The Mycology of Wine (#171)
Wine is a fungal product derived from grapes that has been with us since the dawn of civilisation. Apart from the Noble Rot form of Botrytis cinerea, which produces the Sauternes style of wine, filamentous fungi are principally grape spoilage microorganisms. Unicellular fungi, in particular the fermentative yeasts, are the principal fungi in winemaking. In natural, spontaneous, fermentations the microflora is complex with many, diverse, species impacting on the fermentation and wine quality. Members of the Saccharomyces sensu stricto clade, especially the species S. cerevisiae and S. bayanus, predominate during fermentation due to their special adaptation to the fermenting grape must environment, despite the fact they do not colonize the surface of intact grape berries. In recent decades it has become common practice to inoculate grape juice with a single, robust wine strain of S. cerevisiae; this takes some of the risks out of relying on the natural microflora to complete fermentation and it minimises the risk of spoilage. However, the more we learn about the beneficial effects of a diverse microflora on wine quality the more we are looking to natural mircroflora of a wine fermentation to develop improved inoculation and fermentation management strategies.