The above illustration is a good visual for understanding the different levels of roasted coffee. Keep in mind that this is a simplified guide, as there are many sub-categories of these roast levels, but this is a good starting point for understanding the general differences between the roast levels of coffee.
Light roasts are typically used to highlight inherent flavors in any given coffee bean. As green coffee beans are roasted, their cellular structures begin to breakdown and change. So, the longer you roast a coffee bean, the more it changes the flavor that was developed during its growth as a fruit. Keep in mind that these flavors we are referring to are typically subtle notes of fruit, sugars, chocolates, earthiness, and acidity.
Light roasts also contain higher levels of acidity, or sourness, than darker roasts do. This is a result of less roasting time as well, as certain acids within the bean begin to breakdown and cook-off the longer it is roasted. This acidity is not the same as say, a sour piece of candy, but rather refers to a flavor note in coffee. This acidity is often a desired flavor note that adds to the complexity of the finished product, but at the end of the day, is primarily a preference.
Expect a light roasted coffee to be bright, juicy, slightly sour, and full of fruity flavors.
Medium roasts are the most popular roast level of coffee in the United States. Roasted a bit longer than light roasts, some acids and flavors begin to cook out and sugars begin to caramelize, typically resulting in a sweeter cup. Stopping the roast at this level preserves some of the flavors and compounds from the green bean while new flavors are introduced from the chemical changes that the heat creates, resulting in a very balanced cup.
Depending on the origin of the coffee, you may still find some acidity in a medium roast. The acidity notes are typically more muted than a light roast would be, which is why medium roasts will be more of a crowd-pleaser than a light roast.
Overall, expect a very balanced and sweet base flavor with medium body.
Medium/Dark roasts offer a great balance of bitter and sweet flavors, and the beans will be a dark brown with small amounts of oil on the surface. At this roasting point, sugars have almost been fully caramelized, resulting in a bittersweet taste that most people enjoy. Not overpowering, the bittersweet is usually complemented by a strong aroma, chocolatey flavors, and possibly even some left over acidity that adds a bit of an aftertaste.
Medium/Dark roasts will often times also have a heavier body than its lighter counterparts. Body can be described as the “mouthfeel” of the coffee. This is sometimes a thick or a silky feeling that adds to the flavors of the coffee.
Expect a Medium/Dark roast to be very fragrant, have some slightly bittersweet qualities, and a thicker mouthfeel.
Ah Dark Roasts, the favorite of the all day coffee drinkers. Dark Roasts are significantly more bitter than lighter roasts, as the sugars have fully caramelized and begin to blacken, and the aroma is very strong. Cell structures in the bean have almost completely broken down and oils have completely moved to the surface of the bean. Bean color will be very dark brown to black, with a sheen of oil on the surface. A significant amount of the beans original flavor has been roasted off.
People often associate the bitter, smokey flavors of a dark roast to have more caffeine than lighter roasts. Interestingly enough, dark roasts technically contain less coffee than lighter roasts as some of the caffeine cooks out the longer it is roasted. That’s not to say that dark roasts can’t have more caffeine than light roasts, as caffeine content largely depends on bean type, but if you were to roast the same coffee light & dark, the dark would technically contain less caffeiene.
Expect a Dark Roast to be smokey & bittersweet, often times with a dark chocolate note and a silky mouthfeel.
Overall, roast level is purely preference. Medium & Dark roasts have been very popular over the last 30 years due to the consistency of flavor that they can create and the bittersweet qualities they produce. As coffee has become more craft over the past decade, similar to the craft beer surge we have seen, people have been exploring with lighter roasts to emphasize the more natural and fruity flavors of the coffee bean. Whatever your taste, we hope this guide has been helpful in understanding the spectrum of roasts that coffee can be found in.