MLF stands for Malolactic Fermentation. This is a process in which Malolactic bacteria convert malic acid into lactic acid. This conversion of acid creates a smoother mouthfeel in the finished wine. Think about the difference in an apple (malic acid) compared to drinking milk (lactic acid). Even though the word fermentation is in the name, this process technically is not a fermentation at all. Rather, bacteria that is already present in the wine, or added by the winemaker, transforms the malic acid into lactic acid.
Though not all wines undergo MLF, it is safe to assume most red wine undergoes this process. One of the main white varietals that winemakers let go through MLF is Chardonnay. Think of the more buttery/oaky style Chardonnays you have drank in the past - those are the ones that typically go through MLF. If Chardonnay or any other type of white wine for that matter goes through MLF, it is a total stylistic choice of the winemaker depending on what they want the final product to taste like. It is common practice that red wine undergoes MLF because it allows the wine to be smoother as well as keeps the wine more stable for long term storage and aging.
Our PostHarvest Chardonnay as well as Sauvignon Blanc did not go through malolactic fermentation. This was a stylistic choice to let the fruit forward notes and minerality shine through especially with the Chardonnay. On the other hand, we did have our Pinot Noir go through MLF as traditionally done.
Next time you’re trying a wine (specifically a Chardonnay), give your tastebuds a little test... Try to figure out if it has been through malolactic fermentation by determining if the acid is sharper or not as noticeable and take note of what you like better. Cheers!