Doing a Malolactic Fermentation (MLF) on a concentrate kit isn't just unnecessary—it can actually ruin your wine. Here is the breakdown of why kits and MLF don't mix.
What is MLF anyway?
MLF isn't actually a sugar fermentation; it’s a bacterial process. It uses Oenococcus oeni bacteria to convert sharp, green-apple-tasting Malic Acid into soft, buttery Lactic Acid (the same acid found in milk). It’s common for big, buttery Chardonnays or barrel-aged Cabernets.
Why it’s a "No-Go" for Kits
1. The Acid is Already Balanced
Wine kit manufacturers are masters of consistency. They’ve already adjusted the acidity levels in the concentrate to ensure the wine is balanced the moment it finishes fermenting.
The Risk: Since kits are naturally low in Malic acid, an MLF would strip away the "brightness" of the fruit, leaving the wine tasting flat, flabby, and thin.
2. Kits are "Pre-Stabilized"
Most wine kits include additives to ensure success for the home brewer. They often contain potassium sorbate or high levels of sulfites to prevent spoilage.
The Conflict: MLF bacteria are extremely sensitive. The stabilizers in the kit will usually kill the bacteria before they can even start working, leading to a "stuck" MLF that can create off-flavors like vinegar or "mousy" aromas.
3. Nutrient Deficiencies
When juice is concentrated and then reconstituted, it loses some of the specific micronutrients that Oenococcus oeni needs to survive. Without those nutrients, the bacteria struggle, and "stressed" bacteria produce bad smells.
The Takeaway
If you want that buttery, creamy mouthfeel in a kit:
Don't use MLF. * Instead: Look for kits that include oak chips or staves. Oak provides the structure and vanilla/toasted notes that people often associate with MLF wines without the risk of ruining the batch.
Pro-Tip: Save the MLF for when you move up to pressing fresh grapes or using high-quality frozen must, where the Malic acid levels are high enough to justify the process!