How-To: Roast Coffee with a Popcorn Popper


By Mark Frauenfelder
Relaxing in a coffee house with a professionally made cup of espresso or cappuccino is one of life’s simple pleasures, but I also enjoy making my own coffee drinks at home. I buy whole beans online and grind them in a coffee grinder. I’m a pretty good home barista, if I do so say myself.
The one coffee-making activity I’ve always avoided, though, was roasting coffee. I assumed that coffee roasting required large, expensive machinery and considerable training. But a few weeks ago, I heard about a way to roast coffee using a hot air popcorn popper. I gave it a try and found out it was fun and very easy. It takes less than 15 minutes to roast a small batch.
Home roasting is not only fun, it’s economical. Green beans cost about half as much as roasted beans, and they stay fresh up to a year. (Roasted beans lose flavor in a matter of days.)
Here’s how to roast your first batch.
For a PDF of this tutorial, visit the technique page on Make: Projects.


Green coffee beans, I get mine online from Sweet Maria’s


Hot air popcorn popper, the best has a chamber with a flat bottom and vents around the side, such as the West Bend 82416 Air Crazy popper, $25
Metal colander
Large wooden spoon, optional
Small glass jar with lid
Timer A timer will let you know when to start listening for the sound of the “first crack” and “second crack” described below. I use the stopwatch app on my iPhone.


Step 1: Set up your tools and materials in a well-ventilated, well-lighted area. I roast in the back yard, not only because the roasting process creates a strong smell that would linger indoors, but also because the beans shed a lot of chaff that floats around and settles everywhere.
Step 2: Put 1/2 cup of green coffee beans into the popper and turn it on. If the beans spin quickly in the chamber, add more beans, a bit at a time, until the beans spin very slowly. Don’t add too many beans or you will end up with an uneven roast.
As the beans begin to roast, keep your eyes and ears open for three telltale signals:
A. The first thing you’ll notice is the production of chaff, which is lightweight, amber-colored fluff that floats out of the popper.
B. The beans will start turning faster as the water in them evaporates.
C. Sometime between the 2- and 3-minute mark you should hear the “first crack.” It sounds like a dry twig snapping.
All three things are signs that the process is moving in the right direction.
Step 3: If you like very light roast, you can stop anytime after the first crack. Most people like a darker roast, though. (The lighter the roast, the more you can taste the coffee; the darker the roast, the more you can taste the roastiness.) Keep listening for the “second crack,” which is quieter than the first crack. I like to keep roasting for a couple of minutes beyond the second crack, which gives me a dark roast. If you go much longer, your coffee starts to get into “Charbucks” territory.
Step 4: Pour the beans into the colander, taking care not to burn your hands on the popcorn popper, which is pretty hot. Stir the beans with a spoon or simply hold the colander and swirl the beans around. This releases the heat from the beans, quickly halting the internal roasting that’s going on. Let the beans cool down to room temperature.
Step 5: Transfer the roasted beans into a glass jar. The smaller the jar the better, because you don’t want a lot of air mixing with the beans (it oxidizes them and kills the flavor). Don’t screw the lid on too tightly, because the beans should be able to “outgas” overnight. After that, you can screw down the lid. The next day, open the lid, put your nose over the jar, and inhale deeply. The aroma is incredible. Now, prepare your coffee as usual and enjoy your first home-roasted cup!
About the Author:

Mark Frauenfelder is editor-in-chief of MAKE.

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