The physical requirements for roasting coffee correctly are very simple: The coffee needs to be kept moving in air temperatures of at least 400°F, and must be cooled at the right moment. There are many ways to meet these requirements in home kitchens.
They can be divided into four main approaches: 1) in the oven; 2) on top of the stove; 3) in a hot-air popcorn popper; and 4) in a small, commercially produced electric home roaster. Those who wish to experiment with one of the first three methods should purchase Ken Davids’ Home Coffee Roasting: Romance & Revival, published by St. Martin’s Press, and available in numerous online book stores.
Here, however, are a few words of advice and instruction in regard to the fourth and easiest alternative, commercially produced home roasting machines. Most of these devices work on the fluidized bed principle outlined earlier, meaning the beans are simultaneously heated and agitated by a column of hot air jetting up through the roasting chamber.