The Right Roast: Getting the most flavor out of a coffee bean

Dunn Brothers roast master Bob Vaseleski describes how roasting develops flavors in coffee beans // Photo courtesy of Dunn Brothers

The coffee we drink comes from the seed of the coffee cherry, commonly called a bean despite its not actually being a legume. That’s just one of many facts often overlooked while clumsily sipping that cup of light roast in the morning rush to get to work on time. Though coffee is firmly a part of many people’s morning ritual, most still don’t truly know what makes a flavorful cup of coffee, opting rather to leave the science to the men and women who grow and roast coffee.

Dunn Brothers opened its first location on Grand Avenue in 1987, and has had a hands-on approach to roasting and brewing its coffee since day one. Each of the company’s 85 locations and franchises today has its own roaster to maintain freshness and the artisan nature of the product. The beans come from across the world, whether Ethiopia or El Salvador, shipped to Dunn Brothers and then roasted on-site to give a distinct flavor that can range from fruit and berries to the toasted sugars of creme brulee or chocolate.

The Growler was on hand for a roasting tutorial featuring a new coffee bean, Santa Ana, Dunn Brothers is sourcing from Las Nubes Farm in El Salvador. Like all coffee, Santa Ana’s flavor starts with the raw bean—er, seed—which is shucked from the coffee cherry. Dunn Brothers hopes to highlight the differences that the natural drying process (often practiced in poorer regions of the world) and the wash process, which mechanically separates the pulp from the bean, has on the finished flavor of Santa Ana by releasing both versions. In general, naturally processed coffee carry more sweet, smooth, and earthy notes, whereas the wash processed coffee can be cleaner, brighter, and fruitier.

The beans are then shipped to a roaster, still containing trace moisture, roughly 10–15%, says roast master Bob Vaseleski, who roasts multiple 35-pound batches per day. The roaster at their flagship Freight House store looks like a giant 1960s piece of kitchen equipment, standing roughly six feet tall with a dull seafoam green coat of paint. Beans are dumped into a large funnel-shaped hopper at the top of the machine, where they wait before being transferred down into the roasting drum when it reaches the desired temperature.

The roaster at Dunn Brothers’ Freight House location // Photo courtesy of Dunn Brothers

Vaseleski uses roasting software, input to the machine via a USB drive, and a trained ear and nose to monitor exact timing and temperature for an exact process. The roasted flavor he creates comes from controlling temperatures between the first crack and second crack of the beans, sounds that are similar to popcorn in the kettle. The first crack releases sugars, while the second crack indicates the internal temperature of the beans themselves. Flavors created before the first crack are toasty and basic. The more nuanced flavors come after, as the sugars are caramelized in the Maillard reaction. It takes time to get the first crack, but between first and second it is a matter of mere seconds. Once fully roasted, the beans are dropped from the drum into the cooling tray where air is drawn the beans as they are stirred. It’s important to cool the beans as fast as possible to prevent further changes to its chemical makeup.

There are over 200 chemical compounds inside a green coffee bean and roasting creates a chemical reaction that can increase the number of compounds to nearly 1,000, says company co-CEO Skip Fay. The roasting process is a matter of manipulating or controlling those reactions and capturing a specified profile at a given temperature and time. And in roasting coffee, it’s important how that temperature is achieved. “It’s science with art,” Vaseleski explains simply.

Dunn Brothers’ Santa Ana coffee beans cooling after roasting // Photo courtesy of Dunn Brothers

Like beer, spirits, and all matters of beverage, the finished product is complex and relies on craft and consistency. Each Dunn Brothers employs its own roaster, who uses the software profile Vaseleski creates to match his recipe. The grind of the bean, the water used, and the method of brewing matter as well. For making coffee at home from freshly roasted beans, Vaseleski recommends a French press. A perfect flavor, he says, will come two to three days after roasting, once carbon dioxide levels have evaporated but before the subtleties are lost in maturity. Dunn Brothers, he notes, sells all house-roasted coffee within five days as a matter of policy.

Dunn Brothers’ new Santa Ana coffee is one they’re excited about. From meeting the growers at Las Nubes Farm in El Salvador to roasting the heirloom Bourbon coffee they’ve been growing for nearly a century, Dunn Brothers has been hands on at each step of the process to create two flavorful and distinct coffees from the same bean.