I believe they are referring to "Weiss Distribution Tool". I have a manual lever espresso machine that I used daily for a decade. The idea behind WDT is real. D

I believe they are referring to "Weiss Distribution Tool". I have a manual lever espresso machine that I used daily for a decade. The idea behind WDT is real. Distributing the grounds evenly makes much more consistent shots. If the grounds are not evenly packed, the water under pressure breaks through a channel and the shot tastes like garbage. It's not quackery, just fluid dynamics. One can argue that grounds can be distributed by other means as well. Stirring with a needle (WDT) is the quickest for me. [1] https://coffeechronicler.com/wdt-tools-technique/ https://coffeechronicler.com/wdt-tools-technique/