← All terms
WDT (Weiss Distribution Technique)
Using a thin tool (needle, acupuncture needle) to stir the grounds in the basket before tamping, breaking up clumps and redistributing density.
Category: Extraction — Workflow & Technique
A puck-prep method developed by John Weiss — stirring the grounds in the basket with fine needles (usually 0.3–0.4 mm) after dosing and before tamping. Breaks up clumps and produces a more uniform bed density.
Why it matters — WDT is one of the single biggest puck-prep improvements available, especially for light roasts and modern processing methods. Without WDT, clumps create density variation that leads to channelling.
Good to know
- Stir gently in small circles, just deep enough to reach the bottom of the puck.
- WDT tools are inexpensive and homemade versions work fine — but bent or splayed needles need replacing or your distribution suffers.
Related: WDT Tools