One of the things that confused me the most when getting into the world of coffee was roast levels. Specifically, how light or dark has a coffee been roasted. Every coffee company seems to have their own standard and none of them seem to match. Usually the same terms are used to describe the roast level: light, medium, dark, and combinations of the three, but rarely are they applied in the same way.
For example, on the left is a coffee that Starbucks says is a medium roast. On the right is a coffee that I would say is my medium roast. The only way these two can both be called medium is if we completely ignore any objective standard.
So if there can be no agreed upon standard for what constitutes a light, medium, dark, etc. roast, then what's the solution? Fortunately, there is a much more agreed upon standard that is used by roasters the world over. And while some of the language gets interchanged here and there, it's a much more consistent way of describing where the coffee was in the roasting process when its particular roasting journey came to an end.
And now we reach the real question, "why doesn't everyone use this standard?" Because to use this standard, you have to know a bit about the roasting process itself and apparently most roasters think their average customer isn't capable or isn't interested in understanding how their coffee is roasted. Fortunately for you, we don't think that at all.
The Roasting Process
So let's take a top-level look at the roasting process as a whole. To start, the coffee gets dropped into a very hot roaster. It goes through several processes that dry off most of the moisture and then change the color of the bean from green to yellow. Then the coffee starts to brown as the heat begins acting on the proteins in the bean through a process you may have heard of called the Maillard reaction. It's the same reason your steak gets that delicious, seared, crunchy outside when you grill it on high heat, but we digress.
At this point in the roast, hopefully between 8 and 11 minutes in, the coffee starts to pop like popcorn. This is what roasters call first crack and it's caused by the internal moisture content of the bean turning from water to steam. The steam cracks the physical structure of the bean as it searches for a way out. This is where we start naming roast levels. If we drop the coffee out of the roaster as the coffee is finishing first crack, it's called a city roast.
If we continue the roast beyond first crack for anywhere from 15 to 30 seconds, we move from a city roast to a city plus (city +) roast.
As we continue roasting, we move towards a second round of cracking that sounds more like putting milk into rice crispies. If we stop the roast just before this second crack, it's a full city roast. And if we wait until we hear the first few cracks of second crack, it's a full city plus roast.
If you're taking notes at home, this is about as dark as we roast coffee for two really good reasons. First, if the roast continues beyond this point, we lose all of the flavor characteristics that made the coffee unique. If you roast a Kenyan, a Guatemalan, a Colombian, and a Rwandan and you roast darker than full city plus, all of the coffees will pretty much taste the same in the cup. The flavor of the roast eclipses the flavor of the coffee.
Second, in our opinion, this is when coffee begins to develop a burnt, bitter flavor. Throughout the roasting process, we're burning and caramelizing the sugar that is naturally found in the coffee. Once you go too far, most of the natural sugars are gone and the coffee begins to burn.
If we continue on and let the roast go until second crack is really developed we're now into the realm of a Vienna roast. Once we approach the end of second crack, it's a French roast. The sugars have all caramelized and the bean is black and burnt. Really black and really burnt. If the roast continues for another 30 seconds to a minute, the coffee becomes like charcoal. You could write your name with it. And there's a decent chance that once it drops out of the roaster, the sudden exposure to air will cause it to burst into flame. So there's that.
Some people think that a darker roast means a stronger cup of coffee. But the reality is that how strong or weak the coffee is depends on the ratio of coffee to water and how the coffee is brewed. Once coffee gets to french roast levels, the solubility of the coffee begins to decrease. Also, caffeine content decreases as the coffee is roasted. So a vienna or french roast has substantially less caffeine than a city roast.
So to recap: first crack, city roast, city plus roast, full city roast, second crack, full city plus roast, viennese roast, french roast, fire. That's why we choose to roast on the lighter end of the spectrum, so that you can actually taste the goodness of the coffee itself. Obviously there are a lot of people who like burnt coffee - after all Starbucks is worth almost $90 billion. But for us, it's more important to taste all of the flavors that make coffee so delicious.