“Smmmmmmoooooooooth like butta.” Have you said something like that during a wine tasting? Well… maybe not exactly that inflection, but you probably catch my drift. That rich, sometimes creamy taste that you get from some wines is called malolactic fermentation and trust me, you probably love it.
Just about all of the red wine you drink goes through malolactic fermentation, as well as some whites (The buttery taste in a Napa Chardonnay? That’s malolactic fermentation for you). It’s a secondary fermentation, which essentially means that it occurs after the initial fermentation in a separate type of vessel. For instance–you’ve fermented your wine in a stainless steel tank and are now moving it over into an oak barrel.
The process of malolactic fermentation reduces the tart, granny smith apple flavors in a wine and instead converts that flavor to something a bit softer on the palette. The malic acids become lactic acids. Often, it can happen naturally in your wine making process–it typically will occur in pretty much anything you’re aging in a barrel. To prevent that process and preserve a more tart wine (think those lighter, brighter summertime whites), it will often be chilled, filtered, and aged in stainless steel or concrete.
In New Zealand, we were lucky enough to see and taste malolactic fermentation in action. At George’s Road Winery, we had the opportunity to taste a recently barreled Syrah that was currently in the process of malolactic fermentation process. The wine was almost effervescent and slightly bubbly, though not nearly as full bodied as the finished product will be. This is a great sign in the wine making process and means that everything is going according to the malolactic fermentation plan. In fact, many winemakers will actually listen for CO2 bubbles bursting in their aging wines!