What kind of pressure are we taking about? This project would definetely benefit with chating with a barista and understanding the principle of brewing a coffe shot, or working/getting experience with a professional machine. Personally i think the best you can get at home (unless you can afford a pro machine) is aeropress. Dead serious
How do you know this person hasn't had plenty of relevant experience? And no hard disagree on aeropress. You can make great espresso at the correct temperature/pressure with non-pro machines. I make a few a week with a Flair Pro 2 and they're very consistent. Like <$700 for lever+grinder+kettle. I also have an aeropress and it's fine but they make different drinks.
Espresso is typically made with 9 bar of pressure.
An aeropress doesn't actually generate any pressure. It just moves a column of water through a puck of coffee like a percolator. You can buy some special add-ons for the aeropress that cause it to build pressure but it's really just for generating more foamy/crema brew and not getting a proper espresso shot out of it. All that said the aeropress is still awesome and a great way to brew coffee, it's just not going to replicate espresso shots.
About the Aeropress, I guess the question is: When I press it down (in my case, using the elbow for added pressure) how many bars can a typical user reach?
Let's do a little calculation. For an upper bound, let's say you press your full weight onto it and the coffee grounds' resistance is not the limiting factor. That's maybe 90kg, times the acceleration of gravity, for about 900 newtons. That force is applied to a pi*(30mm)^2 or ~3^-3 m^2 area. That gives us a pressure of 900/3e-3 = 3e5 Pa or 3 bars.
James Hoffmann answered this with a modded aeropress with a pressure sensor: a typical aeropress brew is in the range of half a bar. The max he could achieve was 1.5 bars, but like he says, no one brews like that. He also found anything past 0.5 bars began to taste awful.
No. The aim of the aeropress is good extraction , not foam/cream. And i doubt you get 9 bars from that thing in the photo. Therefore i suggest an aeropress (and learn about extraction and taste) instead of building a machine without understanding the principle of brewing a shot. For which you need a ceramic grinder by the way. But do not get me wrong, i am all for open source and building things. It might not be about coffee though.
The builder reuses the pump from a real espresso machine. It might not reach exactly 9 bars, but it's between 7 and 9. I don't know where your skepticism comes from.
Source: I own and repair espresso machines as my hobby and for my daily coffee habit.
Indeed I seem to have misread the answer, and have answered poorly. Thanks for pointing that out. My point is that understanding taste, grinding and extraction will take you a long way. One of the keys for extraction is fixing the variables. If you for example have a steel grinder that does not grind evenly(and burns or heat the coffe with friction) the resulting extraction is a result of hazard. You will have both overextracting and underextracting.In the same way not having consistent ( enough) pressure will give poor results. There are ways to compensate but you are going to have «errors» in the taste. I have trained as a barista, trained with scent kits, and have been given enough home coffe brews (supposely espresso) by coffe fans made with home machines that I lost hope in any of those machines. Really experiencing taste while limiting the method is more benefical in my opinion.
And kust to be extra clear I am not saying that an aeropress gives you an espresso shot.
Pressure is not an issue since a vibratory pump in the most basic espresso machine can produce 15 bar of pressure quite easily. In fact, manufacturers have to put an overpressure valve in their machines to limit maximum pressure to the optimal 9 bar.
Also, this project is about sophisticated temperature and pressure/flow control, something even many/most professional machines simply can't do. So I really don't think the person who built this machine lacks experience in brewing coffee.
>Personally i think the best you can get at home (unless you can afford a pro machine) is aeropress. Dead serious
Given the notoriously grainy mouth feel of aeropress coffee, and the sheer joy I've had out of proper espresso made with even less-expensive home machines (e.g. a Rancillo Silvia, to say nothing of nicer home machines like Rockets), I'm utterly stunned by the weirdness of this assertion.
I wouldn't be more puzzled if you'd said the best you can do at home is a Mr Coffee. Dead serious.
There's a certain sweetness that comes through with a well done shot, along with a real smoothness on the palette without sacrificing body. Certainly all coffee has a bit of bitter going on, but with a properly done shot -- under real pressure, with a dialed in set of variables (grind mass, desired shot mass, shot time, etc) -- it's just part of the party, not the whole thing.
And you can absolutely get this at home, but you need a proper machine. (A Moka pot won't do it. People might LIKE Moka coffee -- lots do! -- but it's not the same thing.) I'd rather pull a shot from my Rocket than go to any shop in town. And, as I said, I've had shots just as good from machines much cheaper than my R58 (like the aforementioned Silvia).
IME, genuinely good espresso is a fairly rare thing. The set of coffeeshops that pull consistently good shots is a much, much smaller subset of [Coffeeshops] than we might expect.
What an aeropress produces is more akin to French press than anything else I've had. It's absolutely nothing like espresso. Since I'm not a French press fan, I end up not caring for it, but that's a preference thing, not an indictment of the method. When it comes to filter coffee (which is to say, non-espresso), I prefer Chemex.
