4 Types of Preservatives in Wine

In order to preserve wine or have preservatives in wine, you really do not need much but a good hand in winemaking and careful attention to its process. The beautiful thing about nature, especially when it comes to wine, is that wine has plenty of its own preservatives that occur naturally. How long these naturally occurring preservatives allow the wine to age gradually and gracefully depends on their balance.

There are four types of preservatives that are present in wine. To put in simpler terms, they are actually the same components that make up the body of the wine. The most commonly recognized preservative is tannin, followed by acid, residual sugar and alcohol. I will go over each one with you and help you better understand how each one is important to wine preservation.

1. Tannins

Tannins are actually tannic acid, a chemical found in wood, tree bark and the stems, seed and skins of most fruits, in coffee, tea and of course red wine. In young wines, tannins present in wine are not always palatable or enjoyable to experience. They are drying, prevent one salivating and hinder the enjoyment of other elements in wine.

However, as a long-term ingredient, the tannins work as an anti-oxidant ideal for cellaring wine, preventing its early decline. The tannins actually slow down the aging process. Over time, they go through a process called polymerization, where the tannins link and form longer chain molecules and precipitate (fall) from the wine and form a sediment. This is why red wines soften with age as the tannins fall out of it. The rate of which they fall depends on the balance of the following elements of preservation.

2. Acid

Just like the tannic acid work as an anti-oxidant. The antioxidants in wine work very much the same way as they do in our bodies. They attach on to the free radical oxygen molecules so as they do not attach on to anything else causing damage. When wine is bottled, or rather when you bottle your wine at home there are two things you can do. One, if you have a closed top container to syphon your wine from to the bottles you should try and “bubble” the wine with gas. Meaning, with either nitrogen or argon, run a tube of flowing air into the wine so it bubbles. These two gases are heavier than air and will rest on the surface of the wine, reducing the amount of oxygen that will exist in the wine upon bottling. Gas your bottles before they are filled as well.

However, getting back to point, the acid and a balance of it in the wine is crucial to its shelf-life. One of the next preservatives I will go over is alcohol. How does alcohol exist in wine? Well, it is derived via fermentation of sugar. As nature has it, when grapes mature and gain in sugar, which is your potential alcohol, they lose acidity. If you have high alcohol wines with no acidity, or very little of it, the shelf-life or cellaring age will not be very long, as alcohol “cooks” the wine over time in a quicker amount of time.

3. Sugar

I already touched a bit on sugar in describing acid, but I will elaborate. Sugars that naturally exist in grapes, or in the case of some home winemaking, grape concentrate can aid in preserving wine as well. The trick to doing this is not to allow your fermentation to reach 0 degrees Brix. Basically, do not ferment your wine to dryness.

Much like high sugar, glucose and sucrose pastries and treats and things we buy from the store that have a long shelf life due to their high sugar content, wine will also have a longer shelf life with some residual sugars. However, this is not to say to ferment all your wines leaving residual sugar in all of them. For some varietals and styles, the sugar would make the wine out of balance on your palate and might not be good at all. The wines which are most common in leaving some residual sugar are whites or perhaps any fortified wine styles you might try your hand in making, such as Port.

4. Alcohol

Alright, our last preservative for wine! When I speak of alcohol as a preservative for wine, I am not talking about the naturally occurring in wine for fermentation. As mentioned a little bit earlier, the presence of alcohol lacking enough balance of acidity will shorten a wine’s shelf life.

The type of alcohol I am speaking of as a preservative are the alcohols, typically spirits such as Sherry. The style of wines you will add Sherry to or any other spirits are those styles of wines, like Ports. These are wines of grapes that are harvested at very high sugar levels and are not fermented to dryness. A fair amount of sugar is left, sometimes around 30 grams per liter. The fermentation is stopped by adding a spirit. This form of alcohol preserves wine because it is added at high percentages and does not allow the wine to age.

More About Wine Making:

• Shop for Winemaking Supplies
• Winemaking: The Process & Equipment You’ll Need
• Winemaking Preparation: Do You Have Everything You Need?
• Why Sanitation is Important During the Winemaking Process