Equipment & Tools
WDT (Weiss Distribution Technique)
A puck preparation method in which thin needles are stirred through ground coffee in the portafilter basket to break up clumps and distribute grounds evenly. Named after John Weiss, who popularized it online.
En Profundidad
WDT uses acupuncture needles or fine 3D-printed tools inserted into the coffee bed and moved in circular or stirring motions to declump and homogenize particle distribution. Clumps created during grinding are a primary cause of channeling, where water finds a low-resistance path and over-extracts a narrow area while under-extracting the rest. WDT has become standard practice in competitive barista routines and is considered one of the most effective low-cost improvements to espresso quality.