Coffee roasting; how complicated could that be? Just heat some beans until they turn brown, and you’re good to go. I recently found some local green coffee suppliers and realized I can buy small quantities for a fairly reasonable price. So I decided I would build my own coffee roasting setup. This is my journal.
While it was appealing to build my own roaster, if a company had a low-priced, good looking unit I figured it might not be worth going through all the effort designing something…
There are many home roasting options, but in general I thought they were either expensive and not good quality, or extremely expensive and of very good quality. Common recommendations are the FreshRoast series, the Behmor 1600, or a Hottop; I’ve listed them below with a few comments:
Essentially what I found was that no commercially available roaster fit my needs and budget. Apparently there is a significant number of people who feel the same way. So many, that there is a subReddit almost exclusively for us.
The r/roasting page is full of people who, like me, want to roast beans at home but not spend too much money. The most common solutions are “popcorn air popper” (so smart!) and to a lesser extent, bread machine + heat gun (uh-oh…)
The air popper solution is kind of perfect; the device gets to the proper temperature, and the fan agitates the beans, just like a fluid bed roaster. The major problem that people run into though, is controlling the temperature or batch size. As far as control, most air poppers don’t even have a temperature reading let alone temperature control. People on Reddit seem, for the most part, to be satisfied with letting the popper reach whatever temperature it reaches, and listening for the cracks.
I like the idea of the air popper, but the idea of having such little control over the process sounds terrible. Lucky for me, Mark Sanders already put together directions for adding a thermocouple and temperature control to any existing popcorn popper. Using a Raspberry Pi microcomputer and a few external components, he built a device that, based on the temperature reading from the thermocouple, will turn the heater on or off. He also wrote a program (in Python) that lets you record the temperature as a function of time save your roast profiles, and repeat profiles you liked. Effectively, this will turn your popcorn air popper into a FreshRoast SR500. Sign me up!
This got me so excited that I went ahead and ordered all the parts I was going to need including green beans, and picked over Value Village for a popper. From what I read, most popcorn poppers will work, though in some cases a popper may have trouble reaching a high enough temperature. Typically the older poppers will work better. I ended up finding a beautifully age-yellowed popper that was conspicuously clean and oil-free for a measly $5.00
This is going to be so much fun…