The second phase of the roast is called the Maillard phase. It is a reference to Maillard reactions that are all around us. Whenever you roast a chicken or make toasts, baking cookies you’re using maillard reactions to develop new flavors.
Maillard reactions are a series of chemical reactions between reducing sugars and amino acids to create melanoidins. Melanoidins are compounds responsible for the brown color of foods and unique flavor. These reactions occur rapidly between 140 – 165 Celsius degrees. In coffee roasting, the maillard phase starts around 150 celsius degrees when coffee turns fully yellow and ends around 190 celsius degrees with the first crack.
Length of maillard phase is linked with body viscosity of the coffee. Many coffee authors make this assumption. The longer the Maillard phase is the higher and more viscous the body is. This allows the roaster to manipulate one of the important attributes of coffee.
A typical maillard phase lasts 3-5 minutes depending on your roaster, profile etc. While using a longer maillard phase increases body perception, you need to be careful when stretching it to extreme times. Losing too much of the heat and momentum of bean development may result in overly long roast and underdevelopment defects. Some coffees can benefit from long maillard phases and some can benefit from short ones. It’s not always like “the longer, the better”.
I hope this helps you with developing your roast profile. If you have any questions feel free to ask us.
Our step-by-step roasting guide has been design for you by Aleksander Smet, 2022 Polish Roasting and Cup Tasters Champion.
