Roast Your Own Coffee: Hot Air Corn Popper

Long ago in a galaxy far far away, it was common to roast your own coffee.

Now, I missed those days by some years, but I have a feeling that it went a lot like a lot of other things. Most people roasted their own coffee in open pans in batches big enough for their own use for a few days at a time. In some neighborhoods, there was a duena who had coffee roasting down to a fine art, and in return for a few cents, would roast up a few extra batches for the neighbors.

For the most part, though, roasting your own coffee was no different than baking your own bread or canning your own vegetables for the winter. It was simply another housewifely skill that disappeared in the wave of modern conveniences that followed WWII. Storebought bread, canned vegetables and pre-packaged, pre-roasted, pre-ground coffee. The era of convenience eclipsing quality reached its pinnacle with instant freeze dried crystals. The pendulum had to start swinging back – and it did, starting in the early 1980s.

The problem was, of course, that home coffee roasting had been out of fashion for so long that no one had been developing any sort of equipment to make it easy for home coffee roasters. That left the field wide open for coffee roasting enthusiasts to fiddle with and adapt other appliances to roasting green coffee beans. The appliance most often pressed into service was the hot air corn popper.

Roasting coffee in a hot air corn popper isn’t difficult. Here are instructions, complete with tips and caveats, for roasting coffee in a hot air popcorn popper.

Choose the right machine

Not every hot air popcorn popper is safe for coffee roasting. Popcorn poppers that introduce air into the popping chamber through a mesh screen in the bottom are not safe. There’s a significant chance of igniting the coffee chaff with those. Instead, use a popcorn popper that introduces are through side vents in the chamber. Several models that are known to work are the West Bend Poppery II, the Hamilton Beach Popaire 2 and the Popcorn Pumper. There may be other models that work as well. The important part is that the air be blown into the chamber through side vents. That directs the chaff up through the chute where you can collect it.

The most popular hot air poppers for home coffee roasting have long been discontinued, but you may have some luck finding them at thrift or second hand stores – or check your mom’s attic.

What Else You Need:

A big bowl, a big spoon(wooden spoon), a thermometer (optional) and two metal colanders or wire mesh strainers

What You Do:

Choose a well-ventilated area to work in. Roasting coffee produces a lot of smoke so you’ll want to be near a ventilator hood or a window to keep from filling your kitchen with smoke. Some people prefer to do their roasting outside for that reason.

Measure out the same amount of coffee beans as you’d use popcorn in your particular machine and pour them into the hopper.

Put the hood and chute back on, including the butter melting dish. Put the large bowl under the chute to catch the chaff that’s blown off the coffee beans as they roast.

Turn the machine on.

Listen for the first “crack”. It sounds like popcorn starting to pop. That’s your cue to start watching your roasting process carefully. It can take about four minutes to reach first crack – and your beans can go from light roast to burnt in 3 minutes or less. Once you hear the first crack, keep close watch on the color and aroma of the beans to tell you when to stop roasting.

When the beans are just a bit lighter than you want your roast, dump them out into one of the metal colanders to start them cooling. You can speed the cooling by stirring them with a wooden spoon, or by pouring the roasted beans from one colander to the other, back and forth a few times till the beans are cool enough to touch.

Store the coffee beans in an airtight glass jar, away from sun and heat. Your coffee will be at its peak at about 12 hours after roasting (though you can grind and use it immediately). It should stay fresh for about five days.

Be sure to clean your hot air corn popper well after using it, following manufacturer instructions.

A quick, down and dirty timing guide for darker roasts:
American roasts and lighter roasts should be done in about 4 minutes total time – just after first crack.
City roasts should take about 5 minutes total time, and be dumped out into the colander JUST at the beginning of the second crack.
Darker roasts can go as long as 6.5 minutes, but any longer than that risks burned beans.