I always hear how critical the various brewing parameters are, but rarely hear any firm numbers. Being an engineer, these are things I want to know! Well, I came across some recently (link): one quarter to one third ounces of finely ground coffee, one and a half ounces of water, 195 degrees F, delivered at a pressure such that the water is in direct contact with the coffee for approximately twenty five seconds. It’s interesting info, but I’m not convinced, I thought a good draw of espresso was more like 10-12 seconds. I’ll have to continue to investigate this…