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WINEMAKING Upsides of Wild Fermentation New, cultured yeast combinations seek to mitigate the risks By Jean L. Jacobson County, Calif. With more than 140 par- ticipating wineries to choose from, I opted to stop at wineries I had never visited but knew by reputation for the quality of their Zinfandels. The time flew quickly, but the wineries I did visit were well worth the effort. D As a former winery lab manager and cur- rent winemaking consultant, I was particu- larly interested in hearing the winemaking stories, especially when the subject of wild fermentations came up (OK, I brought it up.) My focus was whether winemakers used commercial cultured yeast, and if they have tried the new yeast products cultured from "wild" non-Saccharomyces yeast or Saccha- romyces hybrids. The majority of these new yeast products are cultivated from Torulaspo- ra delbrueckii and are used in sequential inoculations with Saccharomyces cerevisiae. Nature harbors a plethora of wild yeast species and subspecies, both Saccharomyces and non-Saccharomyces. The mix is differ- ent from vineyard to vineyard and year to year, depending on the soil pH and nutrients, altitude, moisture content, sulfur use, etc., uring the second weekend in January, the winery and lodging association Wine Road held its 20th anniver- sary event, "Winter Wineland 2012," in northern Sonoma "I observe, smell and look under the (micro)scope every day… primarily (for) ." —Winemaker Antoine Favero, Mazzocco Winery Highlights • Reducing winemaking risks allows vint- ners to reap the benefits from a "wild" yeast fermentation. • Cultured yeast producers are isolating "wild" non-Saccharomyces yeasts for the winemaking market. • Shopping for your blend profile of ideal "wild" yeasts may not be that far into the future. 34 Wines & Vines APRiL 2012 plus the aggressiveness and population of the dominant yeasts. Non-Saccharomyces yeasts include Pichia, Kloeckera, Candida, Zygo- saccharomyces, Dekkera, Hansenula, Toru- laspora, Brettanomyces and Hanseniaspora. In addition to yeasts, incoming fruit also will carry molds, Lactobacillus and Acetobacter. In Thomas Ulrich's June 2011 article "The Secret Life of Feral Yeast," he refers to Uni- versity of California professor and geneticist Dr. Linda Bisson's comments about wild yeast populations. According to Dr. Bisson, the yeasts Kloeckera apiculata and Hanse- niaspora uvarum are the most common yeasts found on incoming grapes at concentrations of 65% to 80% of the total yeasts isolated. Pichia and Candida yeast species have been shown to be approximately 10%, while Saccharomyces yeast populations are far fewer, numbering approximately 1 in 10 million yeasts. Ulrich quotes winemaker Greg La Follette as saying that Kloeckera, Hanseniaspora and Candida dominate the early stages of fermentation, and Pichia drives the fer- mentation when the ethanol concentration reaches 3% to 4%. La Follette said at the time, "The finishing yeast is always S. cer- evisiae, which can tolerate higher concen- trations of alcohol." It seems to me that a winery having great wild fermentations would benefit from know- ing the types of yeasts that drive their fermenta- tions. Acorn Winery owner and winemaker Bill Nachbaur in Healdsburg, Calif., has had great success with his wild fermentations but said he is not in a rush to identify the yeast. He related a story he heard about an Australian winery that had strong, vigorous and fast fermentations. Since the winery did only wild fermentations, they were curious and had their wild yeasts identified; tests identified S. cerevisiae as the predominant yeast. The cultured yeast was be- ing introduced into the winery by bees carrying it over from the neighboring winery on their bodies. Evidence of previously used cultured yeasts can frequently be found in wineries regardless of the level of sanitation. Wherever the yeasts come from, the vineyard or winery, a growing number of winemakers feel strongly that wild fermen- tations are the only way to go. Conversely, many winemakers feel just as strongly that a wild fermentation is much too risky. What are the major issues? The downside of wild fermentations I believe the foremost downside is time— time involved in the primary and second- L actobacillus