Coffee with a splash of physics: how to make the most out of your brew
physicsworld.com
physicsworld.com
I do like the advice grind coarser and extract with more water -- that's made my V60 coffee quality fairly consistent, but everyone's mileage will vary based on how they like their coffee and the roast profile.
There are so many other variables that didn't get a mention: Coffee varietal
Water hardness (and even which other ions are present in the water) and its effects on acids and other compounds that highlight certain varietal's defining characteristics.
Vessel temperatures.
The filters used (materials, paper thinness).
Pouring patterns (circular, concentric, hypotrochoid, more?)
The filter shape and material.
Even the grinder used conical vs. flat burrs and high RPMs vs. low RPMs creates palpable flavor profile differences.
The rabbit hole goes deep and continues to expand.
Brewing coffee and listening to music becomes much more of a ritual process, than a task grounded in reason, and the end result is unlikely to pass a double blind test.
"Let people enjoy things!"
Yes, yes. But if you're buying audiophile fuses or power cables, or you're using TDS meters, a 5000$ grinder or if your kettle has an app, in the words of one of the great thinkers of our time: it's time to stop.
Buy a reasonably priced burr grinder, an Aeropress or decent pour-over, and some nice quality coffee, and you will be drinking better coffee than 95% of people.
...and I stopped. I didn't get to the $5000 grinder stage, but the annual costs of coffee were alarming. I went for black tea instead, served in insulated mugs and flasks. Originally the plan was to just have coffee as a treat when meeting friends in coffee serving establishments, however, that doesn't happen. I buy coffee for whomever I am with and keep my flask below the table, still spending, but not consuming.
For all the thousands of coffee cups had, I can't think of any contenders for the 'greatest one'. Hence, despite the rituals and expense, it was all forgettable. Yet I was so insistent on getting my fix.
After some time away, I can see coffee for what it is. There are too many children in the south doing things with coffee beans for grown adults in the north. Shouldn't they be in school? Tea isn't quite the same, picking leaves is different, even though I haven't done it myself, there are worse jobs to have.
The paraphernalia aspect is also something I now reject. Fancy coffee machines and even the Aeropress just says 'it's time to stop'.
Similarly, the elevation of the job of 'coffee maker' to the grand role of 'barista' irks me. We place the 'barista' up there with the greatest composers, rocket surgeons and rock gods. Sure, a 'barista' might be your greatest ever hero if all you do is drink coffee and the only work in your country is in customer service, but I don't see the 'barista' job as worthy of a pedestal, particularly in countries where the pay comes primarily from tips.
Then there is everything else, the take-out cup, the animal excretions, the added sugar. My comfort drink of old, a frothy latte in a plastic lined paper cup, is not what my body really needed. You have got the stimulant from the caffeine, and you don't need stimulants if you get all your nutrients. The mix of milk and sugar would be considered wrong by a true coffee drinker, regardless, you have got diabetes in a cup right there, with saturated fats and 'free' sugars. You are just asking for arteries to be blocked and for dementia to happen.
Whether aware of it or not, there is status with beverages. We all want to eat from the king's table, not the animal's stable. I can't say I impressed anyone with coffee, whether making it or drinking it. One lesson learned, make coffee for people and it just becomes expected. Being a keen coffee drinker doesn't make you cool. I am not saying that drinking just black tea makes one cool, but, for people that are coffee dependent, with other beverages consumed, the idea of drinking just tea, with no additives, is crazy talk.
Each to their own, but I am seeing so many upsides to 'tea only' that I see no reason to change, apart from tannin on teeth, which can be a problem if also consuming lots of colourful spices. The money aspect is an invisible upside, it is not like I get a lump sum for all that money saved, even though it is thousands a year. The lack of waste is definitely really good, since I don't have glass jars, single use cups, plastic milk cartons and more coffee-related trash to dispose off. Tea is actually valuable in the second life for composting reasons.
Anyway, having been away from coffee for quite a few years, I still appreciate the smell, but I am not tempted. To me the obsession with coffee is amusing, much like seeing what some cats will do with catnip, it just seems a bit unnecessary. My taste buds have adapted, I moved on.
Satire of such package labels, but unfortunately true for some coffee devotees.
I don't think there's any ethical consumption of industrial scale agriculture that cannot be mechanized, because we don't want to pay the real costs.
"I just overhauled a la marzocco sitting in my kitchen. People often inquire about whether it's worth buying an espresso machine for the home, or if it's a good investment as a coffee connoisseur.
My reply is always that it was the best money I've ever spent and the worst investment I've ever made. It's a lifestyle choice, and a questionable one at that. But one I'd make again every time given the opportunity."
I'm using an Aeropress and an 1ZPresso handgrinder. I found that it helped a lot to do things exactly the same way each time. It reduced variability and made it easier to adjust a parameter like grind size. In particular I found stirring to be a really finicky parameter with a potentially large effect. If I stirred vigorously without changing anything else, the coffee got noticeably bitter. I switched to not stirring at all, it's mixed plenty just by pouring the water. Makes the workflow easier and reduces variability.
So while I think there's plenty of ritual around coffee that has no real effect, I suspect the value lies in keeping to exactly the same method and performing all steps the same way each time.
The person I really want to hear from about brewing coffee is a chef. Someone who probably doesn't have the time to nerd-out to this degree, has great taste, sees the big picture and is likely to have settled on the most practical balance between quality and diminishing returns.
I bought a good grinder about 6 months ago - a Fellow. I changed nothing other than the grinder and my coffee improved. And it is so much more enjoyable to use: Less mess and static, less noise, and everything feels nice to use.
There's something about the sound, the smell, and the feeling once the last bean is ground, that just works for me.
Maybe some years ago I'd have chastised my future self for enjoying something I certainly couldn't identify in a blind test, but nowadays I'm all for "whatever works."
I am using a Breville precision brewer, but would love to upgrade to a Moccamaster one day.
Have you noticed any kind of issues in term of build quality of their products?
Edit: Actually, the comments are still visible (for now), but the photos that had been visible (15 or so?) have been memory-holed.
I know a coffee grower who put his beans through a spectrometer to determine whether sun drying his beans actually altered the flavour profile compared to machine drying. He wanted to eliminate placebo mostly I think. He could demonstrate a clear difference in the spectrometer between sun dried and machine dried beans, with both batches of beans coming from the same field, the same year.
I just love how nerdy coffee nerds are!
Higher speed cracks the brittle beans differently, smashing them into a higher proportion of fines.
Fine and coarse particles yield very different proportions of compounds into the water – the less soluble stuff kind of only washes off the surface of the ground particles. Finer particles, more surface, more of the hard-to-extract less soluble stuff.
1) Sourcing high quality coffee to the roast level you enjoy. Try a lot of different coffees - from "Ultra Light" to "American Light" to "Medium" to "Dark" - and find what you enjoy, then find a roaster that produces those coffees to a high quality standard. There will not be a ton of these roasters in your country. Maybe even just a couple, even if you live in the US.
2) A good grinder, of course. Fortunately in the last few years this is wayyyy more accessible. There are pretty good options starting around $300, and the workflow isn't terrible for these picks, either. Of course the sky is the limit here, but it's really vital to a good cup.
3) Good water. You'll want to either find a bottled water brand you like for brewing, or use an reverse osmosis (can be a gravity type) system and remineralize it. Cafes do this (if they are any good) and you should too. There's a chance your tap is great for coffee, but only if you're pretty lucky.
4) Decent brewing equipment. The cheapest is a v60 for pour over. You can make good coffee with pretty much any machine, but some will get in your way and cause you to have to fuss with them much more.
Then, after those, is technique - and the most important part of technique is really grind size and water temperature (I suggest you do not go above 88c in most cases).
I've worked and RV'ed throughout the USA and Canada. Canadian urban areas tend to have good quality tap water for coffee making. Canadians know that in only a few seconds the water will run truly cold. The USA's tap water as one gets further south from the Canadian border has generally dreadful taste and temperature, meaning chilled, bottled water is a necessity.
These are all pretty lightly roasted coffee though. That may not be to your taste.
I recently switched my ancient ~£50 grinder for a ~£250 grinder and the change in the quality of the espressos is very noticeable.
The importance of technique was demonstrated to me over half a century ago. I grew up in Santa Cruz which has the Santa Cruz Coffee Roasting Company. They have been doing the pour overs since the early 80's. They have two cafes. A sit down large cafe and about four blocks away an annex in the bus depot (no longer there). The annex was basically a small room with a coffee bar. Both the main cafe and the annex did the pour over with the same coffee, same bad city water (probably filtered), same kind of grinder and same coffee bar pour over setup. The only difference was the cafe was large and the employee pouring would walk off and do other job related tasks. In the annex the person pouring was trapped and therefore much more attentive to the pour. The annex had consistently vastly better coffee.
As to "Maybe even just a couple, even if you live in the US.". I now live in Portland with 48 independent roasters. They all suck? I wonder how they would rate your coffee roasting. Yes, slathered on a bit thick.
I love coffee because the good stuff is really good. The decent stuff is still pretty good and the bad stuff is passable when you really need it.
For all you know, both locations could have had totally different water compositions, anyway.
> I now live in Portland with 48 independent roasters. They all suck?
No. I didn't say that.
Who is your favorite roaster/what's a recent favorite single origin you have purchased?
This seems to go against conventional wisdom, which says that less coffee will reduce brewing time and a coarser grind will also reduce brewing time, and consensus seems to be that you want a brewing time somewhere between 20 and 30 seconds. Or did I misunderstand something?
Anyway, the reasoning seems sound, so I'm going to have to give this a try.
"most reproducible" -> Does not mean good.
A lot of generic weak coffee is 'consistent', but not 'good'.
> Pabst echoes that advice: “My recommendation for people at home, without knowing anything they are doing, 90% chance that if you use less coffee and grind a little coarser [your coffee] will actually taste better.”
So it's not just about consistency, but also quality.
This is why I think the Aiden is underrated. It way more consistent than I was when doing pour over but still lets me tweak variables.
A pet peeve of mine is when people mention "weak" coffee. What does this mean?
I did see a video on americano's recently where steaming the water to heat it rather than using a kettle or water from the espresso machine's boiler made a better drink. That does intrigue me and I'll probably give it a try this weekend.
Lately I've been making mostly decaf and it's really hard to get a good shot no matter what I try. Drip coffee comes out great, but my decaf espresso always seems to have a real harshness. Beans are fresh and my water is good, so I'm thinking it's time to replace the burrs in my grinder.
Was it Mr Hoffmann[0]? He has a decent explanation for why this might be the case too (and does an experiment later which points to it maybe being dissolved gases.)
> Espresso is a 25–35ml (.85–1.2 ounce [×2 for double]) beverage prepared from 7–9 grams (14–18 grams for a double) of coffee through which clean water of 195°–205°F (90.5°–96.1°C) has been forced at 9–10 atmospheres of pressure, and where the grind of the coffee is such that the brew time is 20–30 seconds. While brewing, the flow of espresso will appear to have the viscosity of warm honey and the resulting beverage will exhibit a thick, dark golden crema.
I have no problem with calling soup espresso. It's ground coffee brewed under pressure in an espresso machine and that's good enough for me.
[1]:https://sca.coffee/sca-news/25-magazine/issue-3/defining-eve...
But I also do enjoy ~6bar shots using a traditional lever style machine.
But, I think for any recipe, "total brew time" is just a way to communicate contact time with water, and should NOT be a goal unless you're trying to copy what someone else did with that same coffee, and is IMO more important for pour over in that regard than espresso.
https://www.cell.com/matter/fulltext/S2590-2385(19)30410-2
They suggest a courser size and less pressure to avoid channeling.
I’ve been using this technique for a while, I think the results are better (but of course there’s a strong bias when people think they are doing the cleverer thing in food preparation).
For light roasts I hold the pressure at around 1 bar for ~30 seconds before increasing to 7 or so.
I can make bad coffee every time myself by putting 2 spoons of vinegar in it.
Also
> This can be achieved using an espresso machine (figure 1), or with smaller contraptions at much lower pressures such as a moka pot or AeroPress.
Please, just stop. They're not even remotely close.
tone is in the hands.
and if you dont know or instantly understand what various foods sound like when things are going right, stay out of the kitchen.
my life has been blessed by some world class mentors, and when I watch a true master, say, barista at work, operating with a focus and good cheer, idistinguishable from a ferocious beast in there lair, then yes, I stand down, simplicate MY process and have another go, which has in fact resulted in my ability to make a consistent brew that I am very happy with.
take your pedals, and other gadjets down to the curb, and work with an absolute minimum till it starts to click.
As for the 6 bar course grind theory: You may maximize the extraction of soluble coffee mass, but the concentration will be lower. It does not take very much extra water to ruin the taste and texture of a latte.
I do not, nor have I ever, utilized the services of a barista. I make coffee at home or I purchase it from Wawa, Sheetz, 7-Eleven, whatnot.