Who doesn't love a good espresso? But as I'm sure every great barista knows, the real key is all about permeability...As every great barista also knows, the ideal espresso shot (double, of course) is 60 ml, extracted at a brewing temperature of 94 degree C and a pressure of 9 bars, and takes 26 seconds to "pull". The standard diameter of the brewhead (and therefore of the coffee "puck" through which the water flows) is 58 mm. The "puck" is typically 7/8" thick. (A) What are the hydraulic conductivity and permeability of the ideal espresso puck? Be mindful that fluid properties (density and viscosity) are dependent on temperature, so you'll need to do some digging for the right values. (B) In the case of the overzealous home barista, a common mistake is to grind the coffee too coarse or too fine. Suppose all of the above parameters are the same, except that the result is a measly 25 ml espresso shot that takes 57 seconds to produce. What's the permeability of that puck 13 pts, and what should be changed to fix the problem?