How to Roast Coffee At Home

Posted by john cozzarelli on

Roasting coffee can often seem like a complicated task, you'll often find a lot of pretentiousness behind the theory, and I'm sure most people aren't even aware of the process. This shouldn't be further from the truth, Roasting coffee is a practice that's been in place since the 15th century. In it's simplest form it is the application of heat to raw aka green coffee beans until the sugar breaks down, caramelizies, and browns the beans.

This video is a really abridged version explaining the three phases of roasting, each roaster is different, and you method of convection will ultimately determine your times, temperatures, and phase switches so this is all simply a jumping point to get you going!

Phase One; Drying- The goal of the drying phase is to remove as much moisture content you can from the bean without scorching it. This should last 40-55% percent of your overall roast time. You will notice the beans go from their raw hardened green state to a yellow to yellowish brown with scents of hay.

Phase Two; Roasting- This begins when the Mailiard reaction occurs, which can happen anywhere between 270-320 degrees. The Mailiard reaction is a chemical reaction that occurs when there is a heat application to something. You see it in searing steaks, caramelizing onions, and toasting marshmallows. This phase should last about 20-30 percent of the roast.

Phase Three; Development- This begins when the beans enter "first crack" first crack is essentially when the coffee has taken in so much heat that it begins to release it back out going from an endothermic heat transfer to an exothermic one. The beans are so hot at this point that you should kill your heat and let the residual heat they are releasing finish up the roast. This phase is known as the development phase because, it is really where the make or break for your flavor profile happens, that is why it is called the development phase. This should be somewhere between 20-25% of your overall roast, if it is lower you will find yourself with a brighter coffee where as if it is longer you might find a bolder smokier flavor. However there are always outliers to these rules, every bean has it's own characteristics.

Remember flavor is subjective and if you do something that you think taste good, and you had fun doing it. Then you won! Just have fun with it.