not a natural acid found in grapes but intentionally added as a preservative in wines. Typically, you'll see 150-200 ppm (taste threshhold typically around 135 ppm, although it may be as low as 50ppm) sorbic acid used to stabilize wine concentrates and sweet wines. It fights certain microbial infections, and will stop wine yeast from working on a sweet wine, if racking, 50 ppm SO2 or 0.5 micron filtration don't work. Use sorbic acid as a last resort, because it decreases wine quality, usually by producing off flavors and odors (like butter or oxidized fat). It doesn't kill yeasts, but only prevents them from multiplying, and thus sometimes fails to prevent a slow fermentation in the bottle if yeasts have not been reduced enough. Sorbic acid also reacts with and reduces free SO2, so you have to keep your SO2 levels up if you're going to use sorbic acid. Best advice: Avoid addition of Sorbic Acid.

additive widely used in the food and drink industries to stun yeasts and moulds. Sometimes used for inexpensive sweet wines, it smells of crushed geranium leaves, excessively to a small proportion of particularly sensitive humans.

Sorbic acid is a yeast growth inhibitor whose sole function is to prevent yeast growth. It is usually added as the more soluble potassium sorbate which contains approximately 75% sorbic acid. The effectiveness of sorbic acid can be greatly reduced when a large amount of yeast cells a present, so it should be added at the final racking stage or ideally after filtering. Low alcohol and high pH levels can also reduce its effectiveness and should be used in conjunction with sulphur dioxide as it has no antioxidant or anti bacterial properties.

Natural preservative made from berries of the mountain ash tree. A fungicidal agent which also acts as a humectant.

Acid used as anti-septic and anti-oxidizing agent. Particularly used in sweet white wines with the purpose of avoiding the risks of secondary refermentation.

a water-soluble acid and preservative.