WINE YEAST by Jack Costa
Number of cells in a human body: 37 trillion. Number of cells in a yeast body: 1. Ironically, the 37 trillion celled winemaker would nd themself somewhat unemployed if the 1 celled yeast did not exist. And while most people have a rough understanding that these one-celled yeast perform some kind of mysterious voodoo magic to cause bread to rise and wine grapes to ferment, they may not be aware that these fungi do much more to wine than simply convert sugar into alcohol. This begs the question; who’s the real winemaker: man or yeast? Yeast: not just about the alcohol The yeasts used in winemaking are generally cream-colored, round, or sometimes slightly ovular in appearance. The yeast strain considered the gold standard for winemaking
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called “Saccharomyces cerevisiae,” a Latin phrase that translates literally as “Sugar Fungus” (no explanation is needed for why the Latin translation is still preferred). And while the primary role of yeast is to convert sugars into alcohol, these fungi are also responsible for several other chemical processes that signi cantly a ect the avor and structure of wines. Yeast accomplishes this winemaking feat by interacting with the acids, alcohols, and solids contained in the fermenting grape must. In doing so the yeast can actually synthesize new avor compounds by altering the chemical composition of the grape juice. Many of these additional aromas and avors created by the yeast can be unique to particular grape varieties. For example, Viognier grape juice contains compounds necessary for producing isoamyl acetate, a chemical known for smelling and tasting like bananas. A winemaker can utilize a yeast strain known for producing higher amounts of isoamyl acetate to craft a wine with extra banana notes which is a hallmark of Viognier. Listed below are several examples of chemical compounds and their resulting avor pro les. Each of these compounds can be enhanced depending upon the selection of speci c yeast strain.
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13 | MICHIGAN UNCORKED
