2+2=3.14159265
A ratio of 1:1 has in theory, the same value as 4:4, and 8:8, etc. When discussing brewing ratios as it relates to flavor profiles in espresso, this isn’t necessarily the case. It can be helpful to consider the weight in grams of the ground coffee being used, and the weight of resulting liquid. You can take 20 grams of espresso and extract 20 grams of liquid in 30 seconds. You can then take 40 grams of espresso and extract 40 grams of liquid in 30 seconds (or 30:30, 10:10, etc). In order to maintain consistent brew time you would of course have to compensate for variations by adjusting the grind size. Both procedures would result in identical brew ratios of 1:1, or 100%, but the flavor profiles would be very different. Differences would be caused in part by the effect of identical water temperatures on a different mass in the portafilter, as well as different reactions from the pump exerting the same amount of force on the different mass. Different flavor profiles would also be caused by extracting different percentages of dissolved solids, a factor that is probably also directly related to the particle size of the coffee (among other things).
What does this mean? I’m not sure except that it’s data that could be useful when tracking variations. Since I typically pull shots that result in less liquid (by weight) than the ground coffee I’ve used (usually in the neighborhood of 20:16), I typically pull ristretto shots. Sometimes though the shots taste better in the neighborhood of 23:16, or with even larger differentials. Sometimes with smaller differentials. But that’s all I’ve really discovered. That, and it can be helpful to talk to Andy late at night sometimes.
