Precision Fermentation: Biotech to balance Flavours, Acid and Alcohol
As warmer vintages widen the gap between ripeness and freshness, a new generation of selected yeasts lets winemakers rebalance wine during fermentation, not after.
· 2 min read
Warmer ripening can force winemakers to choose between aromatic and phenolic maturity and retaining acidity, with consequences for alcohol, pH and freshness. Excellence® Celsius redirects more sugar to glycerol, reducing alcohol by about 0.4–0.7% abv while producing malic acid; trials report higher acidity, lower pH and roundness. Excellence® X-Fresh enables stronger bioacidification, including through a dedicated ingredient tank for blending.
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For winemakers, warmer ripening widens the gap between technological maturity and freshness. Waiting for full aromatic and phenolic maturity raises sugar and lowers acidity at harvest; picking earlier to protect acidity can compromise flavour or phenolic development. The result is a familiar cellar trade-off: capturing ripe-fruit expression while keeping alcohol, pH and freshness in balance.
Conventional acidification and ion exchange remain effective, but advances in wine microbiology now let winemakers influence part of that balance during fermentation itself: selected yeasts can redirect sugar metabolism, produce organic acids and modify fermentation yield.
Excellence® Celsius: gentle rebalancing in the tank
Excellence® Celsius has a lower sugar-to-alcohol conversion yield than conventional S. cerevisiae, diverting more fermentable sugar toward glycerol. In trials this reduces final alcohol by approx. 0.4–0.7% abv while producing L-malic acid during fermentation, raising total acidity and lowering pH. The aim isn’t a ‘low-alcohol wine’, but more room to reach ripeness while moderating its alcohol-and-acidity consequences.
The added acidity also supports microbial stability and creates more favourable conditions for malolactic fermentation. The strain ferments robustly, with very low volatile acidity and SO₂, and adapts across warm-climate reds, white and rosé press fractions and sparkling bases – reducing the need for later acidity correction and saving cost.
Proven in the cellar
International trials on Chardonnay and Syrah show the effect: higher total acidity, lower pH, more glycerol and roundness, and reduced final alcohol.
Excellence® X-Fresh: targeted bio acidification
Where Celsius rebalances gently, non-Saccharomyces yeasts offer a more targeted route to pronounced acidification. Excellence® X-Fresh was developed specifically for this. In a 2025 Cabernet Sauvignon trial it lifted total acidity from 6.03 to 11.31 g/L while lowering pH from 3.59 to 3.32, a substantial, biologically driven correction.
Best applied under controlled sequential inoculation with an alcohol fermentation yeast, X-Fresh is used to strongly bioacidify a dedicated ‘ingredient’ tank for blending, maximising its potential while simplifying correction of larger volumes.
Complementary tools, one philosophy
Bioacidification is a practical additional tool for managing the ripeness, alcohol and acidity relationship. It is less about acidification itself than the flexibility it gives when maturity, sugar and style don’t align. Which tool fits depends on the size of the adjustment required:
Choosing the right tool
BioCraft: Agents for Lamothe-Abiet, Tonnelerie Radoux, Gauthier Freres, Pronektar, EP Minerals and Lake International
+27 21 872 8125 | [email protected] | biocraft.co.za
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