I've been making a lot of aeropress brew lately, and today it suddenly dawned on me that I really don't know why I bother to bloom with a partial amount of water.

I understand that with fresh coffee on a pourover grind, too much water at first will puff the coffee up too much and cause overflow and/or channeling down around the outer edge of the coffee, resulting in early drawdown/underextraction, if not also a mess. So the bloom with a small amount of water is essential to the process of developing a proper brew, prior to adding the full amount of water.

With french press (total immersion brew), the full amount of water is added with a light stir; the saturated coarse-ground coffee blooms into a crust, and after 30 seconds or so, we stir that bloom down and then put the plunger over the top, let it steep, then maybe one last stir a few minutes later, then plunge. The aeropress is an immersion brew method, not a pourover, so why am I bothering to bloom it like a pourover?

I looked up some recent championship recipes, and most, but not all, involve a small-water bloom. Heart Coffee Roasters suggests a full pour right off the bat. Stumptown starts with a partial pour. Blue Bottle: partial pour. Wendelboe: Full pour.

I started off as a full pourer, in my early aero days. Then at some point I started partialling, probably due to influence of what I'd seen and read, but strangely I don't remember it being a conscious decision, I just started doing it that way. For my afternoon coffee I went back to full pouring. It's easier, and the result tasted and felt just as good to me, if not better.

I agree with you - there seems to be no extraction-related reason to start with a partial pour bloom. If you are maxing out the capacity of the aero, the partial pour may help keep it from foaming over the edge, but otherwise full pour should be fine.

If you can manage to keep the grinds from stratifying by using a bloom and gentle pour, you may end up with a better cup. I think this is the aim of the inverted method. All bottom filtered immersion brewers are flawed in this respect.

Post by endlesscycles » March 8th, 2015, 8:07 pm

If you can manage to keep the grinds from stratifying

Marshall, please explain. I am not familiar with the term 'stratifying' with respect to coffee grounds. I did an H-B search and couldn't find the term.

Try without a bloom and with one. I find it tastes better with a bloom after watching them brew this way at Heart Coffee Roasters in Portland. Ironically their website instructions don't include a bloom.

I was under the impression that it had to do with wetting the grounds evenly. When it blooms some fraction of grounds gets pushed up by the foam and probably doesn't extract very well like that, especially with a shorter brew time. I tried doing a partial bloom for a while but was annoyed by the extra step that didn't seem to improve the coffee noticeably. And it also placed a limit on the temperature profile. So I pour fully and then push the grounds down under water gently with a spoon. To be honest I'm not sure how it much it matters.

Magic recipe, magic recipe.

endlesscycles wrote: All bottom filtered immersion brewers are flawed in this respect.

Interesting thought. In what way are they flawed regarding stratification? I can see that the filter in a Clever could trap high concentration brew under the filter if coffee added first, or low concentration if water added first, but this would have less of an effect with Bonavita (no significant volume under filter) & Aeropress inverted

Surely the stratification in these brews (excepting the Clever) is far less than the fairly massive swing in %TDS of varying portions of a drip brew as it exits the cone?

I mean there is a stratification of the grounds themselves. With a low turbulence percolation brew, the boulders hold back the fines. In Aeropress and Clever, the boulders float to the top while the fines sink to the bottom.

You can also address this migration of particle sizes with a stir after the first fill of the Aeropress and a stir about 30 seconds before pressing through. This technique applies to a non-inverted method. FWIW Alan Adler told me he doesn't conceive of Aeropress brewing as a long steep and only brews for about 30 seconds after a 10 second stir before pressing through. This requires a finer grind. When he presses through he puts both hands on the plunger and leans into it without much force.

endlesscycles wrote: In Aeropress and Clever, the boulders float to the top while the fines sink to the bottom.

Doesn't this work just as much in our favour? The fines sinking quickly & settling together hopefully in such concentration as to stall their extraction, the boulders still floating/in low concentration liquor, thus able to carry on extracting until knocked down, or sinking of their own accord later in the brew?