Do you like your Chardonnay on the buttery side? Well, here’s a little trivia for you: The substance that makes microwave popcorn buttery is the same thing that makes your Chardonnay buttery. It’s called diacetyl.
But, while the popcorn factories need to add the diacetyl, winemakers can use a special technique called malolactic fermentation. Sometimes it’s called the second fermentation because normally the winemaker will hold off on this technique until the alcoholic fermentation is done.
Here’s how it goes:
It takes the winemaker 3 weeks or so to make a barrel of Chardonnay. Then he adds lactic acid bacteria to the wine, which sets off the malolactic fermentation. Actually, it’s a conversion and we call it ML for short.
ML converts the tart malic acid, the green apple acid, to the softer lactic acid, the milk acid. This reduces the total acidity so the wine feels softer on your palate. Diacetyl is a byproduct. So, this conversion makes the wine smell buttery, makes the texture a bit more viscous and oily and seems to have a rounding effect.
It doesn’t have to be an all or nothing proposition. If the winemaker made 20 barrels of Chardonnay and put them all through ML that would be some very buttery wine that might taste kind of flat because of the lost acidity. It depends on how high the acid was when he started and how much of it was malic acid (tartaric is the main grape acid).If he wants butter undertones he might put 3 or 4 barrels through ML and blend that with the rest of the wine.
Of course, there’s no law that says he has to do ML at all. If he wants to produce a fruity, crisp style he may choose to avoid the ML entirely. Isn’t it great that we have all this variety available to us?So, the winemaker’s thinking about the level of acidity and how rich and buttery he wants the wine to be as he contemplates putting the wine through ML.
And, the next time a barista serves you a glass of Chardonnay and says it’s 40% ML you’ll know that 8 of those twenty barrels went through ML and that the diacetyl will be fairly noticeable. Just right for someone who likes her Chardonnay on the buttery side.