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Article:
Coffee Roasting De-mystified by: Andy White How many different names have you run across for different types of coffee roasts? Light, Medium, Dark? Espresso? Continental? Vienna, French, Italian, Spanish? City? Full-City? C'mon, who's thinking up these things? Well, the dark secret (pardon the pun) of the coffee industry is that, well, there really isn't full agreement on which roast is which. So basically, we all pretty much get to hunt around, try different coffees from different sources and pick the one(s) we like. In this article, I'll try to use the standard nomenclature, and map it to the color and texture anyone can judge for himself. The roasting adventure begins with green coffee beans. These are stored at room temperatures, at 12-15% moisture content. Roasting is done at temperatures of up to 450+ degrees F. Duration and temperature determine the roast. A coffee bean will take on heat until the internal temperature of the bean reaches approximately 212-240 deg F. At this point, the outer layer of the bean(s) will discolor, turning a nice cinnamon color. Here, steam will start being released from the bean. As the bean heats up further (approx 250-300 degrees F, again depending on the variety), the external membrane of the bean will dry up and start separating from the bean itself. At approximately 350 degrees F, the continuing heating of the bean forces a 'first crack.' This cracking occurs as moisture within is released through the existing seam in the bean. This essentially blows this small crack open, forcing the separation of the remaining bean 'chaff'. Coffee at this stage is a light brown color; entering the 'light City Roast' stage. City Roast is usually achieved at a slightly higher temperature (above 370 deg F), where the sugars within the bean start melting or '˜carmelizing'. This gives the distinctive 'coffee brown' color. City Roasts are usually stopped around 400 deg. or so. At this point, the sugars are not fully carmelized, and flavor of the beans at this stage are very much determined by their origin; not by the degree of roast. The 'Full City Roast' stage occurs at higher temperatures, just as the bean reaches the 'second crack' stage. This stage happens at different temperatures for different beans based on variety. The second crack comes as the temperatures of the bean reach the point where the cellular composition of the bean starts breaking down. To obtain the Full City roast, roasting is stopped just at the point where this second crack starts (approx 425-435 deg F.) At this point the bean is darker brown, but 'dry' looking, as the oils of the bean have not started to emerge through the molecular breakdown of the bean. Going into the second crack, we reach the 'Vienna
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