The Art of the Roast

Checking the color of the coffee beans during the roasting process.

We are pleased to welcome a new critic, Ellen Perry, to our group.

On June 18, 2007, David Fullerton taught his last high-school English class and went into the coffee business. He had purchased a café on Main Street in Worcester, Massachusetts – put it on his credit card, in fact – and launched a new roasting operation. He decided that he liked the name the previous owners had given to the café, Acoustic Java, so he kept that – though any connection to music is, at this point, largely metaphorical. But Fullerton likes literature and appreciates a good metaphor: Acoustic Java’s motto is now “As music tames the savage beast, coffee civilizes man unkind”; and its coupons look like concert tickets.

On a January morning, I’m sitting with Fullerton at his second Worcester location, a building that used to be part of the Whittall Mills, a 19th-century carpet company. It’s a typical New England mill, so the roasting area is enormous, and the ceilings are high and supported by sturdy beams. By contrast, the adjacent tasting room is cozy, its brick wall lined with bookshelves and original art; but it also has a capacious view through plate-glass windows into the roasting operations. Fullerton wants to offer his customers “a spectacle . . . an authentic one.” He wants them to see something of what happens to their coffee before Patrick, the barista, pours it into their cup.

Fullerton has been roasting coffee since he was a graduate student at Brown, beginning, as so many home roasters do, with a popcorn popper; but the Whirlypop smoked too much, so he graduated to a one-pound coffee roaster – which also smoked, but could at least be vented out the window. Eventually, he brought that one-pound roaster to the original Acoustic Java café and his hobby became his vocation. Eleven years later, we’re sitting in front of an entirely different caliber of machine, a Loring roaster. The Loring is a sleek bit of industrial design capable of handling more than 70 pounds of beans at a go, and also capable of incinerating the by-product. So no more smoke. In 2017, Roastmeisters – the name of Fullerton’s roasting operation – handled something like 37,000 pounds of beans. The Loring roaster is essential equipment for an operation of that size.

David Fullerton with a rye barrel in which green beans are aging.

Beans come to the roastery from all over the world – Indonesia, Africa, the Americas. When they arrive, they’re dun-green, something close to the color of common lentils. I take a whiff of various unroasted beans and some of them have the aroma of hay, but as alluring as that might sound, unroasted beans don’t make a decent cup of coffee. They keep for a long time, but they can’t be brewed into anything you’d want to drink. Roasting brings out the coffee flavors we love; it also severely reduces the shelf life of the beans.

Roasting takes somewhere between 9 and 15 minutes. During that time, the beans change in color from their original dun-green to a sort of chestnut brown and then, if the goal is a dark roast, to the color of dark chocolate. Beans that are roasted for a relatively long time pass through two phases, called “cracks” after the noise that signals the initiation of each phase. Fullerton describes the first crack as sounding like popcorn and the second as sounding like breaking matchsticks, but the Loring conceals those diagnostic noises, so in order to control the roast he relies on other indicators like color, time, and temperature. During the first crack, the moisture in the bean turns into steam, builds pressure and rapidly expands: the bean itself actually puffs up. This is exactly what happens when you make popcorn, which explains why so many home coffee roasters have had smoky success with repurposed Whirlypops.

Sometime around the first crack, the beans begin to darken and sugars and complex flavors begin to develop. This is the magic that cooks and chemists alike know as the Maillard Reaction. The Maillard Reaction is why foods like roasted meat, freshly baked bread, and coffee turn brown – or browner. It also develops complexity of flavor: basically, it’s why roasted meat, freshly baked bread, and coffee are so delicious. So, once coffee beans have reached the first crack, they will produce a drinkable, even delicious, cup of coffee. If the goal is to produce a medium roast, the process might stop after the first crack. If the goal is a darker roast, the roaster keeps going, the temperature continues to rise, and the beans are allowed to reach second crack.

These days, Fullerton is experimenting with barrel-aging coffee beans in whiskey barrels – the sort of thing that sherry makers do. Green beans are hard but absorbent, so he ages them for at least a month, and stirs them in the barrel weekly. He tried aging coffee beans in wine barrels from a local vineyard but discovered that they don’t do much for the flavor of coffee beans. Whiskey is a different matter. Whiskey leaves its mark. He’s had success with barrels that once held Blanton’s bourbon and barrels that once held Four Roses bourbon. His next experiment is with Sagamore Spirit Rye.

You might think that the perfect cup of coffee would come from grinding the beans as soon as they’re roasted and brewing them on the spot; but the carbon dioxide and other gases that have formed in the beans during the process need to dissipate or the flavor will be erratic; and so the beans need to rest and degas. The industry standard for degassing has been 24 hours, but emerging research suggests that the ideal cup of coffee might require allowing the beans to degas for a week. Evidently, there’s still room for debate. Just don’t try to brew a cup of coffee the moment you’re done roasting the beans.

Fully roasted coffee beans.

The necessary follow-up to roasting is cupping – which is a bit like wine tasting, but is meant to introduce another degree of quality control to the process: its main purpose is to screen for defects. Today we cup 3 kinds of coffee from Burundi – Karehe, Gitwenge 1307, and Gitwenge 1308. All 3 were roasted a few days earlier and so have had time to degas. For each coffee that we’re tasting, Fullerton puts out 3 cups. One is for the coffee itself and one holds water for rinsing the tasting spoons. (I’ll find out the purpose of the third cup later.) Into the first, Fullerton measures 14 grams of coffee and instructs me to smell the grounds dry. He then pours 250 milliliters of hot water into the cup and grounds float to the top creating what’s called a crust on the surface. He shows me how to use the spoon to stir the coffee grounds (“break the crust”), smell again to get a sense of the wet aroma, and then get a clean spoonful of liquid. The third cup, it turns out, is for any coffee grinds that remain floating after the break and wet aroma assessment.

And then I slurp – a loud and deliberate slurp, in contravention of everything my mother ever taught me about how civilized human beings consume food and drink. Slurping aerates the coffee and allows it to spray across the palate, so it enhances tasting. I’m supposed to form judgments about the acidity, aftertaste, body, and flavor of the coffee, all of which Fullerton is able to do at once – and I am not. Fortunately, he used to be a teacher and so he breaks that daunting job down into component parts for me – asks me to say something about the acidity of each coffee first; then the body, and so forth. When we get to flavor, I try out a few adjectives – this one is lemony, that one tastes like molasses. Those are the sorts of descriptors that might end up on the coffee bag – so it turns out that cupping isn’t just about screening for defects; it’s also about figuring out how to let customers know what they can expect to find in a particular bag of coffee.

There’s a curious relationship between knowledge and appreciation: after three and a half hours of learning about the arts of coffee roasting and cupping, I really can taste better. I know some of what to look for, and can actually distinguish among three coffees from the same region. Three and a half hours of learning is nowhere enough time to become an expert; but it’s enough to give me some sense of what to ask for the next time I order a cup of coffee.

– Ellen Perry eats, cooks, and keeps bees in central Massachusetts. She teaches classical archaeology at the College of the Holy Cross and is the author of The Aesthetics of Emulation in the Visual Arts of Ancient Rome, the co-editor of Roman Artists, Patrons, and Public Consumption, and has written a number of articles on Roman art and architectural space.