What is the exact composition of these paper-based capsules and why are they not made of 100% paper?

The capsules consist of 82% paper pulp¹ and a thin, biodegradable coating as an oxygen barrier.  To protect the coffee from oxidation and preserve the delicate aromas, taste and freshness, the capsule is lined with a thin, biodegradable film that ensures a high-quality result in the cup. 

_{¹ Our paper-based capsules are certified home compostable and contain 82% paper. DISPOSAL: Dispose of the capsule after use in home compost if available. If you do not have a home compost, take the capsules to a Nespresso collection point. If this is also not possible, dispose of the capsules in the residual waste. Do not dispose of them in the paper or organic waste garbage can. Dispose of the bag in the yellow garbage can or yellow bag.}

_{For more information about the capsule and composting, visit our website: Heimkompostierbare Nespresso Kapseln | Nespresso Österreich}