by Larry Stang
The Roasting Process (for Good Coffee) is Easy
While Karen and I still love to meet a friend or business partner at one of our favorite local coffee hot spots, roasting my own beans puts my favorite cup of coffee right in my own kitchen. Poured every morning, several times, and even in the afternoon. I was surprised at how easy coffee roasting was with that first batch in the popcorn popper; however, under the surface, the roasting process can be as complex as you want. Here are the basics:
The Drying Phase
When the roasting begins, pale green beans heat up and moisture starts to evaporate. There is a grassy scent. The beans turn yellow and finish smelling like straw.
The Caramelization Phase
As the roasting continues, the beans darken to a milk chocolate color. They also begin to take on that characteristic coffee aroma we all know and love. This is where the flavor starts to develop. The caramelization phase ends with what is called “first crack.” First crack is when the moisture in the bean forces off the outer skin with a crack, similar to popcorn popping.
The Development Phase
The development phase begins after first crack and is the final stage of the roasting process. Most of the coffee bean’s flavor and aroma develops at this point. The color continues to darken, and “second crack” may occur. As the bean expands, it gives off gasses and the small back “cracks” with the sound of “snap-crackle-pop.” It is important to pay attention to these subtle cues as the beans begin to quickly change. You want to finish the roast when the desired roast level is achieved.
Roast level naming can vary far and wide, but I like to keep it simple and just say light, medium, and dark. The key is roasting through first crack as this removes the outer skin, known as chaff. You do this because the skin is more bitter than Uncle Henry’s ex-wife, who divorced him right before he won the lottery. Both are undrinkable.
The furthest you want to go is about the end of second crack. The color will be similar to that of an 80% dark chocolate bar. If you roast any further, you run the risk of burning the beans, also known as Italian roast.
My general rule of thumb is:
- light roast is just after first crack
- medium roast is around the beginning of second crack
- dark roast is around the end of second crack
Different flavors will be apparent in each roast. A light roast will highlight floral and fruity notes while a darker roast will present warmer flavors and aromas like nuts and chocolate.
The roasting process becomes more complex when you factor in the many variables. First, beans can vary significantly by region, altitude grown in, and processing method. Some beans are better for different roast profiles. Then, roasting time, temperature and quantity will change the flavor considerably. Moving too fast through caramelization will influence sweetness; yet, roasting too long or hot, you “bake” off much of the flavor. Each roast will have its quirks, too, as ambient temperature and humidity can significantly affect the roast profile.