Why does Nespresso use aluminum for its capsules?

Among all materials that we have examined, aluminium has been singled out as best in terms of protecting the freshness and aromas of our coffees, all the while interacting with our machines in such a way as to consistently produce the high quality-coffee that our consumers have come to expect. On top of that, aluminium also has the unique advantage of being infinitely recyclable.
The use of aluminium eliminates the need for any additional packaging or overwrap to protect the freshness of coffee, combined with its light-weighted nature, are environmental advantages from both the logistics perspective and sustainability perspective.
Aluminium ensures optimal protection from air and light to conserve freshness over time. Nespresso aluminium capsules are coated with a food-grade lacquer to prevent any contact between the aluminium and the ground coffee.
Aluminium is also a material that can be infinitely recycled without losing any of its properties (approximately one-third of the global demand for the material. By the end of 2022, up to 80-85% of Nespresso's Original and Vertuo coffee capsules will be made from recycled aluminum).
Coffee grounds can also be recycled in various ways, such as being used as natural agricultural fertilizer or as a source of energy for power or heating systems. In Hong Kong, the used coffee grounds are composted and used as fertilizer in some local farm.