Issue link: http://winesandvines.uberflip.com/i/131907
winemaking and normal SO2 levels). Once their lab procedures were realigned to focus on Zygosaccharomyces (and other wine-tolerant microbes, though those were seldom if ever found), the impossible workload was reduced dramatically, and nearly all wines could be released on time. B3—Large wineries need a trained wine microbiologist A large winery had recurring difficulties with Zygosaccharomyces, and some packaged wine exploded after release. After attending seminars on wine microbes, and in-house consultation, the winery microbiologist learned to recognize which colonies should be checked by PCR to determine if they were Zygosaccharomyces. A "find-thebug" swabbing procedure was done on the most problematic bottling line (Figure 4), and sanitation protocols were changed to eliminate as many instances of bottling line contamination as possible. Zygosaccharomyces still infects some of the packaged wines, but the microbiologist can determine which wines need to be held or rebottled. Case Histories for Protocol C C1—Unnecessary rebottling A medium-size winery, located far Figure 4 — Swabbing bottling line to locate microbes. from any enology lab, sent bottled wine samples to a local food lab that reported results as numbers of colonies of yeast, bacteria or mold, with no further identification. If any microbes were found, the winemaker would then rebottle the wine, sometimes more than once. When the winery learned to do their own culturing and to distinguish wine-tolerant microbes from wine-intolerant ones, the unnecessary rebottlings stopped. Another choice would have been to use an enology lab instead of a food lab, despite the transit time. The current winemaker has not had to rebottle any wines in the past 20 years. C2—No one knows what lab results mean A winery sent samples routinely for a Scorpions panel. Pediococcus was always detected in one stuck Chardonnay. No one at the winery knew what that meant, so they filed the results without asking if Pediococcus could become a problem. It was only when the wine acidity increased (from sugar metabolism) and became cloudy (they do not sterile-filter) that they investigated what Pediococcus could mean to their wine. C3—Red herrings The microbiology director for a winery group cultured a bottled wine that had become active in the bottle. There were several large, colorful colonies with a faint, colorless background haze and three tiny white colonies (Figure 5). They were worried about the large, ugly colonies, but the real problem was the haze (Oenococcus oeni) and the three little white colonies (Pediococcus). The big colonies were "red herrings." Figure 5 — Large non-wine colonies with three small white Pediococcus colonies (one circled) and a background haze of Oenococcus oeni. Which protocol is best? My recommendations are: Protocol A for very small wineries where one person may perform many tasks and Protocol B when different departments do different jobs. Protocol C is not recommended for wineries. Training of all personnel is recommended, including sales people, to watch for danger signals in cellared and bottled wines. Even bottle variation noticed by tasting room staff can be important, as it can be the first sign of microbial growth. Each winery must determine which protocol to choose, but the choice should be made deliberately, with reference to the winery's size, cellar layout and equipment, personnel structure and types of wine. PWV 60 p EVQ_ENARTISFERM PRIMITIVO_W&V tr.inddNE 20 13 racti c al w i ne ry & v i n e yard J U 1 11/04/13 17:10