Home Coffee Roasting 101
Why go through the bother of roasting your own coffee beans when premium whole roasted coffee beans are readily available in supermarkets and coffee shops throughout the Northwest?
Because nobody knows how you like your coffee better than you. With a little know-how and DIY inspiration, you can choose exactly the blend of coffee beans and degree of roast—light to very dark—to create your own ideal cup.
There’s also the issue of freshness. Unless your neighborhood espresso bar roasts its beans on-site, there’s a good chance they were roasted several days—even months—before they were brewed. Properly stored, unroasted coffee beans keep for months, even years, without losing their flavor, whereas roasted coffee beans go stale within a week or two. It’s the same difference between using freshly toasted and ground spices versus the old cinnamon sticks that you pull out of the cupboard only once or twice a year.
Plus, green coffee beans cost less per pound than the price of already roasted coffee, so you can save 10% to 60% or more, depending on the type of beans you purchase.
Home roasting can be easy, or it can be as exacting and technical as the geek in you wants to get. You can be old-school and roast in a skillet, or buy a fancy appliance. A number of home roasting devices are available, ranging in price from about $70 to $1,000, but “the truth is,” says Mark Prince of coffeegeek.com, “you can roast really great coffee in the home with a $30 investment in a popcorn popper and a candy thermometer.”
Hot-air roasting uses the same cooking principle as the electric hot-air popcorn popper, which is why some home roasters adapt these machines for roasting coffee. Hot-air roasters blow off roasting smoke and roast beans rapidly owing to an efficient transfer of heat. Hot-air roasting takes ten minutes or less, roasts very evenly without scorching, and is the ideal method for roasting a relatively small volume of green beans (three to four ounces). Hot-air roasters are also fairly inexpensive, ranging in price from $65 to $150.
For the home coffee roaster who dreams of radiant drum roasting with a Probat, the Cadillac of professional drum roasters, there are a couple of miniature, simplified versions of the classic machines. These industrial-looking machines have an aesthetic appeal certain to impress your friends, and they are capable of roasting more beans per batch—around a half-pound at a time—than other dedicated home roasting devices. Beans take longer to roast, producing a round, medium- to full-bodied cup, but the two major disadvantages of drum roasters are cost ($300-$600) and smoke. Drum roasters produce more smoke simply because they roast more beans, so before buying one make sure you have adequate ventilation.
Stove-top roasting—stirring the beans in a pan over heat—is undoubtedly the most traditional and still the most practiced method in many parts of the world, from Ethiopia and Latin America to Indonesia. For the cost of a pan, wok, or one of the covered, old-fashioned corn poppers, you can roast coffee beans. On the downside, results are often less than uniformly successful. If at first you burn your beans, try, try again.
Oven roasting is another low-tech approach, requiring no special equipment besides a perforated baking pan, oven mitts, a colander for cooling your beans, and, of course, a gas, electric, or convection oven. You can roast up to a pound or more of coffee at a time in an oven. Keep in mind, though, like stove-top roasting, achieving an acceptable roast requires patient experimentation.
The Roasting Process
Once the beans are in your roaster of choice and the heat is on, your ears, eyes, and nose will tell you how your roast is progressing.
During the first few minutes the beans change in color from green to yellowish brown. As the color changes, you might be able to detect light aromas such as grass, bread, burlap, or sweet barley.
As the beans start to turn light brown and begin to smoke lightly, listen for the tell-tale “first crack”—a rather loud popping or cracking sound similar to a crackling fire. This is the moment when the roast transformation begins: the beans have heated up to around 420?F, sugars in the bean begin to caramelize, bound-up water starts to escape, and the structure of the bean begins to break down.
Once the beans turn from light to medium brown and the cracking reaches a crescendo, the beans have become lightly roasted—also called “city roast” style. If you like your coffee slightly acidic and sweet, with subtle tea and grain flavors, stop the roast at this point.
If you continue to roast until the crackling fully ceases, the roast smoke may begin to darken slightly and smell sweeter. Stopping the roast at the end of the first crack produces medium brown beans with a bright, classic “breakfast” style, medium-roast cup.
Continue past this point and you’re headed to the “second crack,” which has been likened to the sound of paper being crinkled. The roast smoke continues to increase in volume and becomes sweeter and more pungent. Roasters who stop the process just at the beginning of the second crack call these beans “full city” or “Viennese.” These beans will brew a full-bodied cup with roasty but not burned flavors.
After this point, you have entered the realm of dark roasts. The beans turn dark brown, and the crinkling sound becomes almost continuous. The smoke thickens, becomes dark, and smells intensely pungent. The flavor characteristics that are produced at the second crack and beyond tend to be quite different from those at lower temperatures—smoky, woody, or even asphalt-like.
Keep roasting and chances are you’ve gone too far! At this late stage of the roast, the beans turn black and the coffee’s
aromatics will have literally and figuratively gone up in smoke.
Home Roasting Resources
For obvious reasons, local coffee roasters are not very obliging when it comes to selling green beans to wannabe roasters. Your best bet is to visit an online retailer such as sweetmarias.com.
Coffee Wholesalers (coffeewholesalers.com), based in Eugene, OR, focuses on organic coffee beans and also sells a selection of home roasting equipment.
You can also find green beans at Bridgetown Coffee (3460 NW Industrial St., Portland, OR, 503-224-3330), or Thorn Tree Coffee (thorntreecoffee.com), a Beaverton, OR-based seller who specializes in coffees from Africa.
Green coffee beans are not stocked on the shelves at many, if any, mainstream supermarkets. You’ll have better luck finding them at ethnic food stores, such as Selam Market (3513 NE Martin Luther King Blvd., Portland, OR, 503-288-8585) and Taste of Europe (1739 SE Hawthorne Blvd., Portland, OR, 503-238-3693).
To link up with other DIY coffee enthusiasts, check out the compendium of coffee topics and discussion areas at coffeegeek.com. Moderated by Vancouverite Mark Prince, the Web site features product reviews, how-to guides, and user forums for sharing home roasting tips.
By Peter Szymczak
From our January/February 2009 issue.