Malolactic Fermentation on Wine Kits?

Malolactic Fermentation on Wine Kits?

Wine kits are great for experimenting. Whether you want to swap out the yeast, try a split fermentation with multiple strains, or use different types of oak kits are the most economical wine making medium to experiment on. Malolactic fermentation, however, is not something that should be experimented with on most wine kits. In fact unless your kit came with malolactic bacteria I suggest steering clear of MLF altogether. Why? What Malolcactic Fermentation Does to Kit Wines Lactic acid bacteria, such as the strain of lactobacillus shown here, consumes malic acid and converts it into lactic acid. By comparison lactic acid is weaker than malic acid which is exactly why you would perform malolactic fermentation in the first place. An overly acidic wine can be put through malolactic fermentation to reduce the total acidity. Most wine kits, however, have been tartrate balanced at the time of manufacture. This process increases the amount of malic acid in the wine making juice. By performing a malolactic fermentation you will not only be reducing an already balanced acidity, you will also be converting the bulk of the acid present into lactic acid. This can drastically lower your acidity and raise the pH, sometimes as high as 3.8. The result will be a flat and uneventful wine. Lactic acid also has a buttery flavor to it that can complement some wine is moderation. Creating a wine that has a majority of lactic acid in it may come out tasting really buttery. Malolactic Bacteria and Sorbate Another measure that kit manufacturers take to prolong the shelf life of their product is adding sorbate to the unfermented juice. Additionally most kits also call for sorbate to be added after primary fermentation to prevent further fermentation once the wine has been bottled. It turns out that malolactic bacteria interacts with sorbate to produce a chemical known has hexadiene. The presence of this in wine causes rotting geranium odors to form. This is both disgusting and cannot be fixed once it sets in. Some wine making sites suggest that you can successfully perform malolactic fermentation on wine kits provided that you delay the addition of sorbate until after malolactic fermentation has completed. This seems risky though given that there may be some sorbate already in there and because there may also be an abundance of malic acid. This is probably something that will vary from one kit manufacturer to another. For more information on malolactic fermentation check out What is Malolactic Fermentation?. Photograph used under Creative Commons licence. Photgraph by:...

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What is Malolactic Fermentation?

What is Malolactic Fermentation?

Malolactic fermentation is often associated with red wines and some Chardonnays. Specifically “buttery” Chardonnay. But what is it? As the name implies it is a form of fermentation. Unlike a yeast fermentation, however, during malolactic fermentation no alcohol is produced. Instead malic acid is converted into lactic acid by lactic acid bacteria. Clever name I know. How Malolactic Fermentation Works Just like yeast, there are lactic acid bacteria all around us and the grapes that we make into wine. Not all species, however, will produce a drinkable wine. There are only about four species we trust. Thus to initiate a malolactic fermentation it is best to purchase a lactic acid bacteria specifically suited for the job. These can be found at many winemaking supply stores. After primary fermentation is complete you inoculate your wine with the bacteria. It is important to prevent oxygen from coming into contact with your wine during this process as the bacteria only produce desirable results when they work anaerobically (without oxygen). In simple terms the bacteria consume malic acid and convert it to lactic acid and carbon dioxide. There are a few reasons this is a good idea. Why Should I do a Malolactic Fermentation? Great question. More can be understood if we talk about the chemical process that your wine undergoes. First of all there’s the issue of stability. The presence of malic acid in our wines makes it a breeding ground for good and bad lactic acid bacteria. If you don’t do a malolactic fermentation prior to bottling it could happen later once it’s in the bottle. I once purchased a bottle of wine that underwent a malolactic fermentation after I bought it. The bottle blew out the cork making a holy mess. Not only that, what wine was left over tasted terrible. It was cloudy, bubbly, and lacked any of the flavors we bought it for. The second reason to go through this process is to reduce acidity. Lactic acid is a less potent acid than malic acid. In general the acidity of a wine may be reduced by 0.1-0.3%. This may not sound like much but it is enough to taste a difference. Speaking of taste, this is the third major reason for doing a malolactic fermentation. Malic acid is said to have a tart taste to it, similar to the peel of a green apple. Lactic acid, on the other hand has a buttery or milky flavor to it. Lactic acid is also present in milk and other dairy products. In fact lactic acid is often referred to as “milk acid”. If you’ve ever heard a Chardonnay described as buttery, it has likely undergone malolactic fermentation. Like a yeast fermentation a malolactic fermentation can get stuck. This can be caused by fermentation temperatures that are too low. Also, too much sulfur dioxide in your wine can prevent them from working their magic. There are chromatography tests you can do to see if fermentation has completed. We’ll get into exactly how to do all of this in a future post. The important things to know about malolactic fermentation is that it is...

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