Zero-retention commercial grinders prioritize clean single dosing, precise burr alignment, and minimal purge waste-ideal for cafés testing coffees or serving high-end espresso menus.

Flat burrs often sharpen acidity and flavor separation, while conical burrs add body and sweetness, trading some clarity for a rounder cup.

Fix channeling by grinding finer, distributing grounds evenly, and tamping level. Spurts from a bottomless portafilter signal puck cracks, uneven dose, or poor prep.

Troubleshoot pressure profiling by checking pump output, flow restrictions, valve response, and puck prep in sequence to isolate espresso machine pressure faults.

Stable water starts with measured alkalinity, hardness, and TDS. Filter, remineralize, and test routinely to keep extraction balanced, repeatable, and expressive.