Roasting usually consists of three stages: drying, yellowing/browning, and caramelisation/acid development. You could be excused for thinking that the coffee beans are dry when they’re shipped, but they’re actually only dry on the outside. Inside there’s still fluid. So they go into the roaster to dry them out completely. It’s during this stage that the sugar starts fermenting and the water inside turns to gas.
So imagine the coffee beans expanding as the gas grows. They turn yellow and then to brown, with various shades of both in between. And when they can’t take it anymore, they crack, sounding a lot like popcorn popping. One crack. This is where it gets serious. The sugars and the acids fight for space. Too much sugar and you get a burnt flavour; too many acids and the coffee will taste bitter. Getting it just right is the job of the Coffee Roaster. If the second crack comes, the beans are beyond redemption.
There’s a lot of experimentation involved. A lot of watching and waiting to take good advantage of that short window between the first and the second crack, the crack you don’t want to hear.
So why are roast profiles important? What do you need to decide, if anything, before you start? Well, it helps to know what you’re going to use your coffee for. Will it be a filter coffee or are you going to use it in, say, the Tecnora Classico 107M Espresso Coffee Maker and the Cremiere TCM 106A espresso coffee machines? This will determine how light or dark the beans should be and how long the roast should take.