Issue link: https://digital.copcomm.com/i/913027
{ SOMMjournal.com } 55 "In sites that are farmed sustainably, we find anywhere from 1,000–1,200 microorganisms, the majority of which are bacteria." IMAGE COURTESY OF SAKKMASTERKE VIA THINKSTOCK which could include expressions of mineral- ity. The definition of minerality continues to be a moving target, as only a handful of compounds are known to contribute mineral flavors in wine. Cifuentes and Belda use a modified spider graph to chart the organo - leptic properties of wine and have correlated the presence of Saccharomyces bayanus, a yeast with increased mineral expression. "The mystery is in the bugs," said Cifuentes. "We just don't know what they're doing. It's very likely they are dropping a lot of compounds we haven't yet been able to isolate." During the fermentation process, a suc - cession of different groups of bacteria and yeast interact and then expire. The resulting flavors in the wine are a direct result of the diversity, length, and conditions of the fermentation. "The more bugs you have to begin with, the more potential you'll have for diverse chemical compounds in the fin - ished wine," says Cifuentes before pointing out that winemaking practices can promote or suppress that diversity (for example, allowing malo lactic fermentation to occur naturally in red wines as the cellar grows warmer in the early months of spring, ver - sus an inoculated malolactic fermentation that takes place alongside or immediately after the primary fermentation). Citing a producer in Spain who lets malo- lactic fermentation (MLF) occur naturally in his red wines, Cifuentes says the practice results in a significantly different flavor pro - file—one that has more terpenes and more mineral expression, as well as a velvety tex- ture that doesn't require oak aging or the use of sulfur. These desirable characteristics are attributed to a thermo-resistant strain of lactobacillus and a host of other bacteria that can act in colder conditions over a longer period of time. "The organoleptic properties of these wines are judged to be far superior to wines that have been put through MLF immediately after primary fermentation," Cifuentes adds. With all of the marketing around native yeast fermentations, having a better understanding of what yeasts other than Saccharomyces cerevisiae bring to the flavor profile of finished wine is key. By analyzing the sensory contributions of non-Saccha - romyces yeast through DNA sequencing, Belda has found that native yeast fermenta- tions contribute increased complexity—a winemaker who uses native fermentation can attest to this—and help stabilize wine. At the University of Milan, Italian researchers are shedding new light on the role yeasts play in the vineyard. Yeast strains found on wild grapes, most notably Meyerozyma guilliermondii, have potential for use as a biocontrol in combating molds like Botrytis cinerea and sour rot. Field trials are underway to confirm what properties, if any, these wild yeasts strains contribute to fermentation, as well as how effective they are in maintaining checks and balances in the vineyard.