The Coffee Roasting Process

By no means is this post meant to be an extremely in-depth, technical look at the coffee roasting process. Rather, this is meant to be a somewhat high-level overview of coffee roasting and what happens from the green bean to the roasting to your cup.

Green Coffee Beans
Believe it or not, coffee beans are not really “beans” at all, but are actually the seed of a coffee plant which has been picked and dried by one of a few drying processes. Finding good quality green coffee beans from around the world is the first step to roasting great coffee.

Roasting Background
Many roasting companies roast ahead of time in anticipation of sales. These same companies also tend to roast every coffee they have exactly the same (no matter what origin and what roast level best fits the coffee). In fact, many of these roasting companies roast their beans extra dark to hide the stale taste of old coffee beans. Beware of any company who only roasts dark. That “burnt” taste they’re trying to sell you is not really how coffee is supposed to taste (with the exception of a few coffees that should be roasted dark (Vienna roast) on purpose for making espressos or because it’s the best roast profile for that particular coffee).

The Roasting Process
After finding the highest quality green coffees available, the roasting process can begin. Coffee can be roasted to many different roast levels. These levels (starting with the lightest to the darkest) are:

1. City/Light (first crack, a volatile sound of the beans cracking, has finished)
2. City+/Medium (shortly after first crack is complete)
3. Full City/Medium Dark (second crack is about to happen at any moment)
4. Full City+/Dark (the first few moments into second crack, a quieter snapping sound)
5. Vienna/Light French Roast/Very Dark (second crack is happening) – this is the darkest roast Weekly Roast offers (if we roasted any darker, the coffee would taste burnt and bitter)
6. French Roast/Extremely Dark (second crack is almost done) – Weekly Roast does not offer coffee this dark

When coffee is roasted, the bean undergoes a series of chemical reactions that transform it to its ultimate consumable state. Heat is applied to the bean through the roasting machine (there are many different roasting methods out there). We roast with a drum roaster and we use sight, sound as well as smell to determine when the coffee beans are done roasting. Roasting coffee is not a science, but rather an art, and it takes a lot of skill to know not only what roast level will bring out the maximum flavor, but also to know the precise moment during roasting when the beans have reached that level and stop the roast.

Here’s two pictures I took during some quality checking of one of our coffees: before roasting and after roasting to give you an idea of the before and after.

After The Roasting
Coffee does not taste very good immediately after the beans are done roasting. The beans emit carbon dioxide (CO2) for a period of between 12-72 hours. If you buy coffee from Weekly Roast, the beans are just about ready to use by the time the coffee reaches you. If you buy from a local roaster, find out when the coffee was roasted and make sure to wait a few days after the roasting to allow the beans to “rest” and degass before using. Coffee consumed the first 72 hours, while the beans are still degassing, can taste flat and stale. After about 72 hours is when the beans reach their peak and taste the best. As long as the coffee beans are stored correctly (see prior post on How to Store Coffee) they will be fresh for 7-10 days with a rapid decline in flavor and quality starting after around day 7.

There you have it, the coffee roasting process. Hope this answered some questions you may have had or at least opened your eyes a little on what happens ‘behind-the-scenes’ with the coffee beans before they reach your grinder, coffee machine and ultimately your cup! Ken