What is a hopper bean gate or bean slide?
The base of the hopper fits into the grinder collar so that gravity will allow the beans in the hopper to fall into the grinding chute. Most espresso hoppers will have a gate or slide that closes the hopper so that no beans will flow. It is important to shut the gate before taking the hopper off of the grinder.
If you forget to close the gate when you remover the hopper, you will quite literally spill the beans. After closing each night, you should remove the hopper, store the unused beans in an airtight container, and clean the hopper with soap and water. Oil from the beans will accumulate on the walls of the hopper during the day, and your coffee shop will look dirty if you let this accumulate.