Potassium sorbate

Potassium sorbate is the potassium salt of sorbic acid. Food makers know it as E202, a preservative that slows the growth of mould and yeast. It's sold as white granules or powder that dissolve easily in water.

• Formula: C6H7KO2
• CAS number: 24634-61-5
• Molar mass: about 150.2 g/mol
• Solubility: very soluble in water, about 58 g per 100 mL at 20 °C; also soluble in propylene glycol and ethanol
• Melting point: decomposes at about 270 °C

In water it turns partly into sorbic acid, and that's the form that does the work. So the more acidic the product, the better it performs. Above about pH 6.5 it does very little.

Azlok has two potassium sorbate listings:

For anything you will eat or drink, buy only the listing marked food grade and use it within FSSAI limits for your product category. The second listing doesn't state a grade, so treat it as a general or cosmetic-use material unless the product page says otherwise. Check today's price per kg.

• Food: cheese, baked goods, jams, fruit fillings, sauces, pickles, syrups and soft drinks, to slow mould and yeast spoilage.
• Wine and fruit wines: added after fermentation, usually with sulphite, to stop leftover yeast restarting fermentation when the wine is sweetened.
• Cosmetics and toiletries: part of the preservative system in creams, lotions, shampoos and gels, often as an alternative to parabens.
• Home and small-batch food makers: for jams, squashes and sauces sold locally, where a licensed recipe allows it.

• Dissolve first. Make a small solution in clean water and stir it in, rather than sprinkling dry powder into a thick product.
• Keep it small. Food uses typically fall between 0.025% and 0.1% of the product (about 0.25 to 1 g per kg). The exact legal maximum depends on the food category, so check the FSSAI food additive rules for yours.
• Watch the pH. It works best in acidic products. In a low-acid sauce or cream it gives poor protection.
• Cosmetics: it's typically used at about 0.1 to 0.3%, at pH below 6, and usually paired with another preservative, because on its own it doesn't cover bacteria well.
• Wine: add it only after fermentation has finished and the wine has cleared. It won't stop an active fermentation.

It is a preservative aid, not a substitute for clean equipment, proper cooking, sealed jars and cold storage.

• The powder can irritate eyes and the nose if it gets dusty. Weigh it gently and wash your hands after.
• Use a separate scoop and spoon for food-grade stock. Don't mix it with lab or cleaning chemicals.
• Store in a tightly closed container in a cool, dry place away from sunlight. It slowly breaks down in light and air, and can turn yellowish.
• Keep away from strong oxidisers and strong acids.
• Keep away from children. Dosing is in grams per kg, so a measuring spoon or digital scale avoids overdoing it.
• Small spills can be swept up and thrown in normal waste.

If you are adding it to food or drinks, pick the food grade 150 g pack. At food doses, 150 g goes a long way for a home kitchen or a small jam or pickle business. If you make cosmetics, either listing can work, but ask for the certificate of analysis if your buyers or regulators need it.

Food units and cosmetic manufacturers using it every week can save by buying in larger lots. For 25 kg or more, use the bulk inquiry form and mention the grade and paperwork you need.