Does 100 cc water use per triple shot sound about right for making a triple shot, including the water needed for preinfusion? I figure 1 shot =~ 30 cc water, but the "brew ratio" value reduces the water consumption somewhat, and the volume of the portafilter basket increases the water somewhat.
Thanks in Advance
Joe

I am confused. Where is all of that extra water going? Are you including water to do a flush?

Well, an oz of water is about 30 grams. A shot is about an ounce of beverage. A triple shot would then be about 3*30 grams of water, or about 90 grams of water. A gram of water is a ml of water, so if all the beverage was water then a triple would use 90 ml of water. The puck is wet (sometimes downright soggy!) so some water is "overhead".

Reason I am trying to estimate this is for the design of a piston pump; I'd like to be able to push a triple shot with a single stroke of the piston. It seems like a piston capacity of 100 ml might be about right, but this whole "extraction ratio" business is tricky (at least to me). I know that the water carries good stuff with it when it passes through the grounds; this will use up some of the 90 ml of a triple.

Thanks for asking!

Do you mean a triple ristretto (e.g., 21 grams coffee in, 21 grams beverage out for brew ratio of 100%) or a triple espresso (e.g., 21 grams coffee in, 42 grams beverage out for brew ratio of 50%)? Most baristas who use triple baskets are making ristrettos, so the drink's water volume will be closer to that of a double.

Out of curiosity, I just made a double "normale" espresso (18 grams coffee in, 36 grams beverage out). To measure the total water used, I weighed a cup of water and put the machine's water inlet tube into the cup. It was ~80 grams lighter after the extraction ended, though some of the water was lost to the driptray when the grouphead depressurized. That's consistent with the estimates I've read of ~90 grams of water used per double for a pump-driven commercial espresso machine.

That said, assuming we're talking about a piston type lever espresso machine, the puck will be at least be partially infused with water before the chamber is pressurized, so the volume of the piston doesn't need to account for the total water usage, only the portion that must be pressurized. Assuming the puck is allowed to absorb at least half of its total prior to pressurization, you won't need nearly 100 grams of pressurized water. Then again, if this is a lever type piston, there's potentially an air pocket under the piston that may prevent the chamber from filling 100% prior to pressurization...

Thanks Dan, I did a similar experiment and came up w 100 cc estimate. A 21 gram basket is about as big as they come. I feed my machine from a jug so the next step is to make a weeks worth of coffee and measure the numerator and denominator.