WDT is short for the Weiss Distribution Technique. It's a term that might put some people off as it sounds complex. We will also dive into. What is the WDT (Weiss Distribution Technique)? The Weiss Distribution Technique, commonly known as WDT, is a method of preparing coffee grounds for espresso extraction by evenly distributing them in the portafilter basket before tamping. If you haven't plucked up the courage to ask the barista what this tool does for fear of being frowned upon. The technique involves using thin needles to stir ground coffee inside the portafilter before tamping, breaking up clumps and distributing grounds evenly. It breaks up clumps and eliminates channels, resulting in more balanced extraction and significantly improved espresso flavor profiles.