gscace wrote:WRT taste - I've been mostly investigating a lot of the physical effects of variable pressure on the extraction, and learning about how to do it. I've been doing this because varying pressure doesn't make the coffee suck. It tastes good enough to warrant spending the time learning about the system, and I am enjoying the taste and the learning process. Yesterday I pulled a couple of shots for a third party both with the profile described above, and without any profile at all. There was a difference in taste. Next weekend I hope to do some blind testing in which I brew shots for folks with both profiled and non-profiled pressure, seeking to learn if the difference can be reliably detected and which shots are preferred.
I hate to keep repeating myself; but I truly believe black box methods, which go directly from the perculation's environmental variables like temperature or pressure to taste, are a dead end.
If the the coffee in the cup isn't different, how can the taste be? If the taste is
different, is it because the pressure profile profile had 6.5 bar for 13 seconds, or because there's different stuff in the cup. The answer is obvious -- science is about connecting the toe bone to the foot bone, etc. etc., not just about correlating the head bone's nods to the toe bone's taps.
The simplest set of measures are to weigh the puck before and after brewing, and to weigh the shot. This tells you how much of the puck has ended up in the cup and how much it is diluted with water. If my research on this is correct, the taste roughly follows the taste wheel -- the acid and bright bitter compounds extract first, the caramels and roast flavors later. With a straight pressure pump that I used in my experiments, most of the extraction was done by 20 seconds, and it ran at 15 to 18% for high doses, 20 to 24% for low doses in the same basket. The end of the shot, beyond 20 seconds, was mostly just water.
It sounds that pressure profiling can change this course of events and create more flexible controls. Once you know what is getting into the cup at what time, you'll know what to taste for, and how to tune your profiles.
You should put off your blind testing until you've "white-boxed" pressure profiles at least this far.
A huge hats off for coming up with a commercially viable system of doing this -- but now the job is found out how it affects the shot, and only secondarily how it affects the taste.