What are the principal factors influencing the development of Lactic Acid Bacteria (LAB)?
The biggest factors to consider for MLF success include pH, temperature, alcohol and SO₂ (Free and Total). These four parameters have a negative synergistic effect, making the completion of MLF difficult when combined. Additionally, vineyards sprays, initial malic acid levels, yeast strain used for alcoholic fermentation and wine polyphenol content can be stress factors. Problems can arise when pH is low (<3.4), alcohol is high (>14.5%), wine temperature is low (<65°F) or high (>80°F), total SO₂ is high (>50 mg/L) and/or free SO₂ is high (>10 mg/L).

Does LAB strain choice really matter?
Choosing the appropriate LAB strain for MLF is important for both wine quality and style parameters. An inoculation with selected Oenococcus oeni strain reduces the potential for spoilage by other microbes by ensuring a rapid onset of MLF. LAB also contribute aromatic and mouthfeel changes through MLF. This means the selection of the appropriate strain gives the winemaker better control over aromatic and mouthfeel production. Below are the Oenococcus oeni strains offered by Enartis USA: 

• Enartis ML One has a moderate conversion speed, produces clean and fruit forward aromas and helps reduce herbaceous characters.
• Enartis ML Silver: Due to its resistance to alcohol, SO₂ and high phenolic content, Enartis ML Silver ensures a fast and complete MLF even under difficult conditions.
• Enartis ML MCW, isolated from the Sonoma area of California, has been selected for its ability to produce creamy, “buttery” wines. High tolerance to low temperatures, low pH and high alcohol levels, Enartis ML MCW is suitable for MLF under difficult conditions. 

Are nutrients required for MLF?
As with any micro-organism, Oenococcus oenineeds specific nutrients and growth factors to develop healthy cells and conduct and complete MLF. Post-alcoholic fermentation wines are usually nutrient deficient, lacking sufficient and appropriate amounts of amino acids. Yeast lysis does release nutrients into wine, but it is a very slow process which can take up to six months after alcoholic fermentation. Nutritional depletion is one of the main causes of stuck/sluggish malolactic fermentations.
Enartis Nutriferm Osmobacti is an osmotic pressure regulator and nutrient that improves the survival rate of the bacteria during rehydration and activate their metabolism.
Enartis Nutriferm ML provides essential nutrients specific for LAB and polysaccharides to absorb compounds that may inhibit cell growth. It helps them colonize wine and complete MLF.
Using these two nutrients will drastically improve chances of MLF completion. 

What about the production of diacetyl?
Produced by LAB, diacetyl is associated with buttery notes. The entire winemaking process impacts the production of diacetyl.
To increase the production of diacetyl in wine:

• Use Enartis ML MCW
• Promote slow MLF speed with low inoculation rate and low temperature
• Reduce lees contact with racking
• Use Enartis Stab Micro or SO₂ when MLF completes and desired diacetyl levels are reached: living yeast and bacteria can break down diacetyl in an irreversible way.
• Promote slight oxidative environment with lees stirring or MOX
• Limit SO₂ use as molecular SO₂ can bind with diacetyl (this is a reversible reaction). 

To minimize diacetyl production during MLF:

• Use Enartis ML Silver, a fast fermenter with low ability to produce diacetyl
• Increase fermentation speed with higher inoculation rate, higher nutrient supplementation and higher temperature
• Increase lees contact by limiting racking, co-inoculation or early inoculation: living yeast and bacteria can break down diacetyl in an irreversible way
• Protect wine from oxygen to stay in a reductive environment
• Use antimicrobial such as SO₂ or Enartis Stab Micro to eliminate ML bacteria as soon as MLF is complete and limit the production of diacetyl 

For more information, please contact us at (707) 838-6312.