Potassium Sorbate: What It Is & How to Use It in Wine Making
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Potassium sorbate is the chemical behind "wine stabiliser" and "fermentation stopper". It's what lets you sweeten a finished wine, cider or mead without it starting to ferment again in the bottle. Used correctly it's simple and very effective, but it's also widely misunderstood, so here's what it does and doesn't do.
What Is Potassium Sorbate?
Potassium sorbate (E202) is a food-grade preservative that stops yeasts and moulds from multiplying. In home brewing, its job is to stop any yeast left in a finished wine from reproducing and fermenting new sugar.
The key point: it doesn't kill yeast. It stops yeast reproducing. That means it can't stop a fermentation that's already going, and it has to be used on a wine that's finished and clear.
When to Use It
- Before sweetening a dry wine, cider or mead ("back-sweetening")
- Before bottling any wine where you want extra insurance against refermentation
When not to use it
- During an active fermentation. It won't stop it. Wait until fermentation has finished.
- In beer, or anything you want to carbonate in the bottle. It will stop the priming sugar fermenting, so you'll get flat bottles.
- In wines going through malolactic fermentation. The bacteria involved can react with sorbate to produce an unpleasant geranium-like smell.
How to Stabilise and Sweeten a Wine
- Make sure fermentation has completely finished: the same hydrometer reading two or three days in a row.
- Rack the wine off its sediment, and clear it with finings if needed.
- Add potassium sorbate at the dose on the pack (our BrewCo Potassium Sorbate is 1g, about half a teaspoon, per gallon), together with one crushed Campden tablet per gallon. Stir well.
- Wait a day or two, then sweeten to taste with sugar or wine sweetener, adding a little at a time.
- Bottle.
Why both? Sorbate stops yeast reproducing; the Campden tablet (sodium metabisulphite) protects against oxidation and spoilage bacteria. Together they're the standard way to stabilise a wine. Read more in our sodium metabisulphite guide.
Which Product to Buy
- BrewCo Potassium Sorbate 30g – enough for around 20+ demijohns
- Fermentation Stopper (Wine Stabiliser) – potassium sorbate, sold under its common name
- Handcraft Supplies Wine Stabiliser 25g
Always follow the dose on the pack you're using.
Frequently Asked Questions
What does potassium sorbate do in wine?
It stops any remaining yeast from reproducing, so a finished wine can be sweetened without fermenting again in the bottle.
Will potassium sorbate stop fermentation?
No. It doesn't kill yeast, so it won't stop an active fermentation. Use it only once fermentation has finished.
Is "wine stabiliser" the same as potassium sorbate?
Usually, yes. Most products sold as wine stabiliser or fermentation stopper are potassium sorbate. Check the label.
Can I use potassium sorbate in beer?
Not in beer you want to bottle-condition, as it will stop the priming sugar fermenting and your beer will be flat.
Do I need Campden tablets as well?
Yes, for best results. Sorbate prevents refermentation; Campden tablets protect against oxidation and bacteria.