Reading Your Coffee Bag Part 3: Roast Level
Light, Medium Dark. What’s the difference?
Whereas parts one and two of this series focused on things that happen at origin, roast level is where Boomtown gets to put its own signature on the coffee supply chain.
Roasting coffee is just like cooking.
If you’ve never seen it before, “raw” coffee is actually green in color, and smells nothing like the coffee you smell at home (it’s kind of hard to describe, but the closest we can think of is underripe bananas). In the roasting process, we take raw, green coffee beans and turn them in this big, barrel-shaped roaster. The roaster has several probes inside to give us temperature data on the coffee. This data gets spit out onto a computer screen, so we can track its changes over time and compare roasts to see how consistent we can make them.
Roasting is required to make coffee drinkable. Essentially, darker roasts are coffees that are cooked longer or hotter.
The roasting process imparts flavors (just like cooking does), especially the browning of sugars in the coffee beans to get caramel and toasted flavors (the “Maillard Reaction”). Roasting too long can cause the coffee to take on burnt, smoky flavors. Roasting too light can cause the coffee to taste vegetal and grassy, because the green coffee beans haven’t been cooked long enough for the flavors to develop.
In general, lightly roasting coffee is favored to highlight more delicate flavor nuances (especially fruitiness and florals found in Ethiopian coffee), while roasting darker is chosen for coffees where that sugar-browning/caramel flavor can most compliment the coffee (South American coffees with chocolate and nutty flavor notes).