I used to hate the taste of coffee. I loved the aroma of roasted coffee beans and fresh brewed coffee, but the taste of the black liquid was too bitter for me to want to drink. One time I was really desperate for caffeine and coffee was my only option, so I learned that mixing in a hot cocoa packet into the coffee made the taste tolerable. After that, I followed any new coffee drinker’s procedure of pouring in a cow’s worth of milk and 10 packets of sugar into my morning cup of joe. Eventually my taste buds adapted and I finally grew to like the taste of black coffee. The big turning point for this was when I went to Europe and would drink espressos multiple times throughout the day. After I returned to the United States, I chased the espresso flavor at home, trying to improve my morning cup of coffee by moving from a drip coffee pot to multiple French presses (they break easily), an AeroPress, and eventually I gave in and got an espresso machine.
Now I was finally happy with my coffee drinking habit, but I realized I kept chasing new flavors by getting coffee beans from around the world. I tried out all of the different styles I was interested in at the local grocery stores and decided to buy some beans from a local coffee shop that roasts their own beans. The beans themselves were fine but the thing that put me off was that the coffee roaster was selling these beans for $25 per pound! They were good, but definitely not good enough to be paying that price.
Coffee roasting became my new focus. How much do green (unroasted) coffee beans cost? Where do I buy them? Do I need special equipment to roast the beans myself? Is it worth the effort to roast them myself?
Fortunately, I found that a lot of coffee drinkers were roasting their own coffee at home with pretty inexpensive tools. At the most basic level, coffee beans could be roasted on a stove top in a frying pan or in the oven although they would generate a good amount of mess. By far the most popular way that people roast beans at home is with a $20 popcorn air popper. I bought myself a Nostalgia popper from Bed, Bath, and Beyond and ordered a 4 pound sampler pack of Kenyan coffees from Sweet Maria’s for less than $8 per pound shipped.
What is roasting?
The basic principles behind roasting beans is simple — heat the beans while constantly moving them until they reach your desired roast color. They need to be heated to about 450 degrees Fahrenheit and the constant movement ensures all of the beans are evenly roasted. The roasting process can be more complicated than that — holding beans at different temperatures for different amounts of time to develop flavors, improving the speed with which you cool the beans, etc… — but at its most basic level roasting only involves heating the beans evenly until they reach their desired color.
A popcorn air popper does a great job with roasting because the hot air keeps the beans constantly moving, ensuring a mostly even roast. When coffee beans are roasted, the chaff from the beans separates and the chute on the popcorn air popper does a great job redirecting the mess into the sink.
How to roast
1. Measure out your green coffee beans.
I use a scale to weigh my beans, but a measuring spoon will work too. For my air popper, 50g of raw beans is a good amount. At this weight, there are too many beans to zoom around the popper but there are enough so that the air pushes them at a slow crawl. Finding this “not too fast, not too slow” amount of beans for your popper is crucial for an even roast. The point of measuring out this amount is so that you can get consistent results every time.
2. Put the beans in the popper and watch them spin.
It’s good to have a bowl of water outside of your popper’s chute because a lot of airy chaff will float away from the beans. After a few minutes the beans will reach the “first crack”, an audible cracking sound (similar to popping popcorn). This first crack denotes the earliest lightest roast you can have with beans, called a City roast. At this point you watch the beans until they reach the desired color you are shooting for. After another few minutes, the beans will reach an audible “second crack” which means the beans are reaching a Full City + roast. At this point, a lot of steam might be released from the beans and your smoke detector might protest. You can continue roasting pass this stage for a Vienna or French roast, but since I don’t have any fancy equipment at the moment I have always been stopping my roasting at the first sounds of the second crack because it is an easy way to achieve consistency. This roasting process can get really complex (if you want it to), and I highly recommend doing more reading about it if you are interested: Sweet Maria’s Coffee Roasting Theory.
3. Cool the beans.
Immediately after your beans reach a desired roast level, quickly dump them out onto a metal baking sheet, colander, or sieve and jostle them around. We want to give the beans as much surface area as possible to allow them to cool as quickly as possible — using something metal also helps transfer some of the heat away from the beans. The reason we want to cool the beans quickly is because they just came from a 400 degree Fahrenheit popcorn popper and if they aren’t cooled quickly they may actually continue roasting outside of the popper.
4. Patiently wait.
After the beans cool you should ideally wait at least 4 hours before grinding and making coffee with them (this lets some of the CO2 dissipate). I like to store my beans in glass mason jars. For the first day, I screw the lids to the jars on all of the way and then unscrew them a quarter turn — this leaves just enough room for CO2 produced by the roasted beans to escape from the jar.
Roasting coffee beans is as simple as that. I’m able to setup, roast about .5 pounds of beans, and clean up in about 20 minutes. The coffee made from the beans is on par with the best coffees I can buy at any store or café, and being able to purchase raw green coffee beans online means the variety of coffees I can try is almost limitless. Although the process outlined above has given me great results so far, there is a lot of tweaking that can be done, like holding roasting temperatures between first and second crack for longer periods of time in order to produce different flavors in the roasts. Over time I plan on exploring some of these more technical options!