The Nespresso one cup brewing system uses propriety Nespresso capsules developed by Nestlé. The color-coded aluminum capsules are filled with the appropriate amount of ground coffee and then hermetically-sealed to prevent oxidation. Once in the Nespresso machine, a blade system perforates the seal and pressurized, hot water is used to brew the espresso. Since the Nespresso capsules are made out of aluminum, they can be recycled.
The Nespresso Gemini brewers — those in offices — use Nespresso capsules that are designed differently and manufactured using a combination of aluminum and plastic. Because plastic is incorporated into the manufacturing process, these capsules cannot be recycled.