Capsule: This plate balances the forces and prevents the cork from getting caught in the hemp threads used until then under pressure, which could cause gas or liquid to escape.
Adolphe was concerned about the high losses due to various causes: transport, weather, and temperature fluctuations caused a lot of damage: bottles broke or corks popped. He also had the idea of replacing the hemp cords with iron wire, which was called a "muselet" (wire cage).
The combination of metal capsule and wire cage for sealing champagne bottles is still used today and has been optimized over time. This technical and qualitative revolution has even become an investment. To the great delight of placomusophiles, collectors in search of capsules, which are sometimes traded at gold prices.
Source: La Champagne Viticole