At Tower, we live by our motto of Flavor Above All. The key to achieving flavor perfection is not just how we source, but particularly in how we roast each of our single origin, gourmet blends, and special reserves.

Roasting coffee is both an art and a science. Done right, it transforms green coffee beans into the delicious, aromatic drink that we all know and love. 

The key to roasting is in understanding the nuances of the beans and how to bring out their best characteristics. Let’s take a closer look at all four stages of the roasting process and how they affect the final flavor and aroma of the coffee.

The First Stage is the Green Stage

At this point, the beans are still raw and unroasted, and they have a pale green color and a grassy or vegetal smell. As the beans are heated, they begin to dry out and lose their moisture. This is an important step, as the beans will not roast properly if they are too wet.

The Second Stage is the Yellowing Stage

This is when the beans start to turn a yellowish color. At this stage, the beans have lost most of their moisture, and they start to develop a slightly sweet smell. 

The yellowing stage is also the beginning of the Maillard stage — a chemical reaction that occurs between amino acids and reducing sugars when the beans are heated. It is named after French chemist Louis-Camille Maillard, who first described this reaction in 1912. 

During the Maillard stage, heat causes the amino acids in the beans to react with the reducing sugars, creating a wide variety of flavor compounds. This reaction is responsible for creating the rich, complex flavors and aromas that we associate with coffee, such as caramel, chocolate, and nuts. 

The Maillard stage is critical to the roasting process because this is when the majority of the flavors and aromas develop. Roasters pay close attention to the timing and temperature of the roast to get the best results and to bring out all the desirable flavors and aromas that the coffee beans can offer.

The First Crack Stage

The first crack marks the beginning of the caramelization of the sugars in the beans. As the beans are heated, the sugars start to break down, and the beans start to emit a popping and cracking sound, hence the name "first crack." 

At this stage, the beans have a light to medium roast and have a slightly nutty smell with a hint of sweetness. The flavors we associate with tart fruit flavors are most present in the early part of this stage and begin to diminish as the roast continues. The beans will have a light brown color, and they will be dry to the touch.

The Second Crack Stage

This stage marks the beginning of the development of darker roast flavors, such as chocolate and caramel. The beans will emit a second set of cracking sounds due to the literal cracking of the cellular structure of the beans, which releases the natural oils.

At this stage, the beans have a medium to dark roast, and they will have a rich and complex flavor with a deep, dark color. The beans will be oily to the touch, and they will have a strong, smoky aroma. The reason beans are shiny at this phase is due to the natural oils seeping through the cracks in the cell walls of the coffee and rising to the surface.

The art of roasting coffee is a process that requires a delicate balance of temperature, time, and skill. Roasting coffee is a delicate process, and beans can easily be over-roasted or under-roasted. Over-roasting can cause the beans to become bitter and burnt, while under-roasting can result in a weak, and bland flavor.

That’s why at Tower we roast in small, 20-pound batches for each of our coffees. It ensures that we can carefully monitor the temperature and time for each of our unique single origin and blends so that you always get the freshest, most flavorful cup.

Check out Tower's latest fresh-roasted coffee here.