The flavors in wine come from three things - the grapes, fermentation and aging. We've explored the flavors from the juice of the grape, the flavors from the grape skins, seeds and stems and we've seen that the yeast can affect flavors during fermentation. But, there's another process that affects a wine's flavor and it's often called Malolactic Fermentation.
But, getting right to the point, this is not a fermentation. It's actually a process in which one type of acid in the wine is converted to another type of acid. So, it is more correctly a Malolactic Conversion, not a fermentation.
In this conversion process, a tart acid that naturally forms in wine, malic acid, is converted to lactic acid. While the tart malic acid can yield flavor sensations much like a tart green apple, the lactic acid is much softer and creates a richer mouthfeel that is often called buttery and can make a wine seem velvety smooth.
Most red wines undergo malolactic conversion while only some white wines, notably Chardonnay, undergo malolactic conversion. This process is most often performed shortly after the end of primary fermentation and just prior to the aging process.
And, speaking of the aging process, we'll explore the flavors that are imparted to wines as they age in next week's blog. Until then, Cheers!