Native Yeast: Also known as indigenous, ambient or wild yeasts, these are yeasts that occur naturally on the grapes or in the cellar, rather than commercially cultured yeasts; both are used for fermentation. Some argue that native yeasts are more authentic, but most producers favor the reliability of cultured yeasts.
Yeast: Micro-organisms that convert sugar to alcohol and carbon dioxide in the process known as fermentation. The predominant wine yeast, saccharomyces cerevisiae, is the same micro-organism that ferments beer and makes bread dough rise.
Inoculation: The process in which a winemaker introduces yeast to the must to kick-start fermentation.