when coffee is roasting, it expands, pops, and little pieces of chaff break away from the bean. it smells somewhat like hay, is feather-light, extremely flammable. if you brew it with the coffee, it tastes very bitter, so you have to separate it from the roasted beans. the bible talks about tossing grain up into the wind so the chaff blows away while the kernels fall back to the ground. this is the basic idea. if you are roasting at home, you can sift the chaff out using a colander or stir the coffee in front of a fan on low speed. commercial roasters have an exhaust fan that carries the chaff over to a collection tank away from the heat.
but are there uses for this organic matter? in soil, the chaff is fantastic at absorbing and retaining moisture, so stirring in coffee chaff in small amounts can be a helpful addition. it also works as chicken bedding! or one can spread it on a muddy path in the spring to help dry the mud. or use it like sawdust in the bottom of compostable toilets. but the latest use for this substance will raise some eyebrows…
a farmer stopped in recently and submitted a sample for nutritional food analysis, and it came back showing to be full of protein, particularly well paired for the digestive system of cattle. the report looks like this:
protein 16.7%, digestible protein 12%, acid detergent fiber 49% neutral detergent fiber 63% estimated net energy 87% calcium 1% phosphorus .07% potassium 1% magnesium .2% sulfur .2%
so he carried away about 50 pounds and is going to try adding it to food for his herd of heifers. my hunch is that there is caffeine in the chaff, and he will have some very happy cows. we will have to wait and see.