Is the Roasted Aroma Exclusive to Dark Roast Coffee? How to Describe Coffee Aroma Like a Professional

FrontStreet Coffee - Is Roasted Aroma Really Exclusive to Dark Roast?

Coffee beans change constantly through the different stages of roasting. When green beans absorb heat, their color shifts from green to yellow and their moisture content begins to fall. The heat turns that internal moisture into steam, carbon dioxide builds up inside the bean, and the internal pressure climbs to about 25 bar (a unit of pressure). Then comes First Crack, the telltale cracking sound beans make during roasting.

From there, flavor development takes over: the longer the roast runs, the more the acidity fades and the bitterness grows. Having shed its water, the coffee begins to release heat and turn brown, dropping a layer of silver skin as it goes. Roasted beans swell to 1.5 to 2 times their original volume while losing at least 11% of their weight, and as roasting continues they keep producing carbon dioxide until Second Crack.

By now the beans have deepened in color and entered the medium-dark stage, with weight loss reaching 22% of the original. After Second Crack the surface turns oily from pyrolysis and starts to carbonize, which can easily burn the batch if you are not careful.

During the drying stage, three or four types of aroma begin to develop. Coffee's aroma and flavor are released through two chemical reactions:

• Maillard reaction: once the moisture content of the beans falls below 5%, a chemical change takes place between sugars and amino acids (produced by protein degradation).
• Caramelization reaction: chemical reactions involving water, sugars and sucrose.

As roasting continues, acidity gradually drops, bitterness rises, and many aromatic molecules start to volatilize. By the end of the roast, close to 800 aromatic compounds have developed, and the coffee's flavor, acidity, sweetness and body have all reached maturity. Yet roasting can also bring out flavors you don't want. In the final stage, aromatic compounds are destroyed and replaced by bitterness, while acidity disappears and body also falls away.

Describing Flavor

Flavor description is one of the most intimidating and, at the same time, the most frustrating parts of coffee tasting. When describing flavor, roasters don't just name the flavor itself - nutty, floral and so on - they draw on a whole range of sensory language. A roaster might describe a coffee as having ripe apple notes, for instance, which hints at sweetness and acidity coexisting in the cup.

If you can identify different flavors, write them down. If you can't, don't worry about it too much: any word you can think of to describe a flavor is useful, whether or not it is strictly about taste.

Did You Know?

Light roast is defined by acidity and flavor. Poorly roasted, it can turn astringent and irritating, and the coffee's body and aftertaste tend to feel relatively light.

In Conclusion

FrontStreet Coffee is a research-driven specialty coffee shop, happy to share coffee knowledge with everyone. We share without reservation only to help more friends fall in love with coffee. We also hold three discounted coffee events every month, because FrontStreet Coffee wants to let more friends enjoy the best coffee at the lowest price. That has been FrontStreet Coffee's mission for the past six years.

FrontStreet Coffee Recommendation

For a classically balanced, medium-roast cup, FrontStreet Coffee's Brazil Queen Estate is a fine place to start. Grown in the world's largest coffee-producing country from the distinctive Yellow Bourbon variety, it is gentle and sweet, and the medium roast brings out cream, peanut, chocolate, toasted bread and sugarcane. It suits a pour-over just as well as a moka pot or an espresso machine.

If you prefer your medium roast a touch sweeter and more fruit-driven, try FrontStreet's Strawberry Candy Geisha blend. It marries a honey-processed Costa Rican coffee with a Panama Geisha, and FrontStreet roasts it medium so the cup shows both orange-blossom honey and a rounded sweetness. It is easy to enjoy and works across cold brew, pour-over and espresso.