South Africa Wine Technical Yearbook 2025

FIGURE 10. Brettanomyces and volatile phenols measured in a Merlot (Bordeaux, France) with SO 2 and without SO 2 but with LEVEL 2 SALVA™.

three replicates for each). The first modality (“Control”) was inoculated with Saccharomyces cerevisiae and fermented at a temperature below 27°C. The second modality was inoculated with LEVEL 2 SALVA™ for 48 hours before Saccharomyces cerevisiae inoculation. At the end of alcoholic fermentation, both 4-ethylphenol and 4-ethylguaiacol were in lower concentration in the modalities with LEVEL 2 SALVA™ compared to the control (Figure 8). 5.4 Reduction in SO 2 usage with LEVEL 2 SALVA™ An experiment was conducted with the Università Degli Studi di Udine on Cabernet Franc. After crushing and destemming, the must with skins was homogeneously split into three 25-L tanks where Brettanomyces was inoculated at a level of 1 x 10 3 CFU/mL. A control with no addition was compared to a SO 2 addition of 2.5 g/hL and an addition of LEVEL 2 SALVA™ (with no SO 2 addition). At the end of the alcoholic fermentation, volatile phenols were analysed. Levels of 4-ethylphenol and 4-ethylguaiacol were higher in the control with neither SO 2 nor LEVEL 2 SALVA™. In this experiment, LEVEL 2 SALVA™ was more effective than SO 2 as it reached the lowest level of volatile phenols (Figure 9). Another trial was conducted on a Merlot, in Bordeaux, France, comparing 5 g/hL of SO 2 addition

to an addition of LEVEL 2 SALVA™ (with no SO 2 addition), both added at tank’s filling (80 hL stainless steel tanks) before a cold soak (four days at 10°C). A follow-up at different stages (end MLF and five months after) showed the presence of Brettanomyces at the end of MLF and significant growth five months after, during ageing, in the control treated with 5 g/hL of SO 2 . No Brettanomyces were detected in the wines with LEVEL 2 SALVA ™, neither after MLF nor five months after. This inhibition of Brettanomyces by LEVEL 2 SALVA™ was correlated with the absence of volatile phenols in the LEVEL 2 SALVA™ treatments (Figure 10). 6. An integral bioprotection approach to control Brettanomyces Even at levels below their perception threshold, volatile phenols can negatively impact the sensory profile by reducing the fruit perception, masking the wine identity and its terroir signature. At higher concentrations, it clearly leads to a qualitative depreciation of the wine, with the presence of obvious defaults. Different natural solutions for grapes until the final wine during ageing can help to manage Brettanomyces contaminations. LEVEL 2 SALVA™ is a specific bioprotection solution that complements existing natural solutions.

inoculation. Both tanks followed the same winemaking process, and the wines were analysed at the end of the malolactic fermentation (MLF). Wines where LEVEL 2 SALVA™ was inoculated at early stages showed a very low level of Brettanomyces population was found (Figure 6). 5.2 Addition of LEVEL 2 SALVA™ on harvested grapes LEVEL 2 SALVA™ can also be applied in earlier stages of wine production, more specifically on the harvested grapes. A trial in Spain was conducted in which LEVEL 2 SALVA™ was applied by spraying on Tempranillo grapes that had been hand-harvested, compared to grapes without any addition. The same winemaking process was applied for both treatments. At the end of MLF, we observed that LEVEL 2 SALVA™ was able to efficiently limit the development of Brettanomyces (Figure 7), decreasing its population by a factor of 2.4. 5.3 Early contamination of Brettanomyces : efficiency of LEVEL 2 SALVA™ An experiment was conducted in the laboratory of Microbiology of the Fondazione Edmund Mach (San Michele all’Adige, Italy) in a liquid red grape must (Rebo grape variety), inoculated with Brettanomyces at 1 x 10 3 CFU/mL. After 12 hours, two modalities were performed (1 L bottle,

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TECHNICAL YEARBOOK 2025