Coffee grounds are roasted coffee beans that have been ground and are ready for brewing — the state in which most coffee meets water. Grind size is the critical variable: espresso demands powder-fine particles for a 25-second extraction, while French press needs coarse chunks to survive minutes of steeping without turning bitter. Freshness fades fast once beans are ground, as volatile aromatics escape and oils oxidize, which is why serious brewers grind just before brewing. Spent grounds, meanwhile, find second lives in compost, skincare, and odour absorption.