Bacterial Off-Odors In Wine

Date September 28, 2008

Wine Faults: Bacteria Related Off-Odors In Wine

I don’t remember if I mentioned this in my last post or not, but essentially wine faults are caused by either sulfur compounds or bacteria; and then to pile on top of things there are a handful of other wine nuisances that can’t be categorized. Continuing from, sulfur compounds in wine, let’s learn about bacterial off-odors in wine.

Wine tip: Acidity in wine is usually referred to as astringency.

Lactic Acid In Wine

Remember in grade school when your gym teacher would make you run to hell and back and the next day your muscles would be sore? Turns out, that’s not lactic acid build up at all and neither is this anecdote.

To soften a wine’s astringency from naturally occurring malic acid in grapes and to give a wine some complexity, most notably a ‘buttery’ aroma, a winemaker will use a process called malolactic fermentation. The magic ingredient used to convert the harsh malic acid into its soft, yummy butteriness is lactic acid bacteria. However, if the LAB (for you acronym lovers out there) is not fully removed after the malolactic fermentation process, the wine could take on a sauerkraut stench, not that there’s anything wrong with sauerkraut…

Butyric Acid In Wine

Malolactic fermentation (or malo and at one time, MLF, no not MILF; you hear malo mentioned a lot in the world of wine) can be tricky. If a wine undergoes too much malo, butyric acid will form and give the wine a smell of rancid butter or spoiled Camembert. Yuck. Maybe…

Sorbic Acid

I love ice cream. My new favorite is sorbic acid. It smells of geraniums. It’s an additive used to inhibit yeast in the winemaking process and happens usually when put into the fermentation tank before malolactic fermentation is complete. That’s bad, by the way. If your wine smells of geraniums, that’s not my ice cream.

Ascetic Acid

With normal fermentation, yeast cells in wine naturally produce small amounts of ascetic acid bacteria. An overabundance of ascetic acid in the wine and you’ll get the delightful stink of vinegar, the infamous characteristic of a bad wine. This is called ‘volatile acidity’, or, my girlfriend.

Ethyl Acetate

Just when you think a bad wine can’t get any worse than the stink of vinegar, it does. When a wine goes beyond the astringency of ascetic acid it enters the realm of ‘extreme volatile acidity’. Think of sniffing model airplane glue. Really.

I know what you’re thinking. ‘Phil, this is more than I was looking for out of basic wine knowledge. I just want to learn about wine and know what I’m drinking”. I know, I know. Makes you wonder how wine got such a snobbish reputation with all this boring info. But that’s what you go through if you want to learn about wine. This part of wine basics might be boring or unimportant, but this is the kind of basic wine knowledge that will come up in the world of wine believe it or not, and you’ll thank me down the road when it does.

Next time I’ll go into the last of the wine faults: the uncategorized off-odors in wine. And then we’ll move into some fun wine knowledge: wine grapes. Until then… As they say in checkers, wine me.

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2 Responses to “Bacterial Off-Odors In Wine”

  1. wine glasses said:

    My personal taste in wine varies with the time of year, location and influence of friends. I recently discoverd a fantastic house wine served at a local Italian restaurant that is incredible for the price. One thing that helps any wine is to serve it at the right temperature using the most suitable glasses.

  2. Phil said:

    LOL nice plug, John. Good luck with your website.

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