As consumers have become more interested in where their food comes from and how it’s grown or raised, this same curiosity has extended to coffee, its quality and origins, leading to the emergence of specialty coffee roasters.
That’s all led to a new interest in home coffee roasting, something commonplace hundreds of years ago. So, as someone who takes coffee seriously, I thought I’d see what it’s all about.
With so many great local coffee roasters, my first question was what’s the advantage, if any, of roasting at home?
As I discovered, it’s about learning the varieties and properties of coffee beans, the countries where they’re grown, and the roasting process itself. This adds a new perspective to consuming coffee. You also can access a much wider variety of unroasted green beans than what’s available elsewhere. And green coffee beans keep for a year, allowing one to always have freshly roasted beans.
While there’s a cost savings from home roasting — green coffee beans cost from one-third to half of roasted beans, that’s somewhat negated by the extra work it takes and the cost of a roasting machine.
Yet after a couple of months of effort, my espressos and cappuccinos are often better than those made from the beans I previously bought from the best of the specialty roasters.
To roast beans you need green coffee beans and, of course, you need a roasting machine. For beans, I turned to an Oakland company, Sweet Marias, (sweetmarias.com), which sells a wide variety of green coffee beans from dozens of countries, and is one of the leaders in the home coffee roasting movement.
The company offers about 70 varieties of green coffee beans, priced from $5 to $7 per pound, as well as a wide range of roaster equipment. Each coffee varietal and blend is described in depth on the website, including how and where the beans were grown, along with detailed tasting notes. The very informative website explains essentially everything else you need to know. Sweet Marias got me started with a sampling of a few coffees from Africa, South America, Central America and Asia, and I bought another half-dozen varietals and blends.
For roasting, you can use something as simple as a cookie sheet or an air popper, but you are much better off with one of the coffee roasting machines that are designed to let you control the temperature and time (the roasting “profile”), which provides uniformity and repeatability of roasting, so you can better control the process.
Before selecting a roaster, I spent hours reading reviews and downloading user manuals of all the equipment available. I selected the Gene Café Roaster, available from the importer (at batchcoffee.com), Sweet Marias and elsewhere. It’s midpriced among the available home roasters at $515, with others ranging from $250 to $1,000.
The roaster is the size of a large breadbox; it has a base and a removable roasting chamber, a transparent cylinder that holds the beans and rotates continuously at an incline during the roasting process, keeping the beans in continuous motion. Two knobs are used to set the time and temperature. The cylinder provides excellent visibility to the beans as they turn from green to cinnamon color and finally to their completed state of medium to a deep brown. You use the color and some audible cues to determine when the coffee is done.
The Gene Café roasts up to a half-pound of beans at a time. Heat is supplied by a fan that blows hot air through the cylinder and, at the same time separates the loose hulls from the beans and collects them in tray. The entire roasting process takes about 15- to 20-minutes and then goes through a 5- to 10-minute cooling process.
You control the temperature and time and can make adjustments throughout the cycle to vary the roasting conditions, giving you great flexibility. Few experts seem to agree on the temperature versus time profile; much of it is trial and error, and varies by the bean and the size of the roast. I found setting the temperature to its maximum, 482 degrees F, provided good results. In fact, the temperature reaches that level only at the very end of the roast.
To determine when to stop depends on the kind of roast you want. Roasting is completed anywhere between the end of what’s called the “first crack” to a minute or two past the beginning of the “second crack.” The first crack occurs about 10 minutes into the process, as the beans turn from cinnamon to a medium brown, and you hear a succession of pops, much like a popcorn machine, but more subdued.
When the pops are completed, you have reached a City roast. Additional roasting will lead to the beginning of more pops a minute or two later, called the “second crack.” Just before this occurs is a Full City roast. And at this point, when the second cracking begins, is a Full City+ roast. Roasting after the second crack results in a dark Vienna roast, often appropriate for espresso. Beyond that, the coffee begins to burn and loses many of its good characteristics.
You can use most bean varieties for either coffee or espresso, but espresso is usually roasted closer to the second crack. And some beans are better for one or the other. The beans you buy usually recommend at what level they should be roasted.
As the coffee is roasting, smoke comes out of a small chimney, so it’s best to do the roasting outdoors, under a vent in your kitchen, or with a dryer hose running from the chimney out a window. The smell of the smoke is somewhat pungent and unlike the smell of fresh ground or freshly brewed coffee. Because of the high temperatures, all of the roaster machines recommend that you watch over the process and not leave it unintended.
Once the roasting is completed, you want to allow the beans to rest in a vented container to allow outgassing, and not use them right away. Wait a few hours before making coffee and about a day before making espresso.
As a newcomer, I ran into a few problems. I forgot to clean the chaff out after the first few roasts, blocking the air exit vent, and a subsequent roast had trouble reaching temperature from the lack of airflow. It also resulted in oils emitted from the beans, coating part of the roasting chamber that were a chore to clean.
Among the nearly two dozen roasts I did, I burned a batch just once. Everything else I roasted, including beans for coffee and espresso turned out pretty well. Most of the variation was from the coffee beans themselves. I kept a notebook of how each batch was roasted so that I could experiment and adjust some of the variables.
While coffee roasting is not for everyone, if you do love coffee, you’ll learn so much more by going through the process and getting exposed to a wide variety of specialized coffee that’s otherwise unavailable. I found the coffee roasting to be fun, educational and it provided me some of the best coffee I’ve ever had. I plan to continue to roast my own coffee.
While I was enthusiastic about the results, my wife was even more so. She was able to find beans, both caf and decaf, that met her goal of being medium-strong with no acidity at all.
Baker is the author of "From Concept to Consumer," published by Financial Times Press. Send comments to firstname.lastname@example.org. Comments may be published online or as Letters to the Editor.