Get Started Roasting Coffee
Now that you have a roasting machine and green coffee, it’s time to begin roasting.
It’s important to understand something about what is happening to the coffee in the roasting process. What follows is an informative discussion of the physical and chemical changes that happen throughout the roast.
The question is, how does the coffee go from the green seed that is dense, heavy and contains a great deal of moisture to the lighter (in weight), larger (in volume), dark roasted coffee that is so rich with flavor and complexity. As the coffee is rapidly heated it dries up, its chemistry is transformed, its sugars caramelize and its cell structure breaks down. In the process, the properties inherent in the coffee are transformed by the roast and that’s where the complexity of coffee flavor comes from: the origin flavors in relation to the “roast” flavors. The art of roasting is in trying to find the balance that best honors the origin flavor while roasting long enough to develop those flavors in interesting ways. On one end of the spectrum, unroasted coffee has a sour smell, and a cereal or grain like flavor (try chewing on a green coffee seed- it’s very hard). At the other end, as the roast gets in to dark territory, the origin flavors are eclipsed and eventually obliterated by the roast, especially when the coffee reaches a roast level of Full City + and beyond.
Changes to the Coffee During the Roast
Here is a summary of what happens in the roast (notice that the senses are engaged in determining the roast level):
1. The first part of the roast consists of drying out the seed. This takes the most time. The further you go into the roast, the faster it progresses (it’s important to keep that in mind).
2. After the initial drying of the green coffee, the beans begin to turn yellow and then brown as the sugars in the coffee caramelize.
3. This is when we enter into the phase of the roast that we call “first crack”, which is the loud cracking noise that the coffee makes as the cell structure begins to break down. Once first crack finishes, the coffee has been roasted to a drinkable state. You can stop the roast at any point after first crack finishes. This light level of roast is called a City Roast.
4. After first crack, there is a period before the coffee enters “second crack” (the amount of time varies greatly depending on the coffee’s properties and roasting methods). In this period the coffee gets progressively darker from City to City + (medium) to City ++ to Full City which is just before second crack begins.
5. Second crack is a quick snapping sound and as it begins the amount of smoke produced by the roast increases. At this point the roast is a Full City +.
When you reach the desired roast stage it is important to stop the roast and cool the beans as quickly as possible (a metal colander works great for this). The beans will continue to roast when removed from the heat until they are cooled. Once they reach room temperature the coffee can be stored (canning jars with a loosely tightened lid work great as they beans de-gas). Allow the coffee to rest overnight (at least) before grinding and brewing.
The following video is of the actual roasting process in a popcorn popper.
Tip for roasting:
We recommend roasting to a light or medium roast in order to experience the coffee origin flavors rather than having them fully eclipsed by the roast. Then, you can experiment with progressively darker roasts to see how the roast develops the origin flavors and at what roast stage they are in balance (of course, this is a matter of preference).
The following video shows the coffee at the various stages throughout the roast, from the green coffee to a Full City + roast.
Music by AfroCubism, The Black Keys and KRS-One.