It's also good material for composting and vermicomposting. Relatively regular grain size probably makes it a decent source for home biochar (definitely better

It's also good material for composting and vermicomposting. Relatively regular grain size probably makes it a decent source for home biochar (definitely better than wood if you're just looking to add high-surface-area microbe housing to your soil). Given that coffee is so popular around the world, I think there could be real benefits to using it as a building material if it can lessen the need for new concrete.