For those of you who dont know this there are more reasons for using sorbate then just to make sure your wine doesnt start fermenting again in the bottle after sweetening a wine. There are reasons to use it even if you havent sweeten your wine. Here is an article copied from Wikipedia for you to help understand this a little better. I know Masta posted something like this quite awhile ago but sometimes stuff gets forgotton and there are many new winemakers who could benefit from this.
Potassium sorbate is the potassium salt of sorbic acid. Its primary use is as a food preservative (E number 202). Potassium sorbate is effective in a variety of applications including food, wine, and personal care.
(1) Chemistry
The molecular formula of potassium sorbate is C6H7O2K and its systematic name is potassium (E,E)-hexa-2,4-dienoate. Its has a molecular weight of 150.22 g/mol. It is very soluble in water (58.2% at 20 °C). It is prepared by the reaction of sorbic acid with potassium hydroxide.
(2) Use
Potassium sorbate is used to inhibit molds and yeasts in many foods, such as cheese, wine, yogurt, dried meats, apple cider and baked goods. It can also be found in the ingredients list of many dried fruit products. In addition, herbal dietary supplement products generally contain potassium sorbate, which acts to prevent mold and microbes and to increase shelf life, and is used in quantities at which there are no known adverse health effects.[citation needed] Labeling of this preservative reads as "potassium sorbate" on the ingredient statement. Also, it is used in many personal care products to inhibit the development of microorganisms for shelf stability. Some manufacturers are using this preservative as a replacement for parabens.
Also known affectionately as "wine stabilizer", potassium sorbate produces sorbic acid when added to wine. It serves two purposes. When active fermentation has ceased and the wine is racked for the final time after clearing, potassium sorbate will render any surviving yeast incapable of multiplying. Yeast living at that moment can continue fermenting any residual sugar into CO2 and alcohol, but when they die no new yeast will be present to cause future fermentation. When a wine is sweetened before bottling, potassium sorbate is used to prevent refermentation when used in conjunction with potassium metabisulfite. It is primarily used with sweet wines, sparkling wines, and some hard ciders but may be added to table wines which exhibit difficulty in maintaining clarity after fining.
