What are 'broken beans' in coffee grading?

In the meticulous world of coffee grading, every bean is expected to be whole and uniform. Broken beans—fragments, chips, or split seeds—are a common physical defect that graders look for during the inspection process. These are typically classified as secondary defects because, while they don't always ruin a cup as severely as a 'sour' or 'black' bean, they represent a failure in the processing or handling chain.

Broken beans usually occur during the milling process, specifically during hulling, where the protective parchment layer is removed from the green bean. If the machinery is not calibrated correctly or if the beans are too dry and brittle, the huller can easily crack or shatter them. They can also occur during transport or rough handling. Because these fragments have a different surface area and density than whole beans, they react to heat differently in the roaster. A broken bean will often roast much faster than a whole one, leading to burnt or bitter notes that can taint the entire batch.

Sorting criteria for specialty coffee are designed to minimize these fragments. Through the use of screen sorting and gravity tables, processors work to remove broken beans and other debris to ensure the final lot is as uniform as possible. This uniformity is key to a successful roast. When a roaster has a batch of beans that are all roughly the same size and shape, they can apply heat evenly, resulting in a balanced and clean-tasting cup.

For the reader, the presence of broken beans is a sign of less-than-ideal processing. While you might occasionally find a small fragment in a bag of coffee, a high-quality specialty lot should be largely free of them. This is why grading is so important; it is the process of refining the harvest to ensure that only the best, most intact beans make it to your cup. By removing these defects, the industry ensures that the coffee you brew is as consistent and delicious as the farmer intended.