Roasting Coffee Beans with Your Own Homebrew Machine

If you like coffee, you might get something like a Keurig to make it for you automatically, or perhaps even a French press to give you more control over the operation. If you want to take this control another step further, why not roast your own beans? While rewarding, the process is a bit more involved, as shown by Alex Campbell’s DIY one-pound fluid bed roaster.

Campbell’s build uses a roasting element to heat up the beans, and during the process, a hot tub-style blower sucks chaff out. This also agitates the beans, visible thanks the clear roasting chamber. The waste is then sent to a dust separator — similar to one that’s normally used in woodworking — which is then deposited into a small jar below.

The system is controlled with an Arduino, along with a computer linked up via serial to run the roasting program. This actuates a solid-state relay (SSR) to activate the heating element using zero-cross detection circuitry, and there’s a triac to control the fan. A thermocouple provides some indication of the system’s temperature, allowing it to run in automatic or manual mode depending on what is needed.

You can see a technical overview of the roaster in the first video below, and video of it in action via the second clip.