Ever have a cork blow out of a bottle or wine that was carbonated? If you have, you were not happy about it and either scenario can and should be avoided. The solution is an inexpensive and simple fix that will ensure it never happens again, or at all. Say hello to potassium sorbate.

Potassium sorbate is an intrinsic food-grade additive used in winemaking as both a stabilizer and preservative. It is a white, odorless, and tasteless powder that is soluble in water and if used properly it will not affect the flavor of your wine. It is a simple potassium salt of sorbic acid, which is a naturally occurring fatty acid found in some fruits and vegetables.

The most important function of Potassium sorbate is that it prevents yeast from reproducing. Even wines that are fermented dry have small amounts of residual sugar. If your wine is bottled and subject to even small temperature increases, it can cause yeast organisms to reactivate. If this happens, they will process those remaining sugars and produce carbon dioxide gas. If your wine is already in the bottle, where will that gas go? If your wine is dry, about the worst that will happen is that it will cause carbonation, but nobody wants to drink a fizzy dry Cabernet Sauvignon. However, considering what else can happen, carbonation is the least of your potential risks.

If your wine is not fermented dry and your ABV is below the threshold of maximum alcohol, you can have a real issue on your hands without potassium sorbate. In the case of dry wines, most of the yeast organisms die off on their own as sugars are depleted and the alcohol levels near their tolerance threshold. More sugar and low alcohol mean a lot of yeast organisms are alive and still active. Once the wine is bottled, active yeast will continue processing sugar. Pressure will build behind the cork. If it is not enough to blow it out, it will erupt like a shaken soda can when you open it. If enough pressure builds to blow out the cork, imagine it happening to thirty bottles at once. All it takes is a few degrees increase into the range of fermentation, which is essentially room temperature, and your wine rack can turn into a shooting gallery. If you added sugar to back sweeten, you made matters even worse.

Potassium sorbate will assist you in avoiding these frightful scenarios. So how do you use it?

Potassium sorbate should be added to the wine a few weeks before bottling or back sweetening. The recommended dose is 1/2 a teaspoon per gallon of wine. Some sources say you can add it sooner but that is not advisable. Even when you think fermentation is over, it isn’t. Those last increments of sugar take weeks to process because at that stage, the yeast process sugar very slowly. By allowing your wine to have some time in secondary before adding sorbate, you will ensure your yeast population is already as small as possible. Since potassium sorbate does not kill existing yeast, but rather prevents them from reproducing, it is important you add it at the right time, so it thoroughly dissolves into your wine before you back sweeten or bottle.

It is also important that you use it in conjunction with sulfites. Though potassium sorbate has no taste, using it without sulfites can cause the production of ethyl acetate which has a banana-like flavor. The sulfites bond with these compounds and prevent them from forming. You don’t need much either. An 1/8 of a teaspoon of sulfites is sufficient for a six-gallon batch when adding potassium sorbate.

There are also some who argue that potassium sorbate can be used to stop fermentation. While this is technically true, it is also not recommended. The more sugar you have, the more sorbate you need. Too much potassium sorbate can cause a soapy and bitter flavor. It can also cloud your wine. Best practice for sweet and semi-sweet wines is to adjust your sugars prior to fermentation for your desired ABV. Allow it to ferment dry, add potassium sorbate and then back sweeten.

In conclusion, potassium sorbate is intrinsic to winemaking. You need to use it with sweet and semi-sweet wines, and you should even use it in dry wines. You may think your wine fermented totally dry, but what if it didn’t? You might have a cool cellar for storage but what about bottles you give away? Can you control how they will store it? You can’t. Do you want a friend or colleague to open a bottle of your dry red and taste carbonation? Worse yet, do you want it to erupt on their kitchen table? You don’t. Potassium sorbate is a safe and tasteless additive that will stabilize your wine, protect it from the dangers of temperature fluctuation and save you from corks shooting at your head while you are watching TV. Cheers!

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