Malolactic fermentation (MLF) is crucial in winemaking for reducing acidity, enhancing flavor, and improving stability. By converting sharp malic acid into softer lactic acid, MLF softens the wine, creating a smoother, more palatable profile while also adding complexity, such as buttery or creamy notes, particularly in wines like Chardonnay. This process, which typically occurs after primary fermentation, also stabilizes the wine by preventing potential spoilage from spontaneous malic acid fermentation. MLF is common in red wines and some white wines and is often induced by inoculating the wine with a selected bacterial strain to achieve a specific texture, flavor, and overall quality of the wine.
MLF is much slower and less turbulent than primary (alcoholic) fermentation; taking weeks, even months, to complete. The fermentation is complete when malic acid levels are measured below 0.1 g/L.
Recommended practices for a successful MLF:
Identifying and Correcting a Sluggish Fermentation:
Malolactic fermentation can be a slow process, but sometimes it slows too much or stops altogether before the malic acid has been fully degraded. Below are recommended parameters to evaluate if the MLF activity seems to be slowing. Start by assessing the physicochemical state of the wine to ensure it is conducive to MLF. After evaluating the wine, assess the health of the bacteria. Sometimes a small intervention is all that is needed to get back on track.
If none of the above seem to work, it may be necessary to restart the stuck fermentation.
Restarting a Stuck MLF:
If MLF stalls and cannot be revived, it’s essential to remove any toxins and lees from the wine before restarting the process. Detoxifying the wine before MLF is a step often overlooked or assumed to be handled by yeast hulls, but taking this step significantly increases the chances of successful inoculation and helps ensure that MLF proceeds as intended.
ATPGroup offers an exclusive and comprehensive range of highly effective freeze-dried malolactic bacteria cultures, designed to meet virtually any MLF condition. Our unique production method introduces stress factors throughout the process, ensuring maximum activity upon inoculation.
For managing even the most challenging MLF conditions, the Malo-Plus and Malo-Plus HA strains, with their high alcohol and low pH tolerance, stand ready. If you’re aiming for the aromas and mouthfeel of moderate diacetyl levels, the Malo-D is your go-to choice. Seeking more complexity? Our multi-strain contender, Malo-Multi, is ideal. And for heightened complexity and enriched mouthfeel, Malo-Vigna excels even in the most trying circumstances. The Malo range is available in dose sizes ranging from 660 gallons to 100K gallons, to optimize dosage for all wineries.
The best strategy for effective completion of malolactic fermentation is to combine the strength of the Malo-Plus range with Malo Detox and Malo NutriBact ML nutrients. Pre-inoculation, Malo Detox curbs natural post-primary fermentation toxins and fosters a favorable microbial environment. Malo NutriBact, packed with natural yeast derivatives and micronutrients, propels a swift and thorough MLF, particularly in stress-laden wines.
For more information on our ML products or for help designing a protocol specific to your needs, contact your ATPGroup Enology Products Specialist or call (707) 836-6840.
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