Three Questions with Wobble Disk Roaster Maker Larry Cotton

"The wobble disk stayed in the picture forever. That was the one thing that I really discovered, and that worked very well to keep the beans equally browned. It did a really good job of circulating the beans. The beans have to move, and they really do move well with the wobble disk."

"With no drum and no fluid air bed, the home-focused design keeps beans in constant motion on a nutating metal plate at the base of a cylindrical chamber, heated from below. Users can control temperature by situating the heat source closer or farther away, while the disk's wobble speed is adjustable and chaff exits freely through the open top."

"The chamber can be built from an 8-cup flour sifter, and the wobble disk could be cut from a 13-inch pizza pan. Builders of these devices often pair a low-cost motor with a heat-gun base, then add basic fasteners, wiring and a simple frame. Proponents say a wobble roaster capable of roughly a 350-gram batch can be built for about $100 to $150, all in."

The wobble disk coffee roaster represents an innovative DIY approach to home coffee roasting that operates without a drum or fluid air bed. Instead, beans move continuously on a nutating metal plate within a cylindrical chamber heated from below. Temperature control is achieved by adjusting heat source distance, while wobble speed remains adjustable and chaff exits through the top. The design's simplicity enables construction from basic materials like a flour sifter and pizza pan, paired with a motor and heat gun, costing approximately $100-$150 for a 350-gram batch capacity. This technology has gained momentum organically through DIY forums, videos, and shared schematics rather than commercial marketing, with Larry Cotton, a retired power-tool designer, credited as a key innovator who refined the wobble disk mechanism after years of experimentation.

Read at Daily Coffee News by Roast Magazine