Delve very deep into coffee and coffee roasting and you will undoubtedly be inundated with cryptic roast degree terms and systems. Full city, light, city, French, dark, Italian, American, cinnamon, Spanish, espresso, Viennese, etc. You may ask “Well Alex, how do all these compare to each other?”, a very good question, to wit I would respond “It depends whom you ask”. Yes, unfortunately there is really no set standardization in these terms. The terms do have a generally accepted range of a degree that they refer to, but when you get down to specifics, they lose their reliability. The terms have no set roasted degree, even the order of roast degree the terms refer to are not kept consistant. Some roasters will have an espresso roast lighter than their French roast, some will be the reverse, Viennese seems to float around, cinnamon and light are often switched, etc. This peeves me. So I try to stick with the following system: Light, medium, and dark. There is no question of which terms refer to roasts longer or shorter than the others, and the specifics are not lost. because the three terms can be further broken down into: very light, light-medium, medium-light, medium, medium-dark, dark-medium, dark, and very dark, and described as follows:
Light - Light brown to cinnamon color Low body and light acidity. The beans are dry. This roast is too light and does not allow the coffee to develop to its full potential.
Medium - Light Medium light brown color. The acidity brightens and body increases slightly. The bean is still dry.
Medium - Medium brown color. The acidity continues to increase and the body becomes more potent. The bean is mostly dry.
Medium - Dark Rich brown color. Very small droplets of oil appear on surface. The acidity is slowly diminished and body is most potent. This is the ideal roast for a well blended espresso.
Dark - Deep brownish/black color. The bean has spots of oil or is completely oily. Subtle nuances are diminished. Flavor decreases, while body dominates.
Very Dark - Black surface covered with oil. All subtle nuances are gone, aroma is minor, and body is thin. This roast is characteristic of American espresso.
To be quantitative and scientific about the roast degree, one can use a machine (called an Agtron) to measure the roast degree of the coffee. The machine produces a number representing the roast degree, thus we can really standardize by saying something like Agtron #60-50 is medium-light roast. What a wonderful world that would be.
Many of you may know that we roast some of our own coffee in the shop, but believe it or not, its really not very difficult or expensive to start roasting coffee yourself at home! All you really need is an air popcorn popper and some green beans. Popcorn poppers make great roasters if you only need to roast very small batches. The hot air whirlwind produced by poppers keep the roast even and swift. Firstly, find a spot you don't mind getting a little messy, and has very good ventilation ie. outside or under a kitchen hood. To start, turn on the popper, and add green beans into the cylindrical chamber (We have some green beans you can buy from us, and soon we'll have several hundred pounds more and a greater selection.). Be careful not to add to many beans or the cyclone will slow, resulting in a more uneven roast. Within minutes you will see the beans begin to turn tan and brown. While beans roast, they shed their thin outer covering, this is referred to as chaff. Conveniently, because the chaff is so light, the air popper separates it from the beans as it flies out the top of the popper (this is the messy part). As you wait, you should hear the beans undergo one or two "cracks". Like popcorn, all the beans don't make the cracking sounds at the same time. However, their are definite sets of cracks corresponding to roast degrees. You will want to stop roasting your coffee somewhere between the beginning of the first crack and a little after the second crack (depending on what roast degree you prefer) . If you hit the third crack I recommend tossing the beans and trying again; as the brew will be very carbony; like brewed ashes.
When you stop the machine, immediately pour the beans into a metal container in which you can shake and toss the beans to cool them. Be very careful at this stage because the beans will be extremely hot. After the beans are cool, you may brew and/or store them. Some air popcorn poppers are more suited to coffee roasting than others. You may run into a popper that has to short of a roasting chamber to work. As the beans roast, they loose a significant amount of their weight (primarily water). So the heavier unroasted beans swirl at the bottom of the chamber while dark roasting beans swirl much higher. Some poppers are to short to accommodate darker roasts. Thus at a certain roast degree, the beans are flung out of the chamber like the chaff was. Sometimes that can be convenient, usually it is not. So with very little investment you can actually roast your own coffee! Getting an incredibly fresh cup while growing in appreciation of the art and science of roasting. As a sidenote, there are also products built for home roasting, but most are little more than an popcorn popper slightly altered for roasting with a much bigger price tag. Happy roasting.
Yes and no. Coffee can have a good amount of caramel-like aromas that cause it to taste like coffee with a hint of caramel who's sweetness is masked by coffee's natural bitterness; but you will not mistake you coffee for liquid caramel. Roasting coffee causes the sugars in the coffee to first caramelize (turn to caramel) then carbonize (turn to ash) the same way as would putting a blowtorch to granulated sugar. The more carbony the coffee is, the more of the natural coffee sugars and aromas are burned off in lieu of the carbony bite. Different people prefer different ratios of the caramel-coffee taste to the carbony taste. In lighter roasts there are also enzymatic (herby, flowery, fruity) aromas. The enzymatic aromas then give way to the sugar browning (caramelization) aromas, which then fade into the carbonization aromas the darker the coffee is roasted.
Unless a coffee is named after its growing region it is most likely a blend of beans from different regions. Probably the most known blend (and the oldest) is a simple Mocha-Java. The blend originated when the only two coffees were Yemen Mocha, and Java, yet the blend retains its popularity because it embodies the principle of balancing extremes. Together, the fruity and winey Yemen, with the rounder, deep-toned Java make a balanced and complete cup. To create a quality blend, you need an idea of your goal cup, and a substantial amount of expertise. The blender must have an extensive knowledge of the flavors profiles of different regions and how different processes effect those flavors. As many blends are of beans at different roast degrees (to maximize roast taste complexity) a roaster must also know how those flavor profiles change through the roast. They must also continuously sample beans from their supplying farms to evaluate the change and adjust their blends accordingly. Blends generally contain up to nine different regions (after nine it gets pretty muddy and pointless) and the beans can be blended before roasting or after. Blending is a crucial step in getting that cup of coffee that we're looking for, and a rather complex and involved step as well.
The roast degree (how light or dark the coffee is roasted) has the most profound effect on the coffees taste. It is the easiest identifiable coffee characteristic. The second most obvious characteristic I would say would be whether the coffee was dry-processed or wet-processed, but the way the coffee is processed and the degree it is roasted to often go hand-in -hand (most wet-processed coffees are roasted lighter, while dry-processed coffees are roasted darker). A roaster selects a certain roast degree for a coffee to bring out the specific coffee's inherent talent. If a coffee from a specific estate has the ability to have a wonderful acidity and great enzymatic flavors, the roaster would be foolish to roast this coffee dark, because then much of the acidity and enzymatic flavors would be roasted out. As a coffee is roasted
1. acidity peaks very early and decreases throughout the roast
2. body peaks at a medium-dark roast and tapers back down
3. different natural aromas inherent in the beans are emphasized -- in light roasts the enzymatic aromas (flowery, fruity, herby), in medium roasts the sugar browning aromas (nutty, caramelly, chocolaty), and in darker roasts the dry distillation aromas (resinous, spicy, carbony), and
4. past a medium roast, natural coffee sugars and aromas are roasted out in lieu of carbon (ash).
Coffee beans that are wet-processed (as are most central and south Americans, and Africans) lend themselves better to lighter roasts because wet-processing engenders a cleaner and brighter acidity; while dry-processed beans (most Indonesians) lend themselves better to darker roasts because the processing engenders more rich earthy dark tones without acidity. This all emphasizes that most of what one tastes in a cup of coffee are the processes the coffee went through and not specifically its origin; though coffee from a specific origin generally undergoes the same processes all coffee from that origin has for years.