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The management of alcoholic fermentation is a complex process dependent upon several key factors such as proper nutrition, reducing stress conditions and favoring growth and dominance of fermenting yeast.

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The management of alcoholic fermentation is a complex process dependent upon several key factors such as proper nutrition, reducing stress conditions and favoring growth and dominance of fermenting yeast.

Temperature plays an important role in winemaking by affecting yeast metabolism, yeast growth rate, fermentation kinetics and wine composition. Fermenting at high temperatures promotes the evaporation of undesirable volatile compounds such as methoxypyrazines, responsible for green herbaceous characters, often found in Cabernet Sauvignon, Merlot, Cabernet Franc and Sauvignon Blanc wines. At high temperatures, enzymatic activities are accelerated, thus more aromas are produced and more polyphenols are extracted. Secondary products like glycerol, acetic acid, succinic acid and acetaldehyde also increase as fermentation temperatures rise.

Challenges of High Temperature Fermentations
As temperatures increase, yeast viability and resistance to stress conditions decrease, leading to poor yeast populations, unhealthy yeast cell walls and premature yeast cell death, resulting in fermentation problems.


The Enartis Strategy for Managing Fermentations at High Temperatures

1.        Select a yeast strain adapted and resistant to high temperatures. Continuing the tradition of isolating, characterizing and preserving indigenous microflora from selected vineyards, Enartis USA isolated from the top Cabernet Sauvignon block on DAOU Mountain (Adelaida Appellation, Paso Robles) a thermo-tolerant Saccharomyces cerevisiae that could “handle higher temperatures during fermentation and lead to more color and flavor while helping balance tannins” as stated by Daniel Daou, co-proprietor and winemaker of DAOU Vineyards & Winery, Paso Robles. Recommended for high-end red wine production, Enartis Ferm D20 produces powerful, complex, and structured wines, with high ageing potential. It tolerates high fermentation temperatures (up to 100°F), while promoting the extraction of phenolic compounds, reducing the perception of green notes and enhancing aromatic intensity and complexity.

2.       To ensure a good and complete fermentation and promote aroma production, it is important to follow a good nutrition strategy:

·         At inoculation, use Nutriferm Arom Plus, a blend of amino acids, vitamins, mineral salts and a high content of amino acids selected for their aromatic precursor potential. It provides essential nutrients for proper yeast development and reinforces yeast resistance in extreme fermentation conditions.

·         At 1/3 of sugar depletion, as yeast becomes stressed and their fermentation abilities altered, use a complex nutrient such as Nutriferm Advance. Composed of organic and inorganic nitrogen, yeast cell walls and cellulose, it helps yeast with stress resistance, it detoxifies wine, ensures complete fermentation and reduces production of H2S. At this step, oxygen is important as well to help yeast cells build fluid and healthy membranes.

·         As soon as fermentation kinetics slow down, provide sterols and unsaturated fatty acids to improve yeast cell wall integrity, fluidity and activity. Nutriferm No Stop is a nutrient composed of yeast cell walls selected for their high content of unsaturated long-chain fatty acids, sterols, micronutrients and vitamins. The long-chain fatty acids and sterols are integrated into the yeast cell membrane and improve the fluidity, permeability and resistance to stress factors. Micronutrients and vitamins help to minimize the production of H2S and off-aromas. The insoluble portion of yeast cell walls adsorb toxic substances present in wine.

  1. Control temperature of cap and juice. When fermentations hit temperatures between 91-93°F, it is likely that cap temperatures exceed 100°F. It is important to record cap temperatures and use pump-overs, delestage or punch-downs frequently to reduce temperatures. From 5°Brix to the end of fermentation, keep the temperature between 70-80°F.


Enartis Interview with Daniel Daou, Co-Proprietor and Winemaker of DAOU Vineyards & Winery

E: What was your primary motivation for isolating Enartis Ferm D20?

DD: “My first desire was to create a yeast that could actually tolerate higher temperatures in excess of 100 degrees and not have a stuck fermentation.”

E: What made you chose Enartis Ferm D20 among the other isolates?

DD: “Not only did D20 have a higher glycerol level, not only did it have a lower alcohol level, not only did it dry up better, not only did it have lower VA numbers and higher TA, but the biggest thing that we saw is that it generated stable color quite a bit more than all the other yeasts.” 

E: How would you integrate the Enartis Ferm D20 in your winemaking strategy?

DD: “Starting this year, we will pretty much be using it for the majority of our grapes. We only tested on Cabernet, but I would think it would be the same for most other varietals.”

Source: WBM, August 2016, p30-31

If you have any questions, or would like to know more about our yeast and nutrition strategy, please give us a call at (707) 838-6312.

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