Stuck Malolactic ferments
We have seen a few stuck Malolactic ferments this year. Now everything is warming up it is time to get on to these troublesome secondary ferments. (As well as a few stuck primary, but one problem at a time).
Delayed Malolactic Fermentation (MLF) in winemaking poses risks such as microbial instability, potential oxidation, increased volatile acidity, unbalanced acidity, and reduced complexity, These risks can impact wine quality, flavor, and stability, emphasizing the importance of monitoring MLF progress and taking corrective measures to ensure timely completion for desired wine characteristics and safety.
Factors Affecting MLF Performance:
Wine temperature, acidity/pH, alcohol level, and sulfur dioxide (SO2) levels can affect MLF performance.
Ensure that the MLF protocol you use is suitable for these parameters.
Wait at least seven days after adding lysozyme or similar product or copper before initiating MLF to allow its inhibitory effect to subside.
The yeast selected for primary fermentation can impact MLF performance.
MLF Methods:
Spontaneous MLF initiation can be risky due to limited control and potential spoilage/contamination.
Direct inoculation cultures like Viniflora® can be added directly to wine or must for reliable and robust MLF initiation.
Impact of Grapes/Must/Wine:
High sugar and alcohol levels can inhibit MLF, requiring suitably aligned cultures
Metabolites from grapes, including amino acids and vitamins, are essential for MLF bacteria.
Bactiv-Aid 2.0 can provide necessary nutrients, especially if MLF is delayed or carried out after racking off yeast lees.
Medium-chain free fatty acids (Decanoic and Dodecanoic acids) can inhibit MLF and should be controlled using Bactiv-Aid 2.0.
Low initial malic acid levels can make initiating MLF difficult.
Managing a Stuck MLF:
Stuck MLF should be treated promptly to avoid low SO2 levels and the risk of oxidation or spoilage.
Compatibility between the culture and the stuck wine’s parameters (alcohol, temperature, pH, and total SO2 levels) is essential.
Ask us to check your sample. The parameter most often out is TSO2.
Adaptation:
Involves inoculating a suitable starter culture in another wine (not the stuck wine) along with a nutrient source.
The stuck wine is gradually added to the inoculated mixture, and the process can be time-consuming.
The starter culture used should be compatible with the stuck wine parameters.
Re-inoculation:
The most straightforward method for restarting a stuck ferment, especially when a spontaneous MLF was initially used.
Ensure the stuck wine is at the correct temperature.
Add Bactiv-Aid 2.0 for nutrients and use a Viniflora® culture that matches the stuck wine’s parameters.
Mix the wine and culture thoroughly.
Properly addressing stuck MLF is essential to maintain wine quality and avoid spoilage. Winemakers should carefully assess the specific conditions and parameters of their wine to choose the most appropriate method for restarting MLF.