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Comment by mr_mitm | Hacker News Reader

> The bottom line of the team’s experiments and mathematical modelling is that to get the most reproducible shots just use less coffee and grind it more coarsely.

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.

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These was actually a sort of fun and popular research paper about this,

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.

Ah, too bad my machine doesn't let me set the pressure

You're spot on, but this coarser, faster-style shot is called the "turbo shot" and you don't actually have to use less coffee, you can actually use more - just compensate your grind to brew quickly. You will get more consistent results here, but they're very different from traditional espresso.

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.

Reproducibility doesn't mean good.

I can make bad coffee every time myself by putting 2 spoons of vinegar in it.

They failed to mention the important point, that you have to be able to reduce the pressure to increase the grind size. I am convinced the best espresso you can make is at 6 bar, since you can grind the coarsest possible. It comes out sweeter and richer at the same time.

Some people go all the way down to 1 or 2 bars (soup espresso). I've mostly seen it in the context of very light roasts and I tend to buy darker roasts so I really haven't spent much time investigating it.

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.

> steaming the water to heat it rather than using a kettle or water from the espresso machine's boiler made a better drink

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.)

[0] https://www.youtube.com/watch?v=0HdzJz_evNw

Yes, that's the video. He doesn't seem to be a fan of americanos. It's one of my favorites so I'm pretty interested in new ideas for one of the most basic drinks.

1-2 bars isn't really espresso, it's a moka - which can be quite good in its own right. It falls into the genus of pressurized brewing though, so same genus different species. There's a no man's land from 3-5 bars that is not really used and might be worth exploring, but most 'standards' consider 6 bar the minimum to be a true espresso.

The SCAA (Specialty Coffee Association of America) has an even more restrictive definition[1]:

> 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...

Of all the standards, I find the SCAA the least useful. That was the standard 30 years ago, but nobody serious about improving their craft is brewing such a watered down espresso anymore, and a 1:2 ratio is the most common one. So 15g for 30ml. And for pressure, modern consensus is that 9 bar is the high upper limit. 10 almost always leads to a harsh cup. I find the 6 bar lower limit to be a tipping point in the concentration, such that lower pressures are more similar to drip than to espresso - the viscosity and mouthfeel changes dramatically. So I can't agree that whatever comes out of an espresso machine should be called espresso. But we are debating vernacular here, I just hope you enjoy your cup of coffee!

Well, pressure builds when the coffee bed restricts the flow of water. So if you don't have much restriction (really coarse grind) you're not going to build pressure :) so you don't have to actually change any settings to get a reduced pressure at the puck.

But I also do enjoy ~6bar shots using a traditional lever style machine.

Yes of course, but by dropping opv pressure on most home machines that also drops flow due to opv bleed off. If you have your opv at 9-10 bar you get a full flow shot on a coarser grind - which is way too fast. You need to drop pressure until you can keep your wet time the same (I use the pretty standard 17g coffee 34 ml out, 34 seconds wet, upped to 40 seconds because I use preinfusion). If you have a fancier machine you can just adjust flow directly, but then you can set pressure directly so why wouldn't you do that too.

Yeah.

"most reproducible" -> Does not mean good.

A lot of generic weak coffee is 'consistent', but not 'good'.

Sorry, maybe I should have quoted the next line as well:

> 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.

"taste better" does not mean quality either. What do I know about their tastes, they're scientists not baristas (in the article baristas were only asked about process options). Also they didn't discover anything new, just confirmed what everybody was telling them. And not at least, there are different methods of making coffee, while they smeared their espresso machine results interpretation over everything - like for instance to make Turkish coffee (aka pot) you must grind it the finest and use more.

Reproducible is necessary but not sufficient for consistently good coffee. If you can’t reproducible what you did, you aren’t able to make changes to improve over time.

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.

Good is totally up to the person's tastes, anyway. Turbo style shots are the end-all-be-all for a lot of people who enjoy espresso. For other people, they hate it, for a multitude of reasons.

A pet peeve of mine is when people mention "weak" coffee. What does this mean?

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