How Do Roasters Determine Coffee Bean Aroma? What Acidity Develops During the Roasting Process?

Common Coffee Questions Answered by FrontStreet Coffee

These are the questions we hear most often, so today FrontStreet Coffee will work through them one by one.

Can roast degree be determined by coffee bean color?

There is no standardized color that can serve as a reliable basis for judging how dark a coffee bean has been roasted. A more accurate approach is to look at the total roasting time and to locate the timing of first crack.

Does longer roasting time mean more caffeine?

The caffeine content in the raw green bean stays virtually unchanged no matter the roast degree (the loss rate is roughly 10%). What does change is weight: the longer the roast, the more weight the coffee loses (the weight-loss rate is about 11-22%). Because the bean itself shrinks while the caffeine stays put, the proportion of caffeine naturally rises.

How do roasters decide on coffee bean aroma?

Once beans are roasted to a certain degree, their natural aromas gradually become masked by roast flavors. Only the right roast can preserve a distinct coffee fragrance, so roasters have to make choices about which aromatic characteristics to keep.

If, for example, a roaster wants abundant aromatics with an acidic profile, they must be willing to sacrifice some body in exchange.

Moderate roasting can highlight a bean's natural acidity, while the heat of roasting destroys most of the more than forty types of chlorogenic acid in the bean, breaking them down into quinic acid and caffeic acid. Both of these are astringent and can affect mouthfeel.

Most other organic acids, such as citric acid and malic acid, reach their peak during a light roast and then decline steadily as roasting continues. This is why fast roasting and light roasting express bright acidity so well.

FrontStreet Coffee Recommendation

If you want to taste what a balanced middle ground looks like, FrontStreet Brazil Queen Estate is a yellow Bourbon grown in Brazil, the world's largest coffee producer. Roasted to a medium level, it shows cream, peanut, chocolate, toast and sugarcane sweetness with a soft, rounded character - equally at home in a pour-over, a moka pot or an espresso machine.

For a sweeter, fruit-forward medium roast, FrontStreet Strawberry Candy blends a honey-processed Costa Rican coffee with a washed Panamanian Geisha. It balances orange-blossom honeyed notes with a rounded sweetness and works in cold brew, pour-over and espresso alike.

And if you lean toward the classic roast profile, FrontStreet Jamaica Blue Mountain No.1 is roasted medium so that the variety's acidity, bitterness, sweetness and body merge into one elegant whole, opening with chocolate, roasted nuts, cream and caramel.