Diagnostic Key Postfermentation Types of Spoilage

Post Fermentation Off-Character Formation

Types of Spoilage

The above discussion covers off characters that can be produced by Saccharomyces cerevisiae.  Off aromas in wines can also be produced by other microbes, most notably Brettanomyces bruxellensis and other non-Saccharomyces yeasts, lactic acid bacteria, and acetic acid bacteria.  The yeasts often produce the same types of off characteristics that can be produced bySaccharomyces but certain species are more likely to produce these off characters due to their metabolic preferences. Brettanomyces (Brett) is an exception to this in that it also produces some off characteristics not associated withSaccharomyces. While these off aroma compounds are sometimes produced by other wild yeasts, Brettanomyces is unique in its ability to survive and grow in most wines, even after bottling. Some of the major off aroma compounds produced by bacteria, such as acetic acid and ethyl acetate, are also produced by yeast.  However, bacteria are also able to produce entirely different types of off characteristics in your wine than yeasts.  The metabolic properties of the bacteria and the environmental conditions in the wine determine what types of compounds they will produce.