On the contrary Ben I think you have brought up a very good point, and I think your roaster was pulling your leg...or else he is suffering delusions of grandeur...no one, but NO ONE, who really knows anything about coffee, is going to stick to a recipe for brewing coffee least of all subscribe to the infamous "timed extraction" baloney. Your roaster cant possibly "...roast, and blend theie coffee to get a certain taste profile *****at a certain extraction??*****..." unless the letters after his name stand for Merlin the Magician. Most roasters I know who know what they're doing, when brewing espresso, dont time anything, they just watch the pour & adjust accordingly to what the pour looks like and tastes like. If they dont like what they taste they make an adjustment, watch, brew & taste again. So much depends on a number of variables not the least of which is the size of the humble coffee filter being used, not to mention how the characteristics of the coffee change over time, and the difference in delivery of brewing water from machine to machine.