Wines & Vines

July 2015 Technology Issue

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62 P R A C T I C A L W I N E R Y & V I N E YA R D July 2015 W I N E M A K I N G exploring the impact of different poly- phenolic fractions on MLF. 5 Polyphenolic extracts were prepared from Merlot, Cabernet Sauvignon and Tannat and added to Chardonnay wine at the same level present in the red wine from which they were extracted. Results are shown in Figure 1. MLF was completed in 13 days in the control, but between 1 and 1.5 g/L of L-malic acid remained in the wine that received polyphenolic extracts. The poly- phenolic extracts caused a significant slowing of L-malic acid degradation. W inemakers are aware that Oenococcus oeni bacteria, tradi- tionally responsible for malo- lactic fermentation (MLF), are successful only if they can adapt to the harsh environment of a fermenting must or a finished wine. The known complex nutritional require- ments of wine lactic acid bacteria (LAB) and the use of tools to facilitate the onset and progress of the MLF when nutrient availability is limiting were discussed in Part I of this report. LAB are capable of growth under harsh conditions in wine because of a dynamic bal- ance between com- ponents that both favor and inhibit their growth and survival. Polyphenols can exert stimulating or inhibiting effects on bacterial growth and activity depend- ing on the strain, as well as the nature and concentration of the polyphenols tested. 1,2,4,6 Many wine polyphenols are combined with other compounds that tend to mini- mize their toxic or inhibitory effects, thus allowing the MLF to proceed. In wines that contain a large proportion of condensed tannins, a strong inhibition of MLB is observed. 3,7,8 Trials were conducted with the goal of Managing nutrition of wine bacteria to minimize the effect of inhibitors Part II *Magali Déléris-Bou, **Sibylle Krieger-Weber, Ph.D. and ***Goran Milanov, Ph.D. *Lallemand bacteria lab manager, Toulouse, France, **Lallemand bacteria R&D manager, Korntal-Münchingen, Germany, ***associate professor at Institut of Agriculture Skopje at University St. Cyril and Methodius Skopje, Macedonia BY Figure 1. Effect of polyphenolic extracts. 5 CS1 CS2 CS3 T Control 2.5 2.0 1.5 1.0 .5 0 Malic acid (g/L) 0 5 10 15 Days CS1, CS2, CS3 - Cabernet Sauvignon Extracts; T - Tannat Extract OPTI'MALO ™ BLANC ML RED BOOST ™ For fast and secure Malolactic Fermentation www.lallemandwine.com Scott Laboratories: 707 765-6666 – info@scottlab.com – www.scottlab.com Energize your selected wine bacteria

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