ladalet wrote:Perhaps I may be making this more complicated than it needs to be. I guess I could have just asked that each user simply report how much espresso volume he or she is able to "consistently" extract from his or her machine before bloinding. I was looking to correlate basket volume in dry coffee to a predicted "typical" liquid volume of extracted espresso. In any event I am sure that any new lever user would find it helpful to know a reasonable range of extracted fluid they should be able to "consistently" achieve out of their machine before blonding. It is just I variable that can be removed from the equation if you know that, for example, after pulling 1.5 oz of espresso that likelihood of blonding should be expected increase as one pulls more volume, and that one should (probably) not blame technique at this point. This could save time and frustration.
timo888 wrote:
But you are making it less complicated than it is* yet in oversimplifying things you are not really simplifying things for the newbie barista. To make things simpler for the newbie barista one need only say:
it depends upon the dose
so vary your dose by a couple of grams either way and see what happens
it depends upon the grind
so grind coarse and grind fine and grind in between and see what happens
it depends upon the roast
so buy some light roasts and some dark roasts and some darker light roasts and see what happens
it depends upon the tamp
so tamp very lightly and tamp very hard and see what happens
After that little litany one inscribes the tetragrammaton of the espresso god: YMMV
Regards
Timo
*The porosity of the coffee and the water draw are the two primary factors that determine the volume of beverage in the cup. But the porosity is itself determined by quite a few interrelated factors which can produce dozens of variations.
the dose (basket maximum is not a valid measure -- baristas do not always dose to the max)
the processing of the bean
the blend
the roast depth
the age of the roast
the humidity
the grind
the force of the tamp
the water temperature
the pressure
the height-to-width ratio of the cake
SantaCruzan wrote:The AndyS chart referenced at the top of the thread is what helped me finally abandon a multi-pull technique. With a 49mm Pavoni basket, I find ± 12 grams to be about the right amount of dry coffee. This amount of coffee paired with a single pull in the Pavoni, typically delivers, to my taste, a pretty darn good shot (usually 1-1/3 oz but with a lot of variance). Initially, I spent far too much time trying to extract that magical "2-oz in 28 seconds" shot - a semi-auto mantra that just doesn't translate to lever machines.
ladalet wrote: the variables you list are ... important and can affect shot volume. However they are more or less equally important (covary) to all machines independent of basket size. Basket size affects maximum dose size and makes machines unequal in expected shot volume with all of your listed variables being equal or optimized. Basket size places a limit to available shot volume.
ladalet wrote: Independent of the variables you have listed, a machine with a 49mm basket that holds a 11 gram dose will not extract the same volume of espresso as a machine with a 58mm portafilter that holds 18 grams.
ladalet wrote: And, if our understanding and expectation is that a double is 2oz of extracted espresso and the most that ones machine can produce is 1.5 oz of extracted espresso that one may reach the false conclusion that there is a problem such as channeling when attempting to extract that last .5 oz. There is not enough coffee in the basket to get that last .5 oz without blonding. There may be exceptions where the conditions may allow a 2oz extraction, but not consistently.
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