Bottle Deposit

bottle deposit, in red wines is a lacquer-like pigmented deposit adhering to the inner bottle surface and is different from sediment. This deposition, which may begin in the first few months after bottling, may cover only a small area of the bottle shoulder or may eventually cover the entire glass surface with which the wine is in contact. Wine quality is not affected by bottle deposit and experience has shown that premium reds (particularly those made from rhône varieties) tend to exhibit this deposit more than lower-quality wines. The deposit is an insoluble complex polymer of pigmented tannins and protein.