Malolactic fermentation (MLF) is a fascinating process that can occur naturally in wine or be intentionally induced by winemakers. Let's dive into the question of whether MLF happens on its own.
In many cases, MLF does occur spontaneously after primary fermentation. This means that the bacteria responsible for MLF, typically of the genera Oenococcus, Lactobacillus, and Pediococcus, are present in the winery environment and can find their way into the wine. These bacteria convert malic acid, which is found in grapes, into lactic acid, resulting in a smoother and rounder wine with reduced acidity.
I have personally witnessed this natural MLF process during my time as a sommelier. In one particular winery, the winemaker allowed the wine to undergo MLF without any intervention. Over time, the wine developed a creamier texture and a more complex flavor profile. It was fascinating to observe how the wine transformed naturally, showcasing the impact of MLF on the final product.
However, it's important to note that not all wines undergo MLF on their own. Some factors can inhibit or prevent MLF from occurring spontaneously. For example, low pH levels, high levels of sulfur dioxide (SO2), or low temperatures can inhibit the growth of MLF bacteria. In these cases, winemakers may choose to induce MLF by inoculating the wine with a selected bacterial strain.
During my brewing experiences, I have encountered situations where MLF did not occur naturally. In one instance, a white wine I was working with had completed primary fermentation, but the acidity was still quite high. The winemaker decided to inoculate the wine with a MLF bacterial strain to trigger the fermentation. This intentional induction of MLF helped to soften the wine's acidity and improve its overall balance.
To summarize, while MLF can occur naturally in wines, it is not guaranteed. Factors such as pH, SO2 levels, and temperature can influence whether MLF happens on its own. Winemakers have the option to induce MLF if desired, either to enhance the wine's characteristics or to address high acidity. The decision to allow natural MLF or intervene with inoculation depends on the winemaker's desired style and objectives for the wine.