no problems, I might lose 1% to static.

Direct link to the paper

https://www.cell.com/matter/pdf/S2590-2385(23)00568-4.pdf

Like others I’ve been doing this at home for years with uncooperative beans e.g. most decaf, but it’s fun to have it modeled. My highly technical method has been to stick a finger under the faucet then twizzle it around the beans in the weighing cup.

Haha, you're not alone--I do the exact same thing! I feel like too much water could affect the burrs somehow? I don't know. So I am with you! A few drops jostled around and it's good to go!

Yes, too much water on the beans can lead to water gathering on the burrs, which can lead to rust on the burrs.

I use the teaspoon method (just the handle), cover it in water and stir the beans a couple of times. Just a single data point, but I've done this for 2 years at ~2.5 shots a day with no sign of rust on the burrs. YMMV

I also do finger+faucet, but I wouldn't be surprised if it actually adds _more_ water than a single spritz.

As an alternative approach, the new Fellow Ode grinder integrates an ionizer [0] the grinds pass through for similar effect. A similar setup could be hacked into other machines or form part of a manual process for those wanting to experiment further.

[0]: https://youtu.be/B-bXctXbXFc?t=205

James Hoffman (linked above) discussed why an ionizer might not be as effective

Direct link to discussion: https://youtu.be/nLnB99VJ0HE?t=570.

Argument is the aggregate has already formed before hitting the ionizer (in the chute).

Oxo has a burr grinder with a stainless steel grind bin that supposedly discharges the static.

Many who are really into coffee know this “trick”. Still, you have to remember that there is no silver bullet that covers 100%. You can of course find beans that don’t benefit from this treatment or where things get worse, but in my experience, for my purpose, it helps with almost all beans I use regularly. Best you can do is try out for yourself and see if it helps. You and what you like is all that matters, don’t do things just because others do them.

I've got a burr grinder with a large hopper I usually keep filled with beans, how do I wet the beans in that case?

empty your hopper, store the beans in a separate container, and weigh and grind per brew.

Was just about to comment the same thing. Keep beans air-tightly stored away from the sun but not in the fridge. When making a coffee, measure only what you need.

IMHO the biggest factor is not the gear, it's the beans - I would rather "good beans and a $50 espresso machine from Aldi" than "burnt beans with a La Marzocco Linea Mini" every time.

Another thing is grinders too apparently. I watched a video once explaining why espresso machines are so expensive and they said they'd rather have a $700 espresso machine with an expensive grinder than a $4000 machine with a cheap grinder.

I often hear the priority list being

  1. Quality of beans
  2. Quality of the grinder
  3. Quality of the espresso machine

I'm not exactly sure what sets apart some grinder from another. Some say they more evenly grind the beans (similar particle sizes) but I am not sure if that is all there is to it.

A high quality grinder also minimally heats the beans as they grind - heat can change the volatility of the oils, resulting in changed flavor (and usually not for the better)

Correct, this is why people prefer burr mill grinders made of ceramic instead of metal since ceramic is more thermally insulating.

This isn't true in the high-end coffee community. No one uses ceramic burrs, and they are generally considered to produce worse coffee than other burrs.

I'd put the quality of the grinder above the quality of the beans, but that's assuming a certain minimum standard (e.g. whole beans from a supermarket brand).

If someone's using a blade grinder, then the particle size are going to be all over the place and you end up with a brew that's both over-extracted and under-extracted at the same time.

I'm not especially fussed about the espresso machine quality as I usually drink AeroPress coffee and as long as people aren't using boiling water, then it turns out fine (full immersion is a lot easier to get right than dialing in the specific grind for Espresso).

> I'm not exactly sure what sets apart some grinder from another. Some say they more evenly grind the beans (similar particle sizes) but I am not sure if that is all there is to it.

Definitely not all there is to it. There are people who are in to swapping burrs on a grinder to experiment with different flavor profiles, or to make espresso vs filter coffee. Some grinders even cater to us, such as the Niche Duo: https://www.nichecoffee.co.uk/products/niche-duo?variant=431...

Also, some people who like more traditional, chocolaty espressos prefer grinders/burrs that produce more varied particle size. People who like cleaner, "modern" espresso prefer grinders that produce the more similar particle sizes.

It's a rabbit hole.

Random: is the Niche Duo made by a US company?

Asking, as I noticed the power switch on the side: the "|" symbol was at the top, which doesn't jive with the UK's "up is off, down is on" typical switch.

Interesting, that never occurred to me. Niche are a UK company, the grinders are designed in the UK, but as I understand, made in China.

While it is true that a $4000 espresso machine will not get good results with a $20 blade grinder from the hardware store, I think you do see diminishing returns going above $1000 for burr grinders. On the other hand, spending more on the espresso machine can get you way more dials and knobs to tweak. Temperature and pressure profiling and all that.

This may not matter if you prefer medium or dark roasted coffee, but light and Nordic roasts really benefit from the extra control over temperature and pressure. With a fancy machine you can do these very long, lower pressure extractions with higher brew ratios to extract a finicky light roast which would otherwise require an impossibly fine grind that chokes a standard 9 bar machine.

> With a fancy machine you can do these very long, lower pressure extractions with higher brew ratios to extract a finicky light roast which would otherwise require[…]

Or a simple machine, like a (direct-)lever[0], which is an operator controlling a piston pushing water.

[0] like a La Pavoni, or Cremina - this video is of a europicolla owner who I think embodies well the joy that can be had matching a machine like this to the right person https://youtu.be/1BGB2i4Bu58

My next machine is going to be a lever machine for sure! Though I will say that a direct lever machine is the ultimate tradeoff of control over precision/repeatability. Spring levers give you a ton of control with more precision because you're retarding the lever to subtract from the maximum pressure of the spring rather than modulating your muscle power in real time. Unfortunately, what the simple lever machines give you in terms of pressure control, they take away in temperature control. Getting accurate, repeatable temperature shots from a La Pavoni is a bit of a black art, and the group can easily overheat, requiring you to cool it down before making coffee.

Even in the case of lever machines, you get more control if you spend more money. Take a high-end lever machine like the ACS Vesuvius Evo Levo [1]. This machine has an 11-bar dual spring group (which you can back off to your heart's content by retarding the lever) and a pump to provide selectable preinfusion between 1.5 and 5 bar. It also has 3 independently controlled (PID) heaters: 1 in the coffee boiler, 1 in the steam/service boiler, and 1 in the group itself. This allows you to do temperature profiling by, for example, setting a higher temperature in the group than in the coffee boiler, which will cause the slightly cooler water from the boiler to bring down the temperature of the group during the extraction.

[1] https://www.elcor.it/en/vesuvius-evo-leva-en/

> My next machine is going to be a lever machine for sure!

Nice - I've been a Cremina operator for the last few years, thoroughly enjoy it.

> Spring levers give you a ton of control with more precision [...]

At the expense of feedback. And to be fair and clear, most of my experience is with a direct lever, and I like it, but I'd happily have a spring lever too if I had the space.

To move things away from strictly hard-tech and measurement though, all this is also so experiential that I'm happy to keep things low-tech and manual, to degrees. My morning coffee routine is fantastically quiet for example: this doesn't (directly) affect the quality of the coffee, but I sure appreciate the experience. And the experience of being in charge of the pressure at the puck - a different way of being involved where I'm interacting with the differences in grind settings, or one bean/roast vs another...

Good luck in your lever-machine quest!

I totally appreciate the low tech approach. I think my dream machine is an Elektra MCAL!

Do you use a manual grinder as well? I’ve never used one but they seem rather clumsy to me. Maybe one of those old fashioned ones that mount firmly to the table and have a big brass crank and brass hardware with a wood case!

> Do you use a manual grinder as well?

I have, in my life - I associate them with pour-overs (V60, Chemex) for myself. In my espresso setup, I have an electric variable-speed single-dose conical burr unit. It’s naturally fairly quiet, and I run it at ~30rpm so about all I hear is bean crushing/grinding.

That sounds pretty nice! I have a Niche Zero and it's fairly unobtrusive, but still somewhat loud. At least it doesn't have any high frequency noise though.

I haven’t personally used a Niche, but have studied them a bit and think they might be a high water mark in the performance/$. A busy cafe I frequent uses them commercially (modified, for extra cooling) with success.

> I think you do see diminishing returns going above $1000 for burr grinders.

This is absolutely correct: the best "value" is a $200-300 hand grinder. Anything more than that you're adding quality of life (mostly), and sometimes even taking away from quality of coffee while increasing price.

Of course, hand grinders are generally pretty annoying to use for all your coffee needs. They are great but it's also great to use something electric.

Yes, and part of that is just preventing waste and saving work - I mean a blade grinder can get you a quantity of relatively consistent grounds after you sift them, regrind some, sift to separate, use the paper towel trick, etc., and now you have like a 30% return out of the beans you destroyed, and a pile of coffee dust and splinters. The amount of work saved by a good grinder and amount of waste reduced is worth a fair amount. I’m not sure $1000 grinder gives me commensurate value personally, but a $100-300 grinder I can travel with? That sounds quite fair even just being slightly down the coffee nerd rabbit hole. :)

> but not in the fridge

I thought that storing them in fridge will keep them fresh longer

freezer yes, fridge idk.

You can likely get more out of not keeping the beans in the “open” (large hopper) than you could get out of wetting them. Assuming good quality beans, rather freshly roasted.

If the beans are freshly roasted, it's often best to leave them two-three days to degas the CO2 from the beans.

Agree 100%, I didn’t mention this because the beans were resting for longer as mentioned by the user I replied to.

A professional roaster told me at least a week. I brought them green beans which they roasted and phoned me after a week (telling me that before that would be too soon and taking a chance) to come pick up.

It varies. I roast at home, and some beans are great the next day. Some are great the next week. The cafe I used to live next to would rest their beans for a week.

Same. I have noticed that the lighter the roast, the happier the beans are with less rest.

That being said, the best coffee I've had was Ethiopian style, roasted dark and brewed right in front of me with no rest.

I buy 5lb bags and let them sit on the counter for a week or two. Then I set aside a week’s worth for use and freeze the remainder in gallon ziplock bags with the air pressed out.

This allows me to waste less coffee and less time dialing in shots because each week’s worth will be very close in required grind setting to the previous week’s.

That's fine for a dark roast, but a lighter roast will sometimes need 2-3 weeks. Or more!

The target audience for this hack are people who carefully weigh their beans (and then put them into the empty hopper for grinding) each time they make coffee.

Damn, literal bean counters.

Busted. My scale absolutely has a units mode that is very fun and completely caters to my precision fetish.

Or at least I thought it did until I considered bean-weight variability...

It’s infuriating when you change brands. Built up a feel for how much a bean weighs and how many are needed to go from 17.9 to 18.0g? Yeah, that other bean requires five beans, and not just one.

Or removing the right sized bean to go from 18.1g to 18g

of course factoring in the age and roast too

there are even more niche products, literally called bean counters which dose whole beans to a certain weight. believe it or not they are well over $100. the deep end of coffee is both insane and expensive

I’m that target audience. It’s called single dosing. I weigh before and after because the difference depends on the quality of the grinder. Retention is the enemy of single dosing. The Niche grinder is one of the best (I’ve been through 4 grinders.) I have had mixed luck with spritzing. As the article says it only benefits beans with lower moisture but even large distributor beans vary between roasts. It takes a few shots to dial in every new batches.

I've also been very pleased with my gev 4 DF64; it was a tossup between that and the Niche Zero at the time. The retention is so small I can't even measure it.

the varia has been responding to a spritz and shake with beans before going in the hopper. i stopped measuring output its that good. Sometimes a bean or two can get stuck in the hopper.

single dose

All this research, and not a single A/B/X test. Also very common among audiophiles, even ones focused on being scientific, replacing human testing with precise instrumentation that ends up not mattering in practice.

Yes. Every time I see coffee advice like this I wonder if there's ever been an actual study on it. I don't think I can tell the difference between coffee at 92 degrees vs 99 degrees. What percent of people actually can?

https://youtube.com/watch?v=pZ-hKmz4PIY

Two people testing one brew (per temp) but interesting none the less.

The access the internet gives us to this kind of content is incredible. What a fun and interesting diversion into coffee brewing temperatures and how it might affect taste.

I think it's worth keeping in mind tweaking different parameters often yields varied levels of improvements. Going from near freezing to hot water yields very different results that you can definitely discern for example. Coarseness of the grind definitely effects results: if you run hot water over raw beans it's not great meanwhile if you could say grind to a point you broke down many molecular bonds in the bean (I'm using the term "grind" loosely here to illustrate a point), you'd lose all the nifty chemicals that you want to taste and so on.

So there's varied ways to adjust each given aspect of preparing coffee (including times of everything, the process itself, the order of the process and so on). And how you tweak each given aspect will have varying degrees of noticeable effect on the taste of the drink (some have almost none). Beans roasted 3 weeks ago probably won't be discernable from beans roasted 4 weeks ago. Beans roasted today might be discernable from those roasted a week ago, though.

Each of these aspects isn't inherently independent of one another either. Coarseness, brew time, and pressure are often very closely linked and adjusting one or the other often requires adjusting the other for desirable results.

Now while some of these sort of tweaks are tiny, combining all sorts of tiny tweaks can result in noticeable larger differences. It might not be obvious what it is because of all of the small component improvements, but the end result is something that, even slightly, is noticeably improved, which is true for about anything.

Ultimately the question is does all this effort combined yield enough improvement that's noticeable. Maybe one small improvement isn't noticeable like adjusting from 92 to 99 degrees. That combined with a series of other tweaks might yield something worth the effort though.

I know when I first started brewing espresso at home I laughed at a lot of advice thinking certain aspects of the brewing process were silly so I'd skip them or just ignore it all together. Things like weighing my beans, tweaking grind size, and so on. My first few weeks of espresso drinks were... pretty disappointing. Why can Starbucks (which in terms of espresso is often lackluster) make better espresso than me at home? As I went down the rabbit hole and adopted more silly strategies, I tasted notable improvements.

It's not just me either, I've had friends try throughout the process and it went from "thanks, that was drinkable" being nice to my not so great coffee to now people saying "wow that's really great, how do you make that, that's the best coffee I've had."

It sounds stupid until you start tweaking all these little parts. I'm not entirely scientific about it, much of it is a hit of an art and inference with science mixed in. I'm at a point now where I think no matter how many slightly improved tweaks I make, I won't be able to tell the difference and it's not worth the time.

From your example, 92 to 99 C might come down to how much energy the water actually has and how precise you can measure it. When you're approaching boiling, some parts of the water probably is boiling and made a phase transition, you're measuring an average of some other part that may not be a good sample of the whole. Those parts that are boiling may result in damaging organics in what you're brewing leading to bitter flavors you don't want, so backing off gives you some margins of error in your measurement. 7 degrees might not make too much difference if it's say 95 and 88 C (a little more time might make up for similar results) but something approaching a critical point like boiling might actually matter.

This topic was made for HN lol

(some) Programmers can't do anything without knowing everything about it

I swear. There's this implication that the idea of having cooking recipes are unscientific in that post... "Without understanding why one sautes the onions, why should I saute the onions??? Where's the peer reviewed article proving that this results in statistically significantly improved taste?"

I tend to think it's a side effect of having a curious mind. Anyone can saute onions. It's the curious that stop to ask, "Why does this taste so good and how can I do it again?" I think the best chef's are the one's that are curious in the same way.

edit: auto correct did me dirty

That's an aspect but the best chefs have mastered sauteeing onions before exploring and being curious is what I was trying to get at.

It’s time for the America’s Test Kitchen book on Coffee.

The purpose of knowing why your doing things is so that you can tweak things and understand the implications. Sauteing onions is partially good because it caramelizing some of the sugars. What other sugary things could I saute?

I rarely exactly follow a recipe so it's important to understand what effects the steps have so you can experiment with them. I've been trying to perfect cookies for years.

I can absolutely tell when onions are sauteed or not sauteed though

Otoh it reminds me of training networks. You may spend a week tuning the params and end up with no conclusion due to (1) constantly evolving training modus, (2) the inherent randomness of the process. You can’t even know if the recipes out there help you or just add to the noise. It creates a feeling that you know, but it never verbalizes into something meaningful, apart from a few fortunate coincidences.

I wonder if that’s a part our (everyone’s) inevitable future that we didn’t conceptualize yet playing on “default settings”.

As someone who is something of a coffee nerd (QM67 machine, Fiorenzato grinder w/ timer), I'll admit to balking at doing any of the more fiddly/fussy things.

But out of curiosity, how much time does the coffee nerd community spend pondering and tweaking environmental variables?

For example, ambient room temperature and relative humidity? Can't do a whole lot about pressure, short of tracking historical trends vs present air pressure and setting expectations, I suppose.

Other factors: tamping down physical, emotional irritants, such as screaming children, freshly burnt toast, headaches, etc.

And something that is adjustable but not quickly so: the (paint) colour(s) of the room. It's been something like 30 years, but ISTR hearing that different colours can affect us in subtle ways. For example, red can help stimulate the appetite. I imagine good lighting (eg, warm lighting, avoid fluorescent) is another variable.

All this to ask: do coffee nerds consider tweaking any of the above, or only those things that are in very close proximity to the grinder and espresso machine?

(Good) baristas dial in their grind size multiple times a day due to environmental changes like humidity, and I daresay the decor of a coffee shop is designed to motivate appetite. Not sure if that completely answers your questions but they've certainly been considered before.

> QM67 machine, Fiorenzato grinder w/ timer

Nice! I got a bit burnt by a Quick Mill Andreja and have always wondered if it related to the the conversion to 240v that was done on it for New Zealand. The reality never came close to the reviews.

I’m now on a Faema E-61 Legend and an orange Mazzer Robur - it’s like having a particular large traffic cone in the kitchen. Every so often I consider a more tuneable double boiler, but going back to your comment, appearances matter and and my ridiculous setup makes the coffee seem better.

> Faema E-61 Legend

I worked a bar with a 3-group. What a joy to work with.

I’m not sure it matters. For any interest or hobby, doing it my way, to my taste, is the entire point. If someone else doesn’t like it or can’t tell, that might actually be an advantage.

I don’t think I would be able to tell - I make fussy coffee, but not to this extreme.

Researchers from UC Davis Coffee Center posted a great paper about exactly this a few years ago: https://www.nature.com/articles/s41598-020-73341-4

At least the video by James Hoffman I watched yesterday (too lazy to find the link, it's somewhere else in the comments) wasn't about experience, but about objective measures: How charged were the particles, how long did it take X amount of water go through the same amount of beans? The guy in the video even said he wasn't sure if the resulting coffee was better or not, just that it slowed down extraction, which usually ends up with more chemicals in your espresso afterwards.

Are more chemicals good or bad?

Everything is a "chemical".

Generally increased extraction (i.e. getting more "coffee" into the water) is better.

Considering making coffee is extracting flavor chemicals from coffee beans into water, more chemicals would be good.

I forgot the "/s" on my comment.

Yeah I've come to expect sarcasm on Reddit but hackernews I just assume everyone's being genuine

hear hear. keep hacker news sincere

Oh, the infamous "/s" – the internet's neon sign flashing "ATTENTION: SARCASM AHEAD." Where do I even start with this? It's like we've collectively decided that the art of understanding sarcasm needed training wheels.

First off, let's talk about how it completely annihilates the fun of sarcasm. Sarcasm is like a secret handshake; it's supposed to be subtle, a little game of wit between the speaker and the listener. But no, we had to slap a big, fat "/s" at the end, just in case someone's sarcasm radar is as effective as an ashtray on a motorcycle.

And then there's the snobbishness of it all. It's like saying, "Oh dear, I better put this here because you might not grasp the advanced concept of sarcasm." It's patronizing! We're basically assuming that people online have the emotional range of a teaspoon and can't catch a sarcastic comment unless it's gift-wrapped with a "/s".

But wait, it gets better. The safety of "/s" makes a padded playground look like an extreme sports event. It's like we're afraid of a little scrape or bruise from a misunderstood joke. Remember when playgrounds were made of concrete and we survived? Now, it's all about safety first, even in our online conversations. "Watch out, don't hurt yourself on that sharp wit!"

And as we progress down this ridiculous road, let's envision a world where everything is as blatantly obvious as sarcasm with a "/s" tag. Imagine going to a comedy show where the comedian has to pause and explain each joke. "And that, ladies and gentlemen, was a joke about marriage. You can laugh now." Or picture reading a book where every metaphor is followed by an explanation. "The curtains were blue, which symbolizes the character's deep sadness, in case you didn't catch that."

We could even take it further. How about emotional cue cards for everyday conversations? "I'm about to tell a joke – please prepare to laugh" or "Warning: sarcasm in 3, 2, 1..." The possibilities are endless in our brave new world of over-explained humor.

In the spirit of this absurdity, let's just put disclaimers on everything. "Warning: This rant may contain traces of hyperbole and a pinch of irony. Please consume responsibly." And don't forget, if you didn't find this funny, it's probably because I didn't put a "/s" at the end. My bad.

Perhaps we need a /a for AI content, as well?

Sarcasm itself is not banned here. The community pushes back against sarcasm because it is often associated with poor quality comments. I've quoted some comments by dang about sarcasm with links to his source comment - it helps to read his well-thought-out opinions within their context.

  The guidelines don't rule out sarcasm. They ask for comments to be civil and substantive. The Venn diagram of those things may not have a lot of common area but there's definitely some. Just don't ask me to specify what it is—that's probably too hard.[1]

The community here avoids sarcasm not for the reasons you so condescendingly note, but because sarcasm tends to reduce discussion quality.

  Readers here recognize sarcasm, but they also recognize what happens to a web forum where it is allowed to proliferate.

  We don't have any problem with satire and sarcasm as such, but on a large public forum like HN, with everything a mile wide and an inch deep, they are nearly always associated with really low-quality discussion.[2]

The logic is similar to why jokes are discouraged[3].

  I've often wondered why jabs, swipes and sarcasm are so corrosive on HN when anyone who knows about the history of discourse knows what a lively role they have played. [The lack of sarcasm] makes the discourse a little more bland, but the alternative is not lively exchanges of high wit, it's YouTube comments.[4]

  I think sarcasm is more of a problem on HN than lame humor is. Humor doesn't always succeed, but at least it's intended to make others feel good. (Think "good humor".) Sarcasm is only marginally related to humor. It's really about scorn. Sarcasm is verbal bile. It feels good to let it out, but it acidifies the environment. It feels like you're being smart[5]

Like you, I love sarcasm (New Zealander's tend to slather it on) and when used well it is a often a subtle compliment to the receiver. Over the years I have learned to tone my sarcasm down because I tended not to use it helpfully and respectfully.

Note that Dang seems to personally like to use sarcasm[6].

[1] https://news.ycombinator.com/item?id=10411394

[2] https://news.ycombinator.com/item?id=18506429

[3] https://news.ycombinator.com/item?id=18284457

[4] https://news.ycombinator.com/item?id=9378899

[5] https://news.ycombinator.com/item?id=9342526

[6] https://news.ycombinator.com/item?id=7544169

Note that my comment is directed specifically at /s and not at sarcasm in general. I understand very well that given the diversity of opinions on internet it can be challenging to tell it appart. So I agree that in many case one should abstain. But if you go ahead and still use it, please, by all mean, don't botch it. Better to double down and make it obvious or ridiculous than this silliness.

You seem to be really upset about this, and I feel for you how much you will suffer over the years when people don’t do things the way you think they should.

I wonder if, thanks to Reddit’s karma economy, the usage of /s is some kind of learned behavior that acts as hedge against downvotes. Did people use /s as much or at all back in the days of forums or other platforms where the visibility of a person’s content didn’t correlate with upvotes?

It’s no different than emojis. It’s there to bridge the gap between in-person spoken communication and written communication.

Some people hate emojis too.

It doesn’t seem like you’ve considered that people do a better job discerning sarcasm in person than via the written word. In person, you can judge tone of voice and facial expressions. I once heaped praise on someone by email, and they became really upset, because they thought the email was dripping with sarcasm.

Including the “/s” helps to ensure that one is understood. To me, that seems more important than whatever it is you think has been lost.

No, more chemicals isn't necessarily what you want.

Coffee beans contain diterpenes, which have been shown to increase cholesterol. Paper filters significantly reduce the quantity of diterpenes in the end product.

Depends on which chemicals and what your taste is. I think the main idea of espresso is that by that method you get more of the tasty chemicals and less of the bitter chemicals compared to (say) a French press (aka cafetiere). Since this is just a few seconds longer, you'd hope that the resulting brew would be less watery and have more of the "good" chemicals without getting the "bitter" chemicals. But as OP said, without an A/B/X test, you can't really say for sure.

"Extraction yield" may be a good thing, but that hypothesis goes untested.

Distilling, one wants to control extraction yield to isolate the best flavors. Done carefully, one makes armagnac. Maximizing extraction yield makes moonshine.

It's a hobby for people with a particular personality type. Tight control of variables and precision is part of the enjoyment of the hobby. It's the same as obsessing over whether your model train engines have the precise same badges and labelling that existed in real life.

Women do yoga. Men do this. Or obsessively sharpen knives or practice their golf swing until it's robotically consistent.

Think of it as a form of meditation for a particular type of person.

As much as I agree with the sentiment of your comment, the part "Women do yoga" is quite reductive and can easily be interpreted as "women can't be that type of person" which I disagree with.

Hobbies are often heavily gendered.

You don't see many men doing knitting but it's also a very careful technical thing. And it's full of strong opinions just like coffee or golf or whatever.

It's just saying it out loud isn't very polite unless you're a comedian or jesting, because people will automatically read into it as a moral or intelligence judgement.

But otherwise I think it's pretty obvious men typically go very hard into their new hobbies, almost obsessively. Additionally, they often do it for short periods before finding a new one to jump into next month and then suddenly they forgot about coffee and are learning how speakers work.

Generalizations are Generalizations, that's how they work.

> Hobbies are often heavily gendered.

> But otherwise I think it's pretty obvious men typically go very hard into their new hobbies

I'm a man. The other day I wanted to see if there was a way to fix one of my daughter's Barbie dolls and ended up in a huge rabbit hole of Barbie dolls collectors, which you can peruse (at your own risk) in r/Barbie, YouTube and others. These are (mostly) grown women obsessing about their dolls collections, swapping heads and bodies, re-rooting hair, fixing damaged hair, sewing their own custom clothes, asking questions about "color charts" (to match parts from different dolls), re-painting face details from scratch and consulting authoritative databases that list every Barbie head by year and detail which bodies use it. Some tattoo their dolls. One had replicated the main characters from Cyberpunk 2077, meaning she was also a cyberpunk and videogame nerd.

There are some men there too, but I grant you it's mostly women. Their attention to detail and obsession with their hobby rivals model train enthusiasts.

I think in this day and age there's a hobby for anything, and women are not only not excluded from this trend, but tend to be passionate about it.

I've also found women who are nerds about coffee, mind you. Many have YouTube channels about this.

A friend of mine just discovered book nook kits. He's jumped in pretty hard, with multiple kits and custom 3d printing various greebles for his new models/dioramas.

Example book nook: https://boardgamegeek.com/image/7900081/scotte

That community is about 95% women. Book nooks are adjacent, hobbywise, to dollhouses, which may explain it.

That's quite lovely, how marvellous

> interpreted as "women can't be that type of person" which I disagree with.

Women can be that type of person, for sure, but statistically they tend not to be, and on a colloquial forum we write colloquially and interpret intent broadly and generously, the best to facilitate productive dialogue and avoid descending into semantic argumentation.

I'm all good with supporting people of all genders to do whatever they choose, but this comment seems to be needlessly pedantic, and breaks an HN guideline:

- Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.

We don't need to be so literal and inflexible about everything. Even with modern sensibilities, we're adults here and we're all capable of reading a comment like that and understanding that the author doesn't actually mean that no or even few women can be obsessive about coffee/knives/audio systems, or that no/few men can do yoga.

(FTR I'm sure I'm not alone here in being a male who does yoga and can also be obsessive about things like audio quality.)

> Women do yoga. Men do this.

I agree that it's for a certain personality type (I myself am one of the obsessive espresso people). But it needn't be gendered.

> it needn't be gendered.

But it is

Let me make this more explicit, since you clearly didn't get the hint. It's not gendered, you are making it gendered.

I'm just stating a fact that Yoga, by and large, is an activity where female participation massively outnumbers male participation.

You're right that it doesn't _have to_ be gendered but it is - observably so - gendered.

You could also well make an argument that the female body structure lends itself better to flexibility than the male body, due to that elastin and hormones and stuff, so it could well be said that there's a gender-bias built in from the ground up.

It seems people are focused on the “women” bit not the more interesting “meditation” bit, which to me rings true — these hobbies bring me mindfulness and contemplation.

Also to the extent that “kindergarten teachers are women”, women do yoga. 3 to 1 participation vs men, and the pop culture face of the hobby.

Not really. It's just that the people obsessing over variables are the same ones making YouTube videos.

I'm a technically minded person (and a guy) and I take no joy in being hyper-precise with my coffee making, yet enjoy coffee a lot. Good beans that I grind myself in a sub $30 grinder, measured by eye and brewed in the drip-over is better than most coffee I encounter and consistent enough. I don't see much point in getting fancier with it. I have other hobbies to nerd out about with better "returns" on the obsessing. Side note: yoga is pretty enjoyable, you should give it a go, maybe.

I'm a bit of a non-conformist generally, so maybe my view is skewed, but I think a big part of the "X people like Y" pattern you see and refer to is that many people just aren't practiced in trusting their own feelings and senses to develop their own preferences: they see people like themselves, and they align, and conform, often unwittingly. They join the [let's say] goth clique in high school, and then come to like mostly the same things as the rest of their clique, not only by nature or coincidence, but by a mostly subconscious desire to belong. It applies to things like gender and profession, too.

I did the obsessive coffee quest about two decades ago, and in the intervening time simplified my process down to just grind consistency and an immersion pour over (the Clever). The output process is ridiculously consistent and high quality.

I've taken this simplification bent to its logical conclusion and no longer drink coffee. Best repo is the null repo, simplest cup of coffee is the one you never brew.

I know the "yoga" comment seems reductive, but the actual stats: 4x as many women as men do yoga.

https://www.statista.com/chart/27653/yoga-men-and-women-by-c...

> Women do yoga.

Off-topic warning: Man here, in "late middle age." For several years I've been accompanying my wife to yoga classes 2-3x/week at our local YMCA.* I'm not especially fond of it, but it seems to have been good for my balance and flexibility; I don't feel the way I'd always imagined my age would feel. (Diet and lifestyle also help, and I've long done and still do plenty of other workouts, incl. a fair amount of running and swimming in the past.) The yoga classes typically are about 1/3 men, mostly in my age bracket.

* For years, my wife tried unsuccessfully to get me to come with her to yoga classes. Then one day I heard a tone in her voice that she really meant it and would be upset if I didn't comply. I've been doing yoga ever since ....

if the input and output are humans, what do you imagine a nonhuman test gains you?

You should not put humans in your espresso machine.

Indeed, they tend to clog it.

The clog is only the beginning! If the person is Dutch that is.

I've heard you get better results if you spritz them.

It is already a common industry trick, so there’s no need to establish that people prefer it. Whether or not it produces somehow objectively better espresso, it is still possible to study the mechanism behind the reduced clumping and to quantify the static charge changes.

This reminds me of visiting a locally-famous coffee shop where the barista won some international competition for best-tasting coffee. The line was long, but I was told it was well worth the wait.

He has this whole process to make a pour over: carefully weigh the beans, three precision kettles set to different temperatures, carefully pouring, weighing, timing the water from each kettle—he even discards half of the first extraction. All of this is because different compounds are extracted at different rates based on temperature, and the first one is considered an off-flavor if it’s too strong but enjoyable nuance in the right amount. The line was long because the brewing process was long, and he could only focus on one cup at a time.

In the end, by the time the freshly-brewed cup got to me, it was lukewarm disappointment. It might have been the best-tasting coffee ever if hot, but it needed an Ember.

https://open.substack.com/pub/albertcory50/p/google-busts-a-...

On that topic: Jerry and I and some other Googlers did test one variable, at least.

You might find it interesting that suggestions are shifting. It largely depends on the roast level, darker roasts should have a fresher date. However there are now some "Nordic light" roasters that specifically recommended 2 or 3 months of resting for the coffee. The flavor does change over that period, not really getting stale but some flavors deepen and improve.

> suggestions are shifting.

what does that mean?

Sorry I just meant that I see people online suggesting longer resting periods, especially for lighter roasts.

on this whole topic, there are 999 posts theorizing about what makes better coffee for every one about "can you taste it?"

It IS hard to organize a tasting, and then what have you proved? But the evidence adds up, eventually.

I haven't read the paper, but James Hoffman and others regularly do blind tasting with 3 cups, testing things like extraction. In the case of extraction, for example, they'll measure extraction with precision scales, then have 2 cups at one level (either the "optimal" extraction or slightly below/above) and the third cup at the other level. They don't know which is the outlier, but they're to guess. They seem to be very open when they're not sure or the difference to them is marginal. They try to control variables like temperature.

I don't know if they make sure the person putting the cups down doesn't know which is which.

Extraction yield differences at the levels shown in the paper is no small thing (8.2% to 8.9% TDS). And I am sure an experienced coffee taster will spot the difference instantly. There is also the practical aspect of making less of a mess out of your grinder, as charged coffee particles tend to go where you don't want when to go and stick there.

But you can think of it differently and see it as a way to have a cup that is just as good but using less coffee, because it is better extracted. Less waste is a good thing, for the environment, for the coffee brewing industry, and for you.

> There is also the practical aspect of making less of a mess out of your grinder, as charged coffee particles tend to go where you don't want when to go and stick there.

I tried the RDT once. I find absolutely nothing practical about it. The mistake is trying to grind straight into the basket. I started grinding into a separate large cylindrical receptacle (a.k.a. a Tall Cup) that I can fit directly under the spout and catch all the grindings with.

Wait 10 seconds for the static to settle.. bang the cup three times on the counter... then pour the grindings into the basket. Manages most of the static, nearly all of the mess, and makes the whole operation so much easier and efficient.

The espresso space is filled with people who are _content_ to spend 95% of the effort chasing the last 5% of quality. I cannot truck with those people.

- According to James Hoffmann video on the subject, when he tried to replicate the results, the choice of grinder had a big impact. In the paper, they used a Mahlkönig EK43, a very popular grinder in cafés, less so at home.

- Your routine with the cup can count as "high effort", and if spraying a bit of water on the beans lets you avoid that extra step, it may actually be an improvement in terms of effort.

In the end, I think it all comes down to your grinder and tolerance for effort. Some people have espresso as a ritual, and as far as rituals go, that one is harmless and results in a good cup of coffee, so I am all for it. Not my thing either though, and while I like playing a bit from time to time just to see what can be done with some effort, my routine is as simple as it can get. Note that I happen to have a doser grinder, which is usually not ideal in a home setting, but it does a good job with the static, essentially what you are doing but as built-in feature of the grinder.

I have the Bezzera BB005 grinder. It's a reasonable choice for someone unwilling to spend $3000 on a grinder for home.

I actually like to use the bean hopper, and to use the RDT, you have to keep the hopper empty and fill on each use so you can actually spray the beans that are about to be ground.

With the cup, I can load up the hopper for the entire day, then just grind. It's significantly less effort. Particularly when it comes to weighing the shot into the basket, I can just tare out the weight of the cup, and I don't have to mess around trying to balance a basket on a scale.

When I watch most of these "youtube experts" push out a cup of espresso it drives me up the wall how much effort they waste. In particular, because to them, it seems like the more effort wasted the "better" the routine is. It needlessly scares amateurs away from learning how to make their own espresso.

I thought I'd share I finally tried this today, on a fairly low end grinder that clumps because of mechanical means, not just static means. After doing a little WDT to break up the larger clumps, I noticed I only had to do a very short WDT before the grounds looked ready. I noticed the shot took about 8 seconds longer than normal before I reached the target weight. Super cool!

edit: to make this slightly more scientific: My spritzing was 0.5g. Hoffmans video seems to indicate his bottle takes four sprays to hit 0.5g, my cheap nasty bottle did it in two sprays. Definitely worth measuring with a 0.1g scale if you're going to try this, as 0.1 appears to reduce chaff on your grinder, but around 0.4 onwards was needed for this brewing outcome

I generally don't follow recipes and rules although I do read them - but always experiment during cooking. Coffee is one of those over the last 40+ years.

After many iterations (filter, mocha pot, simple espresso), I have arrived at a French press for my morning coffee at home - I grind coffee reasonable fine and onto the pot while getting water ready in a electric heater. I add just under 3 tablespoons of water and then slow stir for a good 2 to 3 mins. Then add remaining water. After a couple of mins, it is a really smooth coffee in a mug and ready for the scrum call.

I do the same for tea as well - tea leaves, black as I prefer with milk, stir, wait and a relaxing cup at night.

I found the stirring to be the most useful - mentally a few mins of inconsequential living, and then with a good cup

I use a similar method and the stirring / first drench (the “bloom” - 45-60sec sufficient in my experience) is important for letting all the air come out of the grounds so that they can dissolve in the rest of the water and not float on the top where the extraction will be suboptimal

If you wanna save time, you can skip the bloom (water and stir) since it doesn't really have an effect for immersion brews like the french press.

I suspect adding a small amount of water has a similar effect to letting the water cool to 95C - I certainly assume the heat capacity of "a little bit" of water is less than a full press.

So, sure, skip the water&stir - but be mindful of the temperature.

I'm still a drip man but after about 20 years of trying all kinds of coffee, french press is still what I fall back to when I'm not in a hurry and want just a smooth flavorful coffee. I always grind my coffee and use within a day or two, nothing smells as nice as fresh ground.

Ask HN: To anybody who has tried this, does it gum up the grinder?

The opposite. It helps with retention.

Nope. I use a little spray every time I grind. Also used to wet a fingertip and stir the beans with it for the same effect. I'm not grinding for espresso, but reducing static is nice for cleanliness and minimizing grind retention. Tons of coffee nerds have been using this technique for many years now, never heard of it causing grinder issues.

Business partner / coffee expert was huge into the online barista community and knew about this method for years. We did it with our commercial grinder and it worked great to reduce the amount of cleaning the grinder needed

The method in this paper is different than most existing RDT applications since achieving the best results requires much more water than anyone was previously suggesting. The heuristic that James Hoffman has espoused is 3-4 spritzes of water per 18g of coffee. Obviously this depends on the spritzer you use, but it’s much more water than people have used before so questions about that effect are valid. The paper addresses these concerns somewhat by measuring humidity in the grind chamber, and they found that it dropped to ambient on the order of a minute after grinding finished.

Yes I had some beans stuck in the grinder after trying the technique, I guess you could try to push them in or remove them somehow but it makes the whole process take more time and laborious to make sure you dont end up grinding old rancid beans the next time around

He says "just a spritz" and it is true that just one spritz does help, but in the paper there was quite a bit of water applied - probably more like 3-4 spritz of water.

Spritzes? :-)

I'm curious about how to add this to my coffee brewing process. Is there an optimal amount of water for a given weight of beans? Does it need to be a "spritz" rather than a "drop"? As in should I ideally find a spray bottle that nicely atomizes the water to apply it? Or would it be better to add the water to the beans, stir, then add them to my grinder?

The main known benefit is the reduced static electricity which reduced the amount of coffee sticking in and onto the grinder.

The paper observes some difference in espresso brewing time in some grinder/brewer combinations, but this does not replicate well and wasn't investigated in regards to taste.

In my experience only dark roasts have the static electricity problem, and since I prefer very lightly roasted beans this doesn't usually come up. But it is truly very annoying.

Alleged "medium roast" can have this problem as well though. A few drops of water into 16 grams of beans kills the static and very little sticks to the grinder.

It depends a lot on the grinder. On some of my grinders this is true, on others its "bad to awful" from the light to dark roast categories.

Also remember, one man's "light roast" is another's dark roast. I consider light something like nordic (and lighter) - what others consider light I would put well past "medium" but before "oily" - I consider "dark" right before beans start to get oily.

You can use a wet spoon handle

I use a chopstick dipped in water.

If you watch espresso enthusiasts on YouTube or whatever, they’ll have a little spray bottle that they spray the beans with before grinding. The spray nozzle has a short travel. It looks like a sample size or something, very small bottle.

I don't think there is one right answer - for a normal morning brew (15-20g of beans) 2 spritz out of one of those small spray bottles should be in range. Two spritz, then shake the beans up (like in a cup), and grind as normal. You may notice some changes in your brewing method: faster or slower brews. Adjust to taste.

Are we talking metric spritzes or imperial spritzes here?

The paper provides the exact mass of water used, however nobody has a kitchen scale measuring to those tolerances.

I've used one of these types of sprayers for a couple years: https://www.amazon.com/dp/B08X7HLJP7

I originally did it because my hand burr grinder would end up with ground coffee stuck inside due to the static electricity. One, quick, half-spray is all that's needed. Lately I also use the spritzer to dampen the filter and the grounds while I wait for my water to heat up.

This is also known as a "bloom" if you do it before the full immersion. Helps the CO2 boil off before you load the rest of the water in, which keeps the grounds from clumping at the top and not fully extracting.

I have to wonder how much this static electricity is in an actual coffee shop... I'd think that the machines would be legally required to be electrically earth-grounded. Wouldn't this remove the static charge as the coffee is physically ground? And, even if the coffee particles are charged after physical grinding, wouldn't water flowing through them in the espresso maker also electrically ground them, thus removing the charge?

I consult for a specialty coffee shop, and in my experience the electrical ground of the machine has no impact on static generation - I doubt the burrs themselves are grounded. The amount of static you get very much depends on the specific grinder you use. Our large-batch shop grinder creates massive amounts of static and requires water to be added to not end up with a mess, while our espresso grinders tend to generate less.

To your second point, one of the fascinating things about this study is that the static charge during the grinding process causes the coffee to clump - that means that by the time the water hits the coffee puck it is too late to avoid the static-induced clumping.

On average, what comes out of the grinder is electrically neutral, so there is no more point in grounding the grinder more than for any other electrical device.

The problem is at the particle (coffee grind) level, some are positively charged, others are negatively charged. The result is that if two particles of the same charge come close together, both will shoot out in opposite direction, and that direction is not necessarily where your basket is, and it will make a mess. If however, two particles of opposite charge come close together, they will stick together and neutralize, but by doing so, they will form a clump that may cause uneven extraction.

The idea with spraying the beans with water is to prevent static buildup before particles have a chance to form clumps or make a mess.

I've never noticed static is a problem, but I use a $15 blade grinder and a $15 French press.

There is a burr grinder that never has a problem with static cling so does not require the spritz of water: the KitchenAid KCG8433DG Burr Grinder (the last two letters refer to the colour of the body, so mine is Dark Gray). The grinding mechanism is conical and shockingly quiet, unlike the typical flat disk burr grinders I've had over the years from Braun, De'Longhi, Black+Decker, and Cuisinart, with all their static mess and irritating loudness. The conical nature of the grinding mechanism seems to force the grounds downward quickly and directly into the lower hopper with no static or mess. The lower hopper is cylindrical, meaning that the contents pour into my coffee maker's basket so much more cleanly than from the rectangular or oddly shaped hoppers from the competitors I've mentioned.

https://www.youtube.com/watch?v=hpjGfpN4y7w

Conical burr grinders are much better. Kitchen aid isn't the only brand. I have a brazata encore that works very well and there's a good modding community for it as well. For example the burrs can be upgraded fairly easily which is typically needed if you want an expresso grind.

I'd never heard of that Brazata Encore, not that I'm in the market anymore. Good to know though. The KitchenAid allows removal of the top ring in the conical grinder, allowing ultra-coarse grinds. I've never had to do that because I find that the coarsest grind is already great for my French Press.

While the encore is a good machine, pretty much everyone is agreeing that flat burrs provide a better consistency than conical

That is not at all what I have found, but who am I to argue with "everyone", heh heh.

Fair enough. I prefer Americano via the aero press so conical is better for me. I think espresso is better when made with flat grinders. Tomato tomahto... Trying both, I prefer conical.

As a couple people pointed out:

Human taste testing is the only way, if you want to up your game. I just published a paper on this on HN (sorry, one arm's in a sling, so don't ask for a link).

If what you want is Science, then this is great; don't get me wrong.

Most of these new techniques (spritz before grinding, pre-infusion, puck screens) don't help at all with traditional dark espresso roasts. If you aren't brewing light roasts, then you don't need to worry about this.

Doesn't getting any moisture in the grinder cause the grinder to dull faster?

I think this is a relevant question for those of us who are… doing this stuff at home and not expecting total perfection, haha. If my coffee is only slightly better, I’d rather not wear out my grinder.

But, coffee beans already have some moisture in them, so I suspect the grinders can handle a little moisture. Just speculation though.

The study looked at the effects of the moisture on the grinder. They noticed a slight increase in humidity within the grind chamber that dissipated within a few minutes. Not something I’d worry about.

What if you grounded the blades and inner areas? Would static be eliminated?

I tested that once on an old Black+Decker burr grinder by changing the OEM ungrounded plug to a grounded one. The superstructure was mostly plastic so grounding the whole unit wasn't possible, so I attached a length of grounded bare copper wire and ran it into the hopper after drilling a tiny hole (which made the polystyrene crack and require gluing). The results were not as I hoped: the bare wire thankfully seemed to conduct a lot of the static, but that meant the copper wire was coated in the grounds. The end result was that empthing the hopper was pretty well just as messy as without grounding.

Your results may/will vary, and I never attempted other grinder grounding ideas. I bought a KitchenAid KCG8433DG, which does not have any issues with static.

I'd be interested in hearing from folks that live in more humid climes--is this as much of an issue there, versus, say, Arizona? Or is the static buildup consistent regardless of ambient moisture?

Lived in the Appalachians and Ozarks, both are fairly humid locales. Coffee is the most static substance on the face of the earth.

I just spritzed my headphones and the audio quality is definitely better

The article is specifically about espresso but the title here suggest it works for any kind of coffee. Does this apply to traditional slow brew coffee too?

This is good to know.

I usually stir the fresh grinds with a metal fork which seems help remove static charge.

It seems like the static problem gets worse with darker roasts (in my experience).

The darker roasts part is mentioned in the article too! It's because darker roasts have less internal water content to begin with since they have typically been roasted longer

Just tried this trick, using a bottle spray on some beans in the hopper before grinding. And this was before I read this article, very timely!

I’d love to see some coffee snobs do ABX tests of their voodoo coffee vs. something from Walmart

it's called cupping and we do it regularly. it's extremely easy to detect differences between coffees when tasting side by side. I roast my own at home, doing two batches of different coffees at a time, and try to compare them with each other as well as my previous batches. using grocery store coffee as a baseline is actually recommended as well.

I highly recommend doing a cupping sometime, it's great for learning what you like, you may discover something.

What do you use/ how do you 'clean' your mouth between varieties? Water, I'd guess....?

I rinse my spoon in water but i don't do anything else.

here's the full protocol if you're interested! I highly recommend doing it sometime, just get a few different coffees, ideally with a roast date < 4 weeks old. "best by" dates can be like 6 months post roast.

the rating system is for professionals, but doing each tasting focusing on specifics like acidity, bitterness, body, etc is definitely valuable!

https://sca.coffee/research/protocols-best-practices

or if you prefer a video, James Hoffmann has a cupping walkthrough.

https://youtu.be/cSEgP4VNynQ?si=JM8DBxMUEaxyh5HZ

But as they point out residual moisture varies by roast, bean, time since roasting, storage, etc.

I'd be worried if there's an increased risk of mold growth.

I've been doing this for years and haven't seen any evidence of mold, even in more humid summer months.

You're worried mold is going to grow in the 5 minutes between grinding and brewing?

More like in the 24*60 - 5 minutes between brewing and grinding again the next day. In all seriousness: it can takes surprisingly little time for ground wet coffee to form mold. Think 48h range especially when it's relatively hot.

Are we talking a metric spritz or an imperial spritz?

All science is performed in metric, and as this is ars technica you know it is not science, and therefore done in imperial. qed

A then B, ~A then ~B?

All computer science is performed in valid proofs, and as this is Hackernews you know it is not computer science, and therefore done in fallacies. qed

Campari is the best and only spritz

My local coffee shop does none of the fancy stuff bar you see in vids. Bar grinding beans. No weighing or spraying or stirring.

Tastes amazing.

That's great - you're correct in realizing some of these things aren't really suitable for a "production" env, versus (e.g.) a home enthusiast, which might essentially be a lab environment. There's space for both of them.

Most high-end burr grinders have settings that allow you to adjust how much coffee comes out for a single dose. The machines also can be tuned to deliver a specific output for a given grind and dose. Given this, it's likely that the barista is still weighing inputs and outputs, even if you don't see them use a scale while you're there.

I would hope so when they're using espresso machines worth $10k+ more than mine

Halfway down the article it mentions all this testing is with Starbucks coffee beans. Yuk!

So that stupid pin brush people invested in to mix the grinds is now obsolete

WDT? I don’t think that is needed unless you have a crappy grinder.

WDT basically always gives a boost in extraction, regardless of grinder. I haven't seen anyone recommend against it. You can get by without it but if you can put up with the minor hassle you should do it.

why am I suddenly seeing more posts about coffee & brewing. I can swear I did not search about it or click ads, is anybody else experiencing this?

I can't believe they milked an academic paper out of this.

I know people who have done this for years.

Eh, most journals are mostly digital nowadays, it isn’t as if they are going to run out of room.

The methods might be interesting, and if nothing else it seems like accessible material. If it is well written it could be a nice quirky paper to stick in a senior year undergrad course…

And, that people already do it doesn’t mean it is unpublishable. It is good to figure out why common behaviors work.

Especially because people didn't know ALL the effects. This is not just about static, but also how it impacts shots.

You might be interested in James Hoffman's opinion of the paper, a coffee wonk who has been using the RDT for a long time, but found a lot to learn from the paper:

https://youtu.be/nLnB99VJ0HE?si=1Pc47qo94ZxbTlZq

Most times you will not reach this stage to make a difference, most of the adjustment is in the grind size, dose, and temp pressure. This is just gonna add another variable to where things can go wrong. Leave it to barista championship to do this

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