Backyard coffee roasting


My supply of decent roasted coffee is at dangerously low levels, so my daughter and I spent a short time roasting coffee today. There are some great books and online resources for coffee roasting, but in a nutshell, here’s my simple method (purists will cringe; you can be much more precise about all of this. I overroasted mine a bit today):
I used a hand-cranked stovetop popcorn popper, a stove (I roast on the side burner of my gas grill to keep the smoke out of the house), a high-temperature thermometer (such as the thermocouple on a multimeter), green coffee beans, and a colander.

  1. Heat the popper to around 400° Fahrenheit.
  2. Pour in the green coffee beans, close the lid.
  3. Slowly crank the handle for around six minutes, listening for “first crack”.
  4. Keep cranking while you wait 2-3 more minutes, then open the lid, blow off some smoke and check the color of the beans. When they approach the roast color (not black!) you desire, kill the heat.
  5. Dump the beans into the colander and start shaking and stirring them to cool and let the chaff fly off. Once cooled, put them in an airtight container, or even better, a container with a one-way valve to allow degassing of CO2.


That’s it. If you’re roasting beans for drip, French Press, or vacuum pot enjoy your newly roasted coffee right away. If you’re making an espresso blend, wait an agonizing two or three days for the CO2 levels to drop, otherwise you’ll have some fairly fizzy crema to contend with.

It makes pretty good economical sense if you exclude the cost of your own labor (this qualifies for a hobby “exemption” in my mind!). I compare $4.80/lb. green beans favorably against $15/lb. roasted beans.

It’s also an eminently hackable pursuit. Popular non-commercial methods include converted air-poppers, the heatgun/dogbowl combo, and grill rotisseries.


John Edgar Park likes to make things and tell people about it. He builds project for Adafruit Industries. You can find him at and twitter/IG @johnedgarpark

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