Whenever I tell someone that I roast my own coffee they look at me like I just dropped in from Mars and then they ask "How do you roast your own coffee? Isn't it hard?".
Roasting coffee yourself is easy. Really. If a person can make popcorn, they can roast coffee. There are many methods to roast coffee at home. There are even appliances dedicated to home coffee roasting. The method I use and will describe is with a hand crank popcorn popper. Some call it the "Whirly-Pop".
Required equipment: Coffee beans, popcorn popper, stainless steel colander, scale or measuring cups, a heat source and if indoors, a vent that pulls the smoke outside.
The first step is to acquire some green coffee beans. There are many sources to obtain green coffee beans. Some that I have used and like include Sweet Maria's, Cate's Green Coffee, Bald Mountain Coffee, Smith Farms (Hawaiian Kona direct from the farm), or Higher Grounds Trading Company. As you can see below today's batch is from Higher Grounds.
First, I put the "roasting vessel" on the stove to pre-heat. It takes a few minutes to get the pan hot enough. At this point it might be appropriate to mention that I am looking for good heat control, not just a lot of heat. Too much heat will scorch the beans, too little will bake them instead of roasting them. It's a balance that a person develops a feel for. Burning a batch or two on the way to getting the right amount of heat is common. The pan is pre-heated so when I drop the cold beans in, the pan can recover quicker and spend less time recovering.
While the pan pre-heats I measure out the beans I am going to roast and set them aside. Here I've measured out about 2/3 of a pound. For those without a scale this is a little more than 2 cups. Through experience I've found that is about what I drink in one week, so that's what I roast. Coffee will lose about 15-20% of it's weight while roasting. So, to end up with 1 pound roasted will require approximately 1.25 pounds green.
When the roasting vessel has pre-heated (the air just above the bottom of the pan should be about 350 degrees) and I have my beans measured out it's time to get roasting. I drop the beans in the roasting vessel and start cranking. No need to crank wildly, just crank constantly. It's important to keep the beans moving so they don't scorch.
About 4 minutes after dropping the beans in puffs of steam will start to appear. Soon after that the aroma will become very floral. After 6-8 minutes the aroma will become increasingly coffee-like and the beans will begin popping. The sound is something like the sound of stepping on a large stick when walking in the woods. This popping will continue for a minute or so. Then, all will become quiet again. This is what is known as first crack. A person could stop the roast here, dump the beans to cool and have a nice lighter roast. At this stage there will be more bean flavors and not many roast flavors. However, we can continue roasting.
After about a minute or two the aroma will change again to something best described as burnt toast. The beans will begin popping again. Only this time the popping is softer. It sounds more like walking through dried leaves. This is what is known as second crack. I usually stop the roast and dump the beans just as second crack gets started. This makes a nice medium-dark roast with plenty of bean flavor and some nice carmel notes starting to appear. If pushed farther, the bean flavors disappear and roast flavors completely dominate. If pushed too far, the beans will experience third crack, which is flaming.
Note that roasting coffee will generate quite a bit of smoke. It's best to roast coffee outside or under a vent hood that will pull the smoke outside.
To cool the beans, I dump them into a stainless steel colander. Why a stainless steel colander? Because the beans are about 440 degrees when coming out of the roaster. They would melt a plastic colander.
This batch I pushed a little farther into second crack for a somewhat darker roast. I stir the beans and hold the colander up to the hood vent fan to pull air through the beans to cool them quickly.
Once cooled I put the beans in mason jars for storage. I keep the mason jars in a dark spot in the cupboard where the temperature doesn't change too much. Light is as bad for coffee beans as it is for beer. While the coffee will be really good right out of the roaster, the peak flavor will start about 24-36 hours after roasting and hold for 7-10 days. After that the flavor will decay pretty rapidly.
It's important to note that the chaff will remain with the coffee using this roasting method. It doesn't hurt anything. Some other roasting methods will separate the chaff as the coffee is roasted. If the chaff is bothersome, take the colander outside and blow on the coffee while agitating it. Most of the chaff will blow off this way.