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?

Potassium sorbate, a stabilizing agent, must be used with care.

Potassium Sorbate Powder (affiliate link)

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.

More Information

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)

  • Adan

    Hey Matt. Thank’s for the read! I was wondering if you’ve experimented with leaving out the potassium sorbate when kit wine-making yet?

    • Hi Adan, glad you enjoyed it! Yes, I have experimented with leaving out the sorbate. If I’m making a dry wine that will not be back sweetened I will not use it.

      If you’re going to back sweeten you can do any one of the following:

      1. Use sorbate to keep the sugar from fermenting
      2. sterile filter the wine (0.45 micron filter pads) to remove the yeast. (no sorbate required)
      3. back sweeten with a non-fermentable sweetener (no sorbate required).

      Non-fermentable sweeteners like stevia may give your wine an artificial sweetener taste so be careful there but that is a method a few Academy members employ.

  • Ross

    I have been making wine with wine kits for over a decade now and I never use potassium sorbate in my process unless it is a fruit wine kit where you have to add juice to it in the clearing stage. i found that when i did use it in my regular wine kits such as California Red and such, it did not turn out quite as nice as if i left it out. Just try it some time. buy two kits the same and make one with and one without. This way you will know for sure what you want to do with the sorbate. So making dry wine leave it out. sweet wines you put it in.

    • Appove

      Matt Williams
      Winemaker’s Academy

    • Hi Ross, thanks for sharing your experience! This is an experiment I need to try sometime so I can have a better grasp on how sorbate affects the flavor of a wine.

      Cheers! -Matt

  • Dan212

    I have only been making kit wine for about one year, and the 3 older men from Italy that showed me how NEVER use potassium sorbate and everyone loves the taste. It has always been a red wine.

    • Hey Dan212! Sorbate does have a bad reputation among many winemakers but it does work for back sweetening if you don’t have a filter. In my mind sorbate is a good tool for beginners to make sweet wines who aren’t ready to spring for a filtration system.

      Were your friends making primarily dry reds? What a great opportunity though to learn from three experience winemakers first hand.

      • Dan212

        Thanks Matt, We made 5 of the same Cab/Merlot kits because after the first one , that’s what everyone said was the best ever. We have bought a Vino Mini filter and like the clarity and it does not change the taste. Plan to try other selections in the future. My wife loves red wine but was never able to drink it because see has migraine problems and always has a problem with red wines, now without sorbate , no problem after 2 glasses. Guessing its the sorbate.

        • Appove

          Matt Williams
          Winemaker’s Academy