I agree, it's absolutely not espresso. They recommend watering down the output of the AeroPress but it's nowhere near strong enough for that, as espresso is.

I thought it was weird when I first heard it referred to as espresso, but the official name is "Aerobie® AeroPress® Coffee & Espresso Maker" and there doesn't seem to be any consensus on what _espresso_ actually is. The only common trait is that pressure is used to force water through ground coffee -- the Aeropress does qualify under that definition.

Come on over and visit us at /r/coffee, and we'll set you straight :) There actually is a consensus that "real" espresso has to be brewed with around 9 bar of pressure, and that is the standard used by SCAA ( see http://lrs.ed.uiuc.edu/students/tchen3/espdifine.html ). At this pressure, the consistency and mouth feel of espresso is fundamentally different (it's "syrupy") than that brewed at lower pressure. To achieve this pressure, you need to use an electrical or lever pump. Machines that only get 1-3 bar of pressure like the aeropress or a mocha pot produce something that just tastes more like strong coffee.

Wait, are you saying that the old manual lever-based espresso machines, didn't make espersso? Wikipedia has this to say: "There are two types of lever machines; manual piston and spring piston design. With the manual piston, the operator directly pushes the water through the grounds. In the spring piston design, the operator works to tension a spring, which then delivers the pressure for the espresso (usually 8 to 10 bar; 116 to 145 psi)."

(I'm not disputing the claim that the Aeropress, for all its niceties, doesn't allow for 9 bars of pressure when used as intended)

[ed: That lever contraption is awesome. Searching for appropriate metal filters that could help with generating 130 psi, I fell into the rabbithole of

https://www.tumblr.com/search/aerohacks

and found among other things:

http://www.handpresso.com/

Also, by the makers of the video posted by gp: http://www.spressa.us/ ...]

Absolutely agree on the three important factors. But I'd say the fourth is bean quality. Makes all the difference.

You don't think pressure matters when plunging? I've speculated that a faster plunge might extract more solutes from the coffee grinds due to greater liquid penetration into the coffee grounds from higher pressure.

It's hard to get that much pressure variation with an aeropress. The plunger is around 5 cm x 5 cm, so the full body weight of a male human (say 90 kg) only gives you 3.5 bar. That's if you're standing on your aeropress. A real espresso machine puts out 9 bar.

From practical testing, I'd say it makes a difference, but it's second-order compared to grind size, temperature, steep time.

That's why I qualified it with "a particular roast." But I probably should have added another factor: amount of grounds. I've found the manufacturer's recommendation of two scoops to be ridiculously strong, but maybe that's because I typically use a strong roast and don't water it down.

I'd argue that agitation time, press time and brew technique (inverted vs regular) are also worth considering, albeit not as important as the three you mention (plus bean choice). In particular, I find inverted brew vs regular brew using an Aeropress makes a huge difference.