Basic guide to roasting coffee in a popcorn popper
There are many brands of hot air poppers on the market, but unfortunately none are designed to roast coffee. With this in mind you must take care to select the proper units. When selected and used properly your hot air roaster will roast many batches of coffee. First, most new popcorn poppers will not get hot enough to roast coffee, so you’ll need to find an older version. Second hand stores and garage sales are a good place to start. Second, units that have air vents along the inside wall of the roasting chamber are preferred as they don’t require modification. Poppers that have a mesh screen on the bottom of the chamber require modification and have the potential to catch on fire, they are not recommended for roasting coffee. A list of poppers that we know will work can be found here.
Here is a video that shows the entire roast process:
Optional thermometer, Container (I use a cardboard box cut to fit the roaster) to catch the chaff, large spoon, colander (aluminum is best) 2 is better than one. Of course, don’t forget the high quality green coffee beans.
Setup your roaster in a well ventilated and well lit area such as under your stove vent hood, or next to an open window. The light is to help judge the color of the beans, and the vent is for removing the smoke. Have all of your accessories nearby, things can happen quickly.
Measure out coffee beans the same way the manufacturer suggests for popcorn, usually around 1/2 cup. Roasters vary, as do the coffee beans, so sometimes you’ll have to play around with the amount of coffee your roaster can handle.
Place lid back on roaster, position the chute over your chaff container and turn it on. After this point NEVER LEAVE YOUR ROASTER ALONE! They’re devious little suckers and will burn the coffee or your house.
There are a lot of variables that come into play here, ambient temperature, humidity, roaster specifications, but in general you should have roasted coffee in 5-10 minutes. The first couple of batches you may want to stand and watch the whole process, smell the different smells, see the colors and hear the cracks. After some practice you’ll be able to judge where you are by these indicators.
Listen for the cracks. First crack should happen 3-5minutes into the roast, with the second crack following shortly after that. Coffee is drinkable anywhere between the cracks, and sometimes beyond. Play with it and see where your preferred roast level is. Remember, this time it’s about you and what you like.
A few seconds before your roast level is achieved shut off the roaster and pour the beans into the colanders (careful they are HOT!) stir, toss, do what you can to cool the beans down quickly. They will continue to cook until cool.
Smile, you’ve just roasted coffee.
You can brew your coffee immediately but it is best if you allow the coffee to rest for at least 12 hours. The first couple of hours after roasting the coffee will be off gassing and it’s best to leave the coffee in a container that allows it too breathe. After the first couple of hours move the coffee to and airtight container until you’re ready to use it.