Coffee doesn’t start out as a delicious cup of coffee. There is a long process and many people involved to bring you that cup of coffee. Rather, coffee actually starts out as a cherry (fruit). The cherry is picked and the fruit removed revealing the wonderful coffee bean inside. These beans are packaged and sent to a roaster.
When the roaster receives the coffee it’s green. The roasters have the pleasure of taking the green coffee and roasting it until it is the desired tasting profile. Prior to roasting the coffee bean is pale and green-ish yellow and after it comes out with a chocolatey finish.
Tasting profile and roast levels are closely related. Most consider the tasting profile in terms of light, medium, and dark, but the problem with this is that the profile is not highly accurate. There can be significant differences between how two lightly roasted coffee beans taste.
The reason for this that each coffee is very different. Based on the soil, altitude, acids and sugars present within the coffee, the tasting profile may drastically change.
The roasting process starts with an analysis of the coffee itself. You must understand the base profile of the coffee bean. Once you understand the base acids and sugars present you can then predict how it will taste after roasting.
Here is where the roast profile is built. Everything is charted, measured, and customized based on that coffee. Which leads us to the three stages of roasting: Drying, Yellowing/Browning and Caramelization/Acid Development
The still-green coffee beans are added to the pre-heated roasting drum. Green coffee beans are often times either submerged in water or very moist prior to roasting. So drying is essential.
Once the coffee is dried, the heat of the roaster begins to “cook” the coffee beans. Cook is a loose term here. What is actually happening is the coffees natural sugars (like sucrose) are being broken down and developed by the heat. This along with the water turns to gas inside the coffee bean. (See Myth 2).
As the gas builds up the pressure causes the beans to grow in size and turn from a yellowish color to a brown color.
The pressure will build up to the point the coffee literally cracks. After this “first crack”, the coffee is in a critical state. The acids and sugars are in a delicate state and the roaster must be attentive to their coffee as it caramelizes. A balance between the acid and sugar must be struck and you strike the balance by timing the roast perfectly. If you wait too long, the caramelized sugars will burn and result in a second crack which means that the coffee has been fully burnt. Not waiting long enough and it will taste acidic.
The roaster will experiment with the roast level, time and intensity. Careful analysis and charting are done with each batch of coffee until the optimal and desired tasting profile is achieved.