Chaff: What Is It?

Have you ever opened a bag of freshly roasted coffee and saw small flakey pieces of, well, chaff? It looks like tiny pencil shavings, and although it's completely normal, it may be surprising to see if you're not aware of what it is.

"Silverskin" is a husk that grows over coffee seeds. After the coffee cherries are picked, the amount of silverskin left on the seed changes based on the processing method, i.e., washed, honey, dry. Additionally, the origin and varietal of the coffee change the amount naturally grown on the seed. As green coffee beans roast, the silverskin begins to wear away and collect in a bin attached to the roaster's exhaust. This byproduct is known as "chaff." Although most chaff is discarded during the roasting process, some remains in the bean and later is found after being ground. Generally, lightly roasted coffee will reveal more chaff, while darker roasted coffee will reveal less. That is due to the temperature differences and expansion rate involved with roasting. 

Fortunately for us, chaff has no effect on the flavor profile of a coffee, so whether you see a lot or none at all, your coffee will be just as delicious regardless.

Coffee Cherry DiagramChaff