The Effect of Roast Profile on Body



One of my friends always likes to talk about the body or mouthfeel of a coffee. In his mind, it is something that customers can easily identify, and I’m inclined to agree. We in the specialty industry tend to lead customers straight to the deep end when we taste or cup with them. We will discuss the nuances between citrus fruits, identify a particular species of flower, or go for the novel and shocking descriptor. Really, most of it just goes way over their heads. But, with a little coaxing or some examples, most people can get in on the discussion of body.

Body is the weight, texture, and mouthfeel of the coffee. It shows up on the SCAA cupping form as a characteristic of green coffee, is altered in the process of brewing, and is often linked in casual conversation with processing method. Something that we as roasters need to consider, however, is that the body of the coffee is greatly affected by the way we roast.

Since you, the roaster, have control over the expression of the body, and you have a protocol that gives you a large window of roast length and no defined profile, you must be vigilant to always record your roast data in order to be fair to the coffee.

What I want to posit to you is a concept taken from my new roasting handbook, Modulating the Flavor Profile of Coffee: One Roaster’s Manifesto. The concept is that the formation of body is necessarily linked to the Maillard reaction during a roast. Specifically, it is linked to the formation of melanoidins. Melanoidins are brown, high molecular weight polymers formed during the Maillard reaction. In their book Espresso: The Science of Quality, Andrea Illy and Rinantonio Viani cite research linking melanoidins with texture. Interestingly enough, there is also linkage between molecular weight and viscosity. Essentially, higher molecular weight yields greater viscosity. Therefore, it would stand to reason that more melanoidins created by the Maillard reaction would yield higher overall molecular weight, which would lead to a greater viscosity and a sense of weight or thickness when relating to mouthfeel.

The awesome thing about this information is that we can (to a degree) control how the Maillard reaction occurs in our roasters through the adjustment of our profiles. The Maillard reaction begins around the same time you notice the beans change from green (pale green) to yellow in your roaster. These reactions will continue until either the bean runs out of reactants or you cool the beans by dropping the coffee into the cooling tray or starting the cooling cycle, (It may continue a little after depending on how efficient your cooling apparatus is.)

What I have noticed in my experimentation and blind cuppings is that the longer the Maillard reaction is allowed to continue, the greater the experience of the intensity of body (texture, viscosity, thickness). On the other hand, the shorter the time allowed for the Maillard reaction, the weaker the intensity of body.

There is, of course, a lot more involved in how this process occurs, and the way in which we can control it, which I delve into in the book, but I want to discuss how this may be applied.

First, it is awesome that we have control like this. Knowing this way to approach coffee roasting and profile development means that you are not caught in one particular expression of body. You can take the coffee and work it so you develop the body you want. It is crucial to note that each coffee has a range in which it can exist and within which you can modulate its attributes, so sourcing is super critical as well—but the bottom line is you have the control.

Second, it is a weighty responsibility to be aware of it. Body is a scoring section on the SCAA, Q, and Cup of Excellence score sheets. These sheets classify the overall quality of the green coffee, and influence buying and pricing decisions. Since you, the roaster, have control over the expression of the body, and you have a protocol that gives you a large window of roast length and no defined profile, you must be vigilant to always record your roast data in order to be fair to the coffee.

A method we use that works well is this: while sample roasting I record the time of the beginning of color change and note the duration to the end of the roast. That way I can be informed about the roast’s influence on body after I have cupped blindly and can make adjustments to the way I am judging it, or even decide that a re-roast is necessary.

Take control of your roast. Using the length of the Maillard reaction to control how the intensity of the body presents in the cup is just one of the many ways you can control your coffees. We must strive to be educated, intentional, and meticulous, even with regard to the nuances, because everything we do will affect the final flavor and quality of the cup.

Rob Hoos is the Nossa Familia Coffee’s head roaster and consults through his company, Rob Hoos Coffee Consulting.