Wyeast Liquid Cultures for

Malolactic Fermentation

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Keep refrigerated. These cultures are fresh.

Let's get fermenting

Wyeast is a home-brewed, family-owned business located in the heart of Oregon’s scenic Columbia River Gorge. Established in 1986, our mission is to inspire home enthusiasts by providing fresh, pure, pitchable liquid yeast and cultures.

This package contains fresh liquid Oenococcus oeni cultures that are ready transform your wine. A successful malolactic fermentation with healthy lactic acid bacteria will balance and soften your wine while enhancing flavor and aroma characteristics.

How much yeast do I need?

One Oenococcus oeni package will inoculate 6 gallons (22 liters) of must or wine. Malic acid to lactic acid conversion is generally completed within 1-3 months.

Ready to Ferment



Remove from refrigeration. Allow package to come to room temperature (70 °F or 21 °C) just prior to use.


Sanitize the package before opening.


Give the package a good shake, tear it open, and pour into 6 gallons (22 L) of wine, must or juice that has completely or nearly completed alcoholic fermentation, or co-inoculate once primary fermentation has begun.


Maintain fermentation temperature or cellaring temperature based on the strain or blend selected. Malolactic Fermentation is generally complete within 1-3 months.

Select your

Fermentation Temperature

Adjust your fermenter to your desired temperature for the strain or blend. Learn more about Temperature.

  • For Malolactic Fermentation

  • For Alcoholic Fermentation

More Information

Product Description

A liquid suspension of Oenococcus oeni malolactic bacteria grown in a sterile, nutrient-enriched organic juice medium.

Wyeast’s Premium Liquid Malolactic cultures for Home Winemaking products include pure and blended cultures of the species Oenococcus oeni.

  • Sterile Packaged
  • UV Light Barrier
  • Keep Refrigerated
  • Do Not Freeze

Best By Date

This product performs best when used by the Best By date when stored between 34-40 °F (1-4 °C) and used following the instructions here. We calculate our Best By date according to the true age of the yeast and bacteria as determined by our microbiologists, and not simply by the date the product was packaged. This method provides consistent, reliable Best By dates and a minimum of 6 months of shelf life under our product warranty.

Packages close to the Best By date and packages that have experienced temperature fluctuation may take more time to begin fermentation. It is recommended to pitch an additional package if the product is within 60 days of the Best By date. Do not make a starter for blended cultures.

Product Warranty

We guarantee the integrity of our yeast & cultures for a minimum of 6 months, assuming they have been properly shipped, stored, and handled. Our packaging material provides 100% oxygen barrier and UV light protection making this guarantee possible. During the guaranteed shelf life, some loss of viability is to be expected. This will vary from one strain to another. However, the rate of viability loss is significantly less than many outside sources claim.

Packages will sometimes swell slightly during shipping, or later while properly stored. This is not an indication of deterioration if the package is within the Best By date. This is due to trace amounts of residual fermentables at the time of packaging being consumed by very active yeast. The cells produce some CO2 during this process, also known as “off gassing,” and cause the package to swell. Some strains are more prone to this than others.

Intended Use

This product is designed and intended for home-scale fermentations and is not warranted for the use in commercial application beyond pilot testing. This product is not for propagation or remanufacturing.

Certified Kosher

All Wyeast Laboratories, Inc. products are certified Kosher by the Orthodox Union.

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