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3 6 V I N E YA R D & W I N E RY M A N A G E M E N T | N o v - D e c 2 014 w w w. v w m m e d i a . c o m wine chemistry and the microbial population to accurately assess risk," he said. "I look at the wine chemistry from a microbial point of view. Are conditions conducive to growth or inhibitory?" He recommends, at a minimum, analyzing the wine's pH and con- centration of glucose/fructose, long periods of time and may con- tinue to change a bottled product through their metabolism. Dr. Richard DeScenzo of ETS uses the results from Scorpions analysis along with wine chemistry data to help clients assess their risk of wine spoilage post-bottling. "It is critical to know both the malic acid, ethanol, and free and total SO2. Adequate molecular SO2 is criti- cal for control of microbial growth, with minimum recommended lev- els of 0.5 mg/L, which can be dif- ficult to achieve with a wine pH greater than 3.7. Glucose, fructose and malic acid can be utilized as car- bon sources by various microbes. The effect of ethanol and pH can be inhibitory or permissive of microbial activity, depending on their values and the actual microbes present. It is also important to perform microbiological analysis to iden- tify what microbes are in the wine. DeScenzo recommends Scorpions as a screening tool prior to filtra- tion, since "it quantifies specific target microbes and detects viable- but-not-culturable (VNC) microbes. Filtration plating has long been the analytical gold standard, but it does not detect microbes in the VNC physiological state, has a long turn-around time, and identification to genus and species of the viable organism that do grow is often pre- sumptive," he said. "Microscopy CROSSFLOW FILTRATION PURCHASE, RENT OR HIRE OUR SERVICES VOLUME CONTRACTS AVAILABLE VA Filtration crossfl ow systems are: Gentle on wine - low crossfl ow Cost effective - Starting at $22 500.00 Robust - 5 Year membrane life Inexpensive to maintain Manufactured in Napa County Available in manual, semi-auto and fully auto • • • • • • 707 552 2616 sales@vafi ltration.com www.vafi ltration.com 1000 gal/hr 200 gal/hr Rental Unit 500 gal/hr Other Services offered: VA Reduction, Alcohol Reduction, 4EP/4EG Reduction, wine concentra- tion, lees fi ltration, pH Reduction, smoke taint reduction, equipment design and manufacture. Richard DeScenzo of ETS Laboratories takes into account wine chemistry and microbial population when helping wineries asses their risk of post-bottling wine spoilage. SOIL & CELLAR REMI COHEN