matt1203 wrote:what make a dry puck ?
If the puck doesn't make contact with the dispersion screen when the coffee expands, the puck's surface will be wet with a sandy/lunar-esque texture. As long as the puck is consistent, wet or not, it's fine. For reference, see prior discussions 1
... or just puckology
in general. If you want a dry puck, dose a few grams more and/or wait longer before removing the portafilter.
matt1203 wrote:does that means a good shot of an espresso?
allon wrote:There are a couple of things that can be diagnosed from a puck...
I've not discovered a correlation between the appearance of the puck post-extraction and the taste of the espresso. Moreover, there's nothing inherently wrong with small puddles of water on the puck's surface, though it should be consistent from shot-to-shot. That is, if you see big puddles one time, dry as sand the next, that's a problem. But if the puck's surface looks and feels basically the same each time, I believe you've exhausted the value of puckology.
That's why I am wary of claims that one can see evidence of channeling on the puck's surface. Afterall, most espresso machines have 3-way valves and they depressurize from 130 PSI to 0 in an instant. I think that any fissures are as likely caused by rapid depressurization as channeling during the extraction.