The Keurig single-cup brewing system uses a special packaging for coffee, tea and hot cocoa called K-Cup portion packs or "K-Cups". Each K-Cup is an airtight, mini-brewer that locks out oxygen, light, moisture and humidity while locking in freshness and flavor. Simply insert the no mess K-Cup into the brewer and hit the brew button for a fresh-brewed, perfect cup of coffee or tea in under a minute.