Secrets of Coffee Roasting, De-Mystified

I started my coffee roasting career as a home roaster. Getting started was easier than I thought. And as I did so, it occured to me how a relatively simple concept, roasting coffee beans, has been made to appear to be an arcane art, with a variety of roast types held out as arcane knowledge. 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 a process of observing 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