What is a WDT tool and do I need one?

A WDT (Weiss Distribution Technique) tool is a thin needle or set of needles used to stir and distribute coffee grounds in the portafilter basket before tamping. It breaks up clumps (common in fine espresso grind) and creates a uniform density across the puck. For many grinders, WDT makes a noticeable improvement in shot consistency. You can buy dedicated WDT tools for $10–$30 or improvise with dissecting needles. It's a low-cost upgrade with meaningful impact.