The Weiss Distribution Technique (WDT) is a distribution method for espresso making. Using a fine needle or similar tool, the barista stirs the coffee while it sits in the portafilter. A funnel placed above the portafilter helps prevent spills. The stirring action breaks up any clumps, and evens out the density of coffee within the puck. The result is reduced channeling, and higher, more even extractions.