Malo-Lactic Fermentation Guidelines

Improve wine quality with more rapid and complete malo-lactic fermentation

Malo-lactic Wine Cultures Wyeast # 4007
Leuconostoc oenos
ER1A
Ey2d

Fresh liquid cultures of L. oenos ERlA and Ey2d provide rapid and complete malic acid to lactic acid reduction to balance and soften wines. ERlA and Ey2d perform well in conditions of low pH and cool cellaring. Typical conditions of high wine acidity can be improved by reducing the harsh, sharp malic acid in the wine to the softer and smoother lactic acid. Other flavor improvements including vanilla and buttery notes can be anticipated. Natural occurring malic acid bacteria on fruit may be of inferior quality or quantity to complete malo-lactic fermentation.

Vintner's Choice malo-lactic cultures are suitable of pH 2.9 or greater and cellar temperatures as low as 55oF. See the reverse side for more advanced information.


 


 

Malolactic Cultures LabelBulletHome Winemaking guidelines for preparing malo-lactic starter cultures

We recommend an inoculum size of 1-2% by volume. One liter of culture will inoculate 30 gallons of juice at the 1% level or 15 gallons juice at the 2% level.

Use 4 ounce package for 5 gallons of wine or prepare a starter if larger volumes are to be inoculated.

 

  1. We recommend an innoculum size of 1-2% by volume. Four (4) ounces of culture will inoculate 3 gallons of juice at the 1% level or 1.5 gallons juice at the 2% level.

     

  2. The juice used should be low in sulfur dioxide (less than 15 ppm as free SO2), moderate in pH (no less than 3.3), and low to moderate in sugar content (19-20o Brix) for rapid cell growth. The juice can be diluted with water to lower the free SO2 or the sugar content but be sure the water you use is free of chlorine (e.g. well water, deionized or distilled water.) The pH can be raised by addition of calcium carbonate to the juice (0.35 grams CaCO3 per gallon of low pH juice will raise the pH by about 0.25 units).

     

  3. The addition of .01% by weight of yeast extract to the juice will help stimulate fast growth and high cell counts (.01% equals about 0.4 grams per gallon of juice).

 

  1. As long as the free SO2 level is less than 15ppm the bacteria innoculum can be added with the yeast innoculum. Otherwise wait 1-2 days after yeast addition before adding the bacteria cultures. ( In any case check the free SO2 level).

     

  2. Maintain the juice temperature at 65-70o for rapid growth of the bacteria.

     

  3. Monitor the progress of the malo-lactic fermentations with paper chromatography. When the malic acid spot begins to disappear (10-14 days) the cultures are ready to inoculate larger batches of wine.

     

  4. Inoculate larger lots with 0.5 to 2.0% by volume with the starter cultures (1/2 gallon to 2 gallons of culture per 100 gallons of wine). Wines can successfully be inoculated at any time during or after the yeast fermentation provided the free SO2 is low (15ppm free or less) and the temperature is maintained at a moderate level.

 

Overall the fermentations will normally go to completion in 2-3 months.

 

Commercial Evaluation of Two Oregon Strains of Malo-Lactic Bacteria


The performance of two strains of Leuconostoc oenos, Er1a and Ey2d, isolated from Oregon wines was evaluated in experimentally and commercially produced wines.
Experimental lots of Chardonnay, Pinot Blanc, and Pinot Noir were inoculated at the end of yeast fermentation at 18°C with approximately 106 cfu/ml of Er1a, Ey2d, ML-34, PSU-1, MLT-kli, and BB44-40. Under low pH conditions, the Oregon strains completed  Malo-Lactic fermentations (MLF) more rapidly than the other commercially available strains: at pH less than 3.3 Er1a completed MLF in an average of 48 days, Ey2d in 94 days, MLT-kli in 127 days, and the other strains in 143 days or longer. At pH greater than 3.4 all the strains completed MLF within 31 days. Commercial wines were inoculated during yeast fermentations with 0.5 to 2.0% V/V Er1a and Ey2d grape juice cultures (109 cfu/ml) and wine cultures (108 cfu/ml).

Er1a completed MLF in 1-2 months at cellar temperatures of 15°C or higher, but was sensitive to cooler temperatures.

Ey2d was more cold tolerant and completed MLF in 2-3 months at temperatures in 12-15°C. In addition, Ey2d retained Malo-Lactic activity at temperatures as low as 8° C when all other strains including Er1a were inactive.