ABSTRACT
The precipitation of materials in wine a well as color, aroma and taste changes which occur can either be desirable or undesirable. The stability problems that face the winemaker are: oxidation, tartrate, color, hydrogen sulfide (H2S), protein, metal, phenols, and microbiological. This chapter lists the materials which cause the most instability and cloudiness in wines. The main stability problem with color in white wines is directly attributable to oxidation problems. The removal of H2S from wines can be managed by addition of copper sulfate. There are several ways to remove natural protein from a wine. One is to flash pasteurize the wine to 160°F (71°C), then chill and filter it. There are three common metals (copper, iron, aluminum) which can cause problems with wines. Phenolic material in white wines occasionally will cause some problems when other constituents and conditions are correct.
