So getting back to what the connection is between wine and buttered popcorn, movie theaters use an imitation butter flavor in their popcorn that contains mostly oil, salt, and diacetyl. The diacetyl gives the imitation butter its butter flavor. This is the same flavor compound found in a buttery California Chardonnay that has gone through malolactic fermentation. Next time you drink a glass of chardonnay pair it with buttered popcorn and you will be amazed how the similar flavors compliment one another! Due to the fact that it consumes the malic acid, all of which is present at the time the grapes are crushed, malolatic conversion can take place at any time during or after the alcoholic fermentation is complete. Winemakers have to be very careful that malolactic fermentation takes place prior to bottling being that the bacteria can continue to reproduce causing the wine to go through yet another process of fermentation in the bottle, which can create a slightly carbonated wine that will eventually spoil. In addition to reducing acidity, the MLF causes positive sensory changes in the wine that are of great importance.

Happy Tasting!
Brian

Have you ever picked up a glass of Chardonnay and smelled a bouquet reminiscent of hot buttered movie popcorn? If so, the aroma that you are detecting is “diacetyl,” a naturally occurring chemical that is one of the sensory bi-products from a bio-chemical process known as malolactic fermentation. Malolactic fermentation, or MLF, is the final or secondary stage of fermentation for most reds and some white wines (mostly chardonnays). This process carried out by lactic-acid bacteria, converts the stronger more astringent malic acids into softer lactic acids like the ones found predominantly in milk. Depending upon the bacteria present, this process can occur naturally, but in commercial wine making, malolactic conversion is typically initiated by an inoculation of the desirable bacteria. This prevents undesirable strains of bacteria from producing off-flavors. Conversely, winemakers can actively prevent this fermentation when it is not desired, to prevent accidental initiation and maintain the more, tart, acidic characteristics in a finished wine.

The wines that go through MLF tend to be less fruity and may have transient “cheesy” off odors, but this is only temporary and with time will allow the wine to develop greater complexity, including the desired buttery flavor, with aging. It is thought this increased complexity is created because of the by-products of the MLF, which include new odor and flavor molecules that enter into all of the chemical reactions that produce the wines’ bouquet during bulk and bottle aging. Because more kinds of favorable chemical reactions take place in a MLF the bouquet of these wines tends to be more complex and overall more interesting. Diacetyl, is an example of one of these new flavor compounds produced by MLF, that at high concentrations in wine gives it a “buttery” smell.