Potassium sorbate is an organic acid widely used in the food industry as a preservative. Usually available as a powder in the form of granules, it principle
use is as a yeast inhibitor in wines that contain residual sugar. It should
always be used in conjunction with adequate SO2. The reason is that if fermentatin re-occurs in the wine afer the sorbate has been added, a metabolic by-product called hexadienol will be produced by the yeast. This compound has the odor of rotting geraniums and will ruin the wine, making it undrinkable and a total loss. To make certain that this does not occur it is absolutely necessary to add sufficient SO2, usually 40-50 ppm at the time you are adding the sorbate
Normal dose of sorbate is 1 to 1 1/4 gram per gallon or 2 1/2 teaspoons per 5 gallons.