Updated: Jul 30, 2021
Some people love it, and some, not so much. Frequently, especially Chardonnay will showcase a buttery texture, and even aroma. It is a natural byproduct of a process called malolactic fermentation, a secondary fermentation process that changes malic acid, which is astringent, into lactic acid, which is creamy. The process happens to many red wines, too, although it is harder to perceive in reds. Reds are produced with the skins in contact with the juice, and the color is bled from the skins by macerating the must. When extracting the color the tannic acid present on the skins is imparted into the wine. Malolactic fermentation then allows the creamy texture to offset the tannic structure present in the juice, and bring a harmonious balance to the wine. It is a generally beneficial exercise.
When utilized in white wine production it offers rich, full, creamy body and imparts a specific buttery aroma, far easier to detect amongst the aromatics of white wine. Most frequently this is done in varying degree with Chardonnay production. Malolactic Fermentation (frequently abridged ML) is preventable, and in the production of crisp, light, highly acidic whites it is usually omitted by cooling the fermentation to prevent lactic acid creation. What I enjoy most about ML is the exercise of attempting to ascertain how much, if any was employed during production. A winemaker may elect to allow 30%, 50%, or greater ratios of the blend to generate varying degrees of texture to the batch. Often, after a wine has experienced ML, it is more common for it to rest in an oak barrel for several months, and even a year, or longer before release. This integrates the oak aromas, flavors, colors, and textures into the wine.
Frequently, I will show a comparison/contrast of a Chardonnay unmanipulated with ML versus one that sees intense generation of lactic acid, and a third that splits the difference with a portion of the batch undergoing the secondary fermentation. I would be happy to engineer such a class for you if you want to experience it.