Home roasting coffee does not need to be expensive or complicated. I have a simple guide to show you how you can easily roast the freshest coffee possible, and save some money too.
You can find these types of hot air popcorn poppers anywhere that sells small kitchen appliances, thrift stores and many outlets online. The main thing to look for is a flat bottom inside the heating chamber; you do not want the type with a raised mesh bottom due to the chaff settling and creating a potential fire hazard.
Be forewarned, roasting coffee in a popcorn maker is certainly outside of it’s designed use, so the warranty will be voided and the lifespan of the popcorn maker will be shorter than what it would be normally. Even with these caveats, this is still a very popular and affordable method.
There are multiple places online to buy “green” coffee beans. A quick search online is all it takes to find one you like. All the sites give descriptions of the different single origin and blends they sell, and this is a great starting point if you do not know the type of coffee you want, or looking for something new. If you have a local coffee roaster, you may be able to buy green coffee beans from them as well.
Once you have your raw “green” coffee beans and popcorn popper, you will need a bowl or sheet pan to cool the beans once they are out of the popper and also a place with good ventilation. There is quite a bit of smoke and chaff (the papery outer layer of the coffee bean that flies off during the roasting process) so this is best done outside if at all possible. If you must do it inside, make sure to be near an open window or exhaust hood and use a bowl to collect the chaff.
I use the butter warmer tray built in to the clear plastic top of the popper as a measurement tool for the green coffee beans, which equals to about 1/2 cup. I place the beans in the machine, put the cover on with the butter tray inserted, and then turn on the machine. You will need to gently shake the machine in a circular motion to keep the beans moving at first. Within 3-4 minutes, the chaff will start flying out and the beans will begin to lighten as they lose moisture. At this point, you begin will hear what is called “first crack” which is a snapping sound the beans make as the moisture expands and cracks the bean. Usually by now the beans are moving without assistance, so you can just sit back and watch and listen carefully.
Once the coffee completes first crack, it is a very light roast and can be used any time beyond this point. There will be a second crack with a more subtle popping sound usually 5-7 minutes after the first. This is where your personal preference, brewing method and coffee type can influence the level of roast. I personally prefer a medium-dark roast for espresso, so I roast until I just begin to hear the second crack, and depending on the coffee type, is usually between 10-15 minutes with this method. A medium roast will end somewhere between the two cracks, and a dark roast will go completely through second crack. This is actually difficult to do with this machine as it does not get quite hot enough, but this also provides a safety net so you do not have to worry about burning the coffee. If you prefer a very dark roast, a dedicated coffee roaster will be your best option.
Once the coffee is roasted to your liking, very carefully (the machine will be very hot to the touch) pour the beans into a sheet pan or large bowl, and allow to cool. The coffee can be used immediately, but the taste is better if it has a chance to rest for several hours or overnight. You want to store them in a container with a loose lid for the first few hours as the beans emit carbon dioxide as part of the resting process.
The coffee will last for about a week before you can notice a drop in flavor, usually losing the brighter flavors with less intensity, and sometimes gaining bitterness. You can also do several batches in a row if you prefer, just keep in mind to let the machine cool between each one so it doesn’t overheat. Please let me know your thoughts and experience with home roasting, and please subscribe for more content like this!