The short answer
What is potassium sorbate? It is the potassium salt of sorbic acid, C6H7KO2, a white, very water-soluble powder or granule that stops moulds and yeasts from growing. As a food additive it is E202, and it is often sold simply as “K-sorbate”. It is used in cheese, baked goods, dried fruit, drinks, sauces, wine, cider, mead, cosmetics and pharmaceuticals.
Potassium sorbate does not kill microbes outright. It slows them down so that they cannot multiply, and it works best in acidic products. That is why it is a preservative and a wine stabilizer, but not a sterilant.
Potassium sorbate formula and identifiers
| Item | Value |
|---|---|
| Molecular formula | C6H7KO2 (CH3CH=CH–CH=CH–COOK) |
| Chemical name | Potassium (2E,4E)-hexa-2,4-dienoate |
| Molar mass | 150.22 g/mol |
| CAS number | 24634-61-5 |
| Food additive number | E202 (INS 202) |
| Parent acid | Sorbic acid, C6H8O2, CAS 110-44-1, E200 |
| Sorbic acid content | 74.6% (theoretical) |
| HS code (6-digit) | 2916.19 |
| Synonyms | K-sorbate, sorbic acid potassium salt, “kalium sorbate” (kalium is Latin for potassium) |
The molar mass comes from six carbon at 12.011, seven hydrogen at 1.008, one potassium at 39.098 and two oxygen at 15.999: 72.07 + 7.06 + 39.10 + 32.00 = 150.22 g/mol. Sorbic acid has a molar mass of 112.13 g/mol, so 112.13 ÷ 150.22 means each gram of potassium sorbate supplies about 0.746 g of sorbic acid. Legal limits are usually written as sorbic acid, so keep this figure handy when you dose. Unlike sorbic acid, which dissolves poorly in cold water, the potassium salt dissolves readily, and that is the main reason it is the form most food and drink makers buy.
How potassium sorbate works
In solution, potassium sorbate releases sorbate ions, which are in balance with undissociated sorbic acid. The undissociated acid is the active form. It passes into mould and yeast cells and interferes with their enzymes. Sorbic acid has a pKa of about 4.76, so the lower the pH, the more of it is in the active form:
- Below about pH 4.5 (wine, cider, soft drinks, pickles), it is highly effective at low doses.
- Up to about pH 6 to 6.5 (cheese, some baked goods), it still works, but higher doses are needed.
- Against bacteria it is weaker and more selective, so it is normally one part of a preservation system, not the whole of it.
Potassium sorbate in wine, cider and mead
Home and commercial winemakers use potassium sorbate as a wine stabilizer when a finished wine, cider or mead is to be back-sweetened. Without it, any yeast left in the wine can ferment the new sugar in the bottle, giving fizz, haze or burst bottles.
- Add it after fermentation has finished and the wine has cleared and been racked off the lees. Sorbate stops yeast from multiplying; it will not reliably halt an active fermentation.
- Always pair it with sulphite. Add potassium metabisulfite at the same time. The sulphite protects against bacteria and oxidation, and sorbate on its own leaves the wine exposed.
- Avoid it after malolactic fermentation. Lactic acid bacteria can convert sorbic acid into compounds with a strong “geranium” off-odour. Do not use sorbate in wines that have gone, or may go, through malolactic fermentation.
- Use it in sweet styles only. A fully dry wine that will not be sweetened does not need it.
How much potassium sorbate per gallon
Dose by the sorbic acid you want in the wine. Using the 74.6% figure:
Grams of potassium sorbate = target sorbic acid (mg/L) × volume (litres) ÷ 746
| Batch size | For 150 mg/L sorbic acid | For 200 mg/L sorbic acid |
|---|---|---|
| 1 US gallon (3.785 L) | 0.76 g | 1.01 g |
| 5 US gallons (18.9 L) | 3.8 g | 5.1 g |
| 100 litres | 20 g | 27 g |
| 1,000 litres | 201 g | 268 g |
The common home-winemaking rule of about half a teaspoon per gallon falls in the same range, but a teaspoon of granules and a teaspoon of fine powder do not weigh the same, so weigh it if you can. Dissolve the sorbate in a little water or wine and stir it in evenly. Mead and cider are dosed the same way.
Limits apply to finished wine. The EU allows up to 200 mg/L of sorbic acid, and the US TTB allows up to 300 mg/L. Other markets set their own figures. Many tasters notice sorbate above roughly 200 mg/L, so stay at the lowest dose that does the job.
Other uses of potassium sorbate
- Dairy: cheese, cheese coatings, spreads and some yoghurt-based products, against moulds and yeasts.
- Bakery: cakes, fillings, tortillas and flatbreads, often added to the surface or filling rather than the dough, because it can slow down baker’s yeast.
- Fruit and vegetables: dried fruit (prunes labelled “non-sorbate” are simply ones made without it), jams, pickles, olives and fruit preparations.
- Beverages: soft drinks, juice drinks and syrups, often together with sodium benzoate.
- Sauces and dressings: mayonnaise, ketchup, salad dressings and other acidic condiments.
- Cosmetics and personal care: creams, lotions and shampoos as a mild preservative. EU cosmetics law limits sorbic acid and its salts to 0.6%, calculated as the acid.
- Pharmaceuticals: as an antimicrobial preservative in oral liquids and topical products, using a pharmacopoeial grade.
- Animal feed: as a preservative where feed regulations allow it.
Potassium sorbate vs sodium benzoate
| Potassium sorbate | Sodium benzoate | |
|---|---|---|
| Formula | C6H7KO2 | C7H5NaO2 |
| Food additive number | E202 | E211 |
| Active acid (pKa) | Sorbic acid (about 4.76) | Benzoic acid (about 4.2) |
| Works best | Up to about pH 6 to 6.5 | Below about pH 4.5 |
| Strongest against | Moulds and yeasts | Yeasts and some bacteria |
| Typical use | Cheese, bakery, wine, cosmetics | Soft drinks, pickles, acidic sauces |
Because their strengths overlap but are not the same, sodium benzoate and potassium sorbate are often used together in drinks and sauces, which lets each be kept at a lower level. If you are reformulating, check the permitted combined limits in your market. We supply both, including food-grade sodium benzoate.
Grades and what to specify
- Food grade (E202): meets food additive specifications such as FCC, JECFA or EU Regulation (EU) No 231/2012, with limits on heavy metals and other impurities. This is the grade for food, drinks and wine. See our potassium sorbate page.
- Pharmaceutical grade: meets a pharmacopoeial monograph such as USP-NF, Ph. Eur. or BP. See potassium sorbate pharma grade.
- Cosmetic grade: for personal care formulations. See cosmetic potassium sorbate.
Potassium sorbate is sold as granules (dust-free and free-flowing, preferred for weighing by hand), powder (dissolves fastest and blends well with dry mixes) and sometimes as extruded pellets. In the order, state the specification or monograph, the assay (food and pharmacopoeial specifications typically require 98.0 to 101.0% on the dried basis), the loss on drying, the limits for heavy metals and aldehydes, the physical form and particle size, and the packing.
Is potassium sorbate safe? Handling and storage
- Regulatory status: potassium sorbate is an authorised food additive (E202) in the EU, where EFSA has re-evaluated sorbates and set an acceptable daily intake. In the United States it is generally recognised as safe (GRAS) under 21 CFR 182.3640.
- The “banned in Europe” myth: the EU did not ban potassium sorbate. It removed calcium sorbate (E203) in 2018 because the data needed to re-evaluate it were not supplied.
- Sensitivity: a small number of people get skin irritation from sorbates in cosmetics. Reactions to food use are uncommon.
- Handling the bulk powder: classification varies between suppliers, and several safety data sheets list it as a skin and eye irritant. Wear gloves and eye protection when weighing, and avoid raising dust. It is not regulated as dangerous goods for transport.
- Storage: keep it in tightly closed containers in a cool, dry place away from light and oxidising agents. Sorbates slowly oxidise and discolour in air, so open stock should be used within a reasonable time and resealed after each use.
Follow the safety data sheet (SDS) supplied with the batch for classification, first aid and transport details.
Enquire with Scapex Exports
Scapex Exports is an exporter and supplier of industrial, food and fine chemicals from India. For potassium sorbate, see our food-grade, pharma-grade and cosmetic-grade pages. Related products include food-grade potassium metabisulphite and sodium benzoate. We supply to an agreed specification, with a certificate of analysis and a 16-section GHS MSDS for every batch, a certificate of origin and full export documentation. Our sodium metabisulphite guide covers the other common food and wine sulphite.
Tell us the grade, the specification, granules or powder, the quantity, the packing and the destination port, and we will reply with a quotation.
Frequently asked questions
What is potassium sorbate?
Potassium sorbate is the potassium salt of sorbic acid, C6H7KO2 (CAS 24634-61-5, food additive E202). It is a white, water-soluble powder or granule used to stop moulds and yeasts growing in food, wine, cider, mead, cosmetics and pharmaceuticals.
Is potassium sorbate bad for you?
At permitted levels potassium sorbate is an approved food additive: it is E202 in the EU, where EFSA has re-evaluated it, and generally recognised as safe (GRAS) in the United States. A small number of people react to it, mostly as skin irritation from cosmetics.
Why is potassium sorbate banned in Europe?
It is not. Potassium sorbate (E202) and sorbic acid (E200) are authorised food additives in the EU. The sorbate that was removed from the EU list in 2018 was calcium sorbate (E203), because the safety data needed for its re-evaluation were not supplied.
How much potassium sorbate per gallon of wine or mead?
Potassium sorbate is about 74.6% sorbic acid. To reach 200 mg/L of sorbic acid in one US gallon (3.785 L) you need about 1.0 g of potassium sorbate. The common home rule of half a teaspoon per gallon is in the same range. Always add it together with sulphite.
Does potassium sorbate stop fermentation?
No. It does not kill an active yeast population. It stops yeast from multiplying, so it is added after fermentation has finished and the wine has cleared, together with potassium metabisulfite, to prevent fermentation restarting after sweetening.
Is potassium sorbate natural?
Sorbic acid was first isolated from rowan berries, but the potassium sorbate sold today is made synthetically. It is chemically the same compound, and it contains no gluten.
What is the difference between potassium sorbate and sodium benzoate?
Both are preservatives that work best in acidic products. Potassium sorbate mainly controls moulds and yeasts and still works up to about pH 6, while sodium benzoate needs a more acidic product, below about pH 4.5. Drinks often use the two together.
Sources: PubChem compound records for potassium sorbate (CAS 24634-61-5) and sorbic acid (CAS 110-44-1); molar masses calculated from IUPAC standard atomic weights; EU food additive list (E200, E202, Regulation (EC) No 1333/2008) and Commission Regulation (EU) 2018/98 (removal of E203); EU wine rules, Commission Delegated Regulation (EU) 2019/934; US eCFR, 21 CFR 182.3640 and 27 CFR 24.246; EU Cosmetics Regulation (EC) No 1223/2009, Annex V; supplier safety data sheets for potassium sorbate.