I'm uploading a slightly revised version of this -- more v. less aggressive along the horizontal axis rather than using different terms (aggressive v bland).
emradguy wrote:I'm not sure I understand your chart...or maybe you have things backwards? Under-extraction yields a sour shot while over-extraction yields a bitter shot. There are many factors than can affect the degree of extraction of a shot.
That is exactly my question in posting this. Do I have it backwards or sideways or...? The way my mind works is that particle size (grind) and number (dose) are the easiest variables to manipulate in a consistent way. My conceptual framework is:
DOWN: an under-extracted shot tastes sour so make the particles smaller (finer grind) or put in more of them (larger dose) to reduce the sourness; pushing the same amount of water through this puck will result in a slower flow (longer shot time to achieve the same 50% brew ratio);
UP: an over-extracted shot tastes bitter so make the particles larger (coarse grind) or put in fewer of them (small dose) to reduce bitterness; pushing the same amount of water through this puck will result in a faster flow (quicker shot time to get a 50% brew ratio).
I actually have no idea if the horizontal axis is true. Most of my taste problems are related to bitter/sour. I've also tried using Al's rule but it didn't work for me because it added shot volume to the mix -- too many variables and the solution became unidentifiable (others might be able to bootstrap or maximum-likelihood their way out of that problem).