Roasting Green Coffee Beans for the Perfect Cup

Did you know your favorite cup of java starts as a bean with a green shade (also known as green coffee)? Coffee is green because it is the seed of a fruit. Roasting is essentially the process of roasting a green coffee bean until it turns brown. Green coffee beans are matured through the roasting process. A green coffee bean has sugars and acids that are created into a flavorful java experience through the roasting process. Roasting green coffee beans happens in three stages: drying, browning and acidifying.

Step 1

Green coffee beans are put into a heated roasting drum. At this point, the inside of a green coffee bean is filled with water. The green bean is dried as the heat from the roaster begins to dry and enhance the natural sugars inside the green coffee bean. Step one is about developing the sugar within the green coffee bean. As the green coffee bean continues to warm up, the water inside the coffee bean turns into a gas.

Step 2

In this stage, all the water inside the green coffee bean has turned into gas, and the green coffee beans begin to turn yellow and then brown. The coffee bean becomes larger in size because the gas inside the green bean builds up pressure on the wall of the coffee bean.

Step 3

The water inside the green coffee bean has turned into vapor, and as that vapor escapes from the coffee bean, it makes a popping or cracking sound. When this happens, the sugars and acids begin to intermingle, and the sugar enhancement that started in step one has reached full caramelization. The acid that is endemic in green coffee beans begins to develop.

There is a delicate balance in this step in the green bean roasting process. If the sugars become too caramelized, then the coffee will have a burned taste. If the roasting process allows too much acidity to develop, then the coffee will have a sour or pungent flavor.

The goal is to have a perfectly balanced flavor profile that rests between acidity and sugar. The roasting process is designed to bring out the best qualities of each green coffee bean. The ideal balance of sugar and acidity will give you a bright, clean flavor that brings you back to enjoy another cup of coffee. When this balance is achieved, the roasting is complete.

Flavor Profiles of Green Coffee Beans

Green coffee beans have a unique flavor profile and distinct characteristics depending on where the coffee bean was grown. Another difference is dry processing vs. wet processing of green coffee beans. Click here for a coffee glossary. Finally, consider the various roasting profiles, from light roast to dark roast which have significant effects on the flavor. To learn more about the flavor profiles of each coffee region, complete this form and download the report.

Bulk Green Coffee Beans

When you purchase bulk green coffee beans, the supplier will provide a recommended roasting technique for each type of green bean. Click here for an example of how to roast bulk green coffee beans. How you roast green coffee will completely change the taste of the coffee being produced.

Roasting Degree of Green Coffee Beans

The roasting degree is measured by a color meter or by a taster. A green coffee bean roaster must decide upon the roast degree. A light roasted coffee bean is more acidic and fruity, and a dark roasted coffee bean is more bitter and burnt. In general, a light roasted coffee brings out the original character of the raw green coffee bean better than a dark roasted coffee.   

Roasting Time for Green Coffee Beans

The total roasting time for green coffee beans is important. Fast roasting provides more aroma compounds, makes the total flavor more robust, and enhances the full flavors of the coffee bean. Slow roasting allows the organic acids to have more time to break down, which makes the coffee less acidic. If you want a low acidity coffee, especially with espresso blends, then slow roasting is the way to go.

When you buy bulk green coffee beans, the magic formula for perfectly roasted coffee starts with excellent quality green coffee beans plus the right amount of heat and the right amount of time. Happy roasting!