What Happens When Coffee Beans Are Roasted?
When you hear “green bean,” you probably think of the vegetable… unless you work in the coffee industry - then you know that the “green bean” is actually used to describe what your coffee beans look like before they are roasted. Yes, your coffee beans start out a light, creamy green color and during roasting develop their dark brown, chocolatey color. Let’s talk about what happens when your beans are roasted, and how we know when the roast is officially ready for your cup.
First, we load the green coffee beans (the raw, unroasted beans) into a special cart that weighs them to make sure we have the right amount for each batch. From there, a vacuum system moves the beans up into the top of the roaster, where they drop into the roasting chamber. This is where the magic happens!
At Alma, we use Loring roasters, which work a little differently from traditional coffee roasters. Instead of heating the beans through direct contact with a hot metal drum, Loring roasters use hot air to roast the beans evenly while internal paddles keep them moving. This helps create a more consistent roast while reducing the risk of scorching the beans. Even better, the roaster recirculates its hot air and uses a single burner to heat the air while also burning off smoke and chaff (the thin, papery skin that comes off coffee beans during roasting). This system uses significantly less fuel and produces fewer greenhouse gas emissions than conventional gas roasters.
As the beans roast, they go through three main stages. First is the drying phase, when the remaining moisture inside the beans evaporates and their color changes from green to pale yellow. Next comes the Maillard phase, when heat triggers reactions between the beans' natural sugars and proteins, turning them brown and creating many of the aromas and flavors we associate with roasted coffee, like toasted bread. Finally, we reach the development phase, which begins when the beans make a sound called first crack. This is similar to popcorn popping and signals an important change inside the beans as they roast.
During this final stage, our roasters carefully monitor the beans' color, smell, and sound. They use a tool called a trier (the small handle you may see them pull from the roaster) to take out a sample and check how the roast is developing. The timing of when the beans come out of the roaster makes a big difference in the final flavor. A shorter roast can bring out brighter, fruitier notes, while a longer roast can develop deeper, richer flavors like chocolate and caramel. Darker roasts may even reach a second crack. Every batch is carefully monitored so our roasters can bring out the best possible flavors in each coffee.
