Potassium sorbate (or k-sorbate) is a common additive used in wine kits. It’s usually added in the form of a power after fermentation has completed. But what does it do? What precautions should winemakers be taking when using it?
What does Potassium Sorbate do?
Simply put potassium sorbate is used to prevent spoilage by yeasts and molds in a finished wine. It does this by rendering these micro-organisms unable to reproduce.
It is added to wines that have completed fermentation to prevent spoilage but also to prevent further fermentation of sugars added after fermentation such as when you back sweeten a wine. In the case of wine kits you would add potassium sorbate prior to adding the “f-pack” (grape juice concentrate).
Usually you wouldn’t add potassium sorbate to a dry red wine because the sugars have been completely exhausted and the additive is not needed.
Potassium sorbate should always be used at the same time with potassium metabisulfite. Together they make for a rather inhospitable place for micro organisms.
The sulfites from potassium metabisulfite removes the oxygen from your wine to prevent micro-organisms from getting established while sorbic acid from potassium sorbate renders yeasts and molds unable to reproduce.
Limitations of Potassium Sorbate
While this additive does stabilize wines it does have three distinct limitations. First, it is ineffective against bacteria.
If stray bacteria or lactic acid bacteria were to get in your wine while using only potassium sorbate it would not prevent spoilage or malolactic fermentation (as caused by lactic acid bacteria). The combination of sulfites and sorbate help reduce your risks of this as mentioned before.
The second limitation of potassium sorbate is the length of time it is effective. Once added to wine it stays in the desireable form of sorbic acid only for a short time. Over time it breaks down into ethyl sorbate which can add notes of pineapple or celery to your wine.
The change into ethyl sorbate is not preventable. By using potassium sorbate winemakers are putting a definite shelf life on their wines before they pick up these off flavors.
The third limitation is that it reacts poorly with lactic acid bacteria. According to my research it can produce strong geranium odors which most wine drinkers consider a flaw.
Because of these limitations many wineries do not use potassium sorbate. They opt to stabilize with sulfites only an rely on their ability to properly sanitize everything to prevent spoilage. Interestingly, wines with potassium sorbate may not be classified as organic.
Precautions When Using Potassium Sorbate (Please Read This!)
Despite these limitations kit manufacturers include potassium sorbate in their wine making kits. This is to make sure the wine is as stable as possible even if there were some equipment sanitation lapses.
Potassium sorbate should be stored in a dry area away from heat and light. Storage temperatures should not exceed 100 degrees (F).
Like many additives potassium sorbate is an eye irritant. Should you get any in your eyes flush them with water for 15 minutes and get medical attention.
Lastly, and most importantly, paper or cloths that have absorbed potassium sorbate may spontaneously ignite! So be very careful when cleaning up sorbate spills in your wine making area.
If you do spill and use paper towels or a cloth to sop it up be sure to rinse them thoroughly. I’d also be very reluctant to use this additive in a carpeted area as it would be difficult to remove it without a steam cleaner handy.
Should You Even Use It?
With all the potential flavor issues that potassium sorbate can cause it’s good to ask yourself if you should even use it.
On one hand if you’re new to wine making and you’re using a kit I suggest following the directions completely. Once you have a kit or two under your belt, however, then you can think about leaving it out.
If you’re working with frozen must or fresh fruit that will make a wine that can stand a little aging it’s worth considering leaving it out.
The best thing you can do though is seek experienced advice when it comes to additives. I’ve not yet experimented with leaving it out, however, when I have experimented with it I’ll be sure to report back to you.
If you’re interested you can find out more about potassium sorbate by reading these resources where I did my research for this article.
Potassium Sorbate as a Wine Additive – University of Minnesota Enology Blog
Sorbic Acid As a Preservative in Wine – Jim Gallander
Potassium Sorbate – Wikipedia (where else?)
Photograph from MoreWinemaking.com (affiliate link)