Variety, origin, altitude, soil-type, farming, processing, and brewing. They all affect how the coffee would end up in your cup. However, if there’s one factor that has a huge influence on the beans, it’s the roasting process.
Roasting coffee beans has been around practically ever since civilisations have found out that they can get some fine, potent drink out of the cherries from these coffea shrubs. From heating the peeled beans over an open flame, the roasting process have taken up many refinements over the centuries. Today, coffee roasting is heralded as both an art and a science. This is because it’s easy for an unskilled roaster to ruin a lot, and it takes a great deal of experience, calculation, and that elusive roaster’s “6th sense” to really bring out the distinct essence of any green coffee bean.
Now let’s take a deeper dive into the coffee roasting process and how exactly it affects the brews that you enjoy day in and day out.
Coffee Roasting Process
Coffee roasting is quite like cooking. In the same way that a chef must gage the doneness of the food on the stove using all his senses and be careful not to over-cook, a roaster also has to keep a close eye (and ear, and nose) on the beans, from the time it hits the heat until it goes through the different phases of the roasting process.
Before the process even begins, the roaster has to do his homework about the beans he is going to roast. This allows him to create a roasting profile that will best highlight the best qualities of the beans. Afterwards, the roasting begins.
- Drying (00:00 – 03:00). This is the first stage of the roasting process. At this point, the coffee is green and, after wet or natural coffee processing, may contain between 10 and 12% water. This amount of moisture must first be driven away as you heat the beans, usually 3 minutes into roasting.
- Yellow to Light Brown (03:00 – (08:00). After drawing out the water completely from the green beans, different changes start to take place as the beans’ color changes to yellow or even to light brown. This shows that the sugars within the beans are breaking down as the chemistry within changes. There will also be a grassy or toasted grain aroma coming from the roasting drum.
- First crack (08:00 – 08:30). Heat pressure from the beans builds up and tries to escape, resulting to the first crack. Here, the beans burst, and this can be heard as a clear popping sound. You will also notice that the beans have expanded as it releases heat. This first crack stage is short-lived as the beans absorb and give off heat, making the roasting process from here on very critical.
- Development (08:30 – 10:00). This is the most important roasting stage, as many chemical changes happen to the beans, greatly affecting its aroma and flavor. If the development stage is too long, the beans can turn acidic. Too hot, and the beans’ sugars will over-caramelize. It’s all up to the roaster’s intuition to determine how long he will develop the beans at this point to create roasting profiles.
Coffee Roasting Profiles
The roasting profiles are the following:
- City Roast (400 – 415 degrees F). This is the lightest roast of coffee and with this, you can still taste much of the beans’ origin character. This also has the highest level of caffeine. The longer the roast, the more this pick-me-up compound breaks down.
- Full City Roast (415 –445 degrees F). This is a little right before the second crack, or sometimes 10 seconds into the second crack as the beans’ cellulose further fractures. The beans will have a medium brown color.
- Vienna Roast (446 – 465 degrees F). Here, the origin character of the coffee will give way to its roast character, but the cup will remain full-bodied as it retains its aromatic compounds and oils.
- French or Italian Roast (475 – 510 degrees F). At this point, the beans turn a dark, rich brown color as the sugars caramelize. The beans still continue to expand, but the oils and aromatic compounds are also being cooked off, resulting to a thin cup.
- Spanish Roast (520 – 530 degrees F). This is when the aromatic and flavor compounds are highly degraded and the beans are close to catching fire. Here, the beans will have the third crack as it turns to carbon, resulting to a very thin, if not burnt-flavored, cup of coffee. Still, there are many expert roasters that were able to pull off this roast profile and come up with a sweet-tasting coffee with subtle acidity.
- End of Roasting. Once the roaster has finally gotten his desired roast profile, he will then quickly remove the beans from the roaster and cool them rapidly.
- De-gassing. The beans are also allowed between 15 and 24 hours to de-gas in a breathable container, usually bags with one-way valves. This allows the beans to fully develop flavor before they are prepared for brewing commercially or at home.
So there you have it. Whether you like a light or very dark roast, ultimately it’s about what tastes great for you. Perk has a great range of beans roasted from medium to dark for you to explore. You can also learn more about coffee on our blog – The Perk. Also, do check out these guys if you’d like to do some roasting of your own.