alt Hacker NewsAfter the last one of these posts talking about cold brew coffee I attempted to replicate the results by just throwing some water and coffee into an ultrasonic jewelry cleaner. Results were not satisfactory. I wonder if extracting the transducer from the jewelry cleaner and attaching it to my Portafilter would work.
It'd be a learning experience to find the right settings.
Coffee usually goes in two directions. Under-extracted (sour) or over-extracted (bitter). Things that will affect the extraction are temperature (hotter usually means more extraction), time (longer = more), grind size (more surface area in smaller grinds = more), pressure (higher = more) etc. Roast levels also matter.