Is Potassium Metabisulfite (E224) Vegan?

Also known as: Potassium pyrosulfite, Campden tablets, K2S2O5, Potassium metabisulphite

Vegan

Potassium metabisulfite is vegan. Producers absorb sulfur dioxide into a potassium base and crystallize the salt, using mineral inputs only. Winemakers and home brewers know it as Campden tablets.

Last checked How we decide
Same substance, other rolePotassium metabisulfite in winemakingIts role as a sterilant and antioxidant during production

Ingredient Data

Vegan Status

Vegan

E-Number

E224

Also Known As

Potassium pyrosulfite; Campden tablets; K2S2O5; Potassium metabisulphite

Source

A mineral sulfite salt. Sulfur is burned to sulfur dioxide, and the gas is absorbed into a potassium carbonate or potassium hydroxide solution, then crystallized. Dissolving the crystals releases sulfur dioxide again, which does the antimicrobial and antioxidant work.

Commonly Found In

Wine, cider, perry, mead, and beer, dried fruit, fruit juices and concentrates, vinegar, sauces, and some baked goods. Sold to home brewers and winemakers as Campden tablets or sterilizing powder.

Vegan Alternative

No substitute needed. E224 is vegan.

Additional Notes

Winemakers prefer the potassium form over the sodium one because it does not add sodium to the wine and because potassium is already present in grape juice. Sulfites must be declared as an allergen above 10 mg per liter expressed as sulfur dioxide, which covers nearly all wine. Sulfites are also produced naturally during fermentation, so a wine with no additions is rarely sulfite-free.

In depth

The Winemaker's Salt

Sulfur dioxide has been used in winemaking since the Romans burned sulfur candles inside barrels. The modern version is a measured dose of potassium metabisulfite, added at crush, after fermentation, and again before bottling. Production is mineral chemistry. Burning elemental sulfur, recovered from oil and gas processing or mined, gives sulfur dioxide; absorbing that gas into potassium hydroxide or carbonate solution and crystallizing the product gives the powder.

Wine, cider, and mead makers choose potassium over sodium because sodium alters the taste and the mineral profile, while potassium sits naturally in grape juice at far higher levels. Home brewers buy the same compound compressed into Campden tablets, each dosed for a gallon or five liters. Nothing in that supply chain is animal-derived.

Why Sulfites Do Not Settle the Wine Question

Readers frequently arrive at sulfites while trying to work out whether a wine is vegan, and the two questions do not overlap. Sulfites are mineral salts and are vegan. What decides a wine's status is fining, the clarification step that strips haze and harsh tannin before bottling. Traditional fining agents are isinglass from fish swim bladders, gelatin from animal collagen, casein from milk, and egg white.

All are filtered out before sale, and EU labeling does not require them to be declared unless allergen residues remain, which is why the bottle rarely tells you. Plant-based and mineral alternatives now cover most needs: bentonite clay, pea protein, potato protein, and activated carbon. A vegan certification mark on the label is the reliable signal, and "contains sulfites" carries no information either way.

Organic Wine and Low-Sulfite Labels

EU organic wine rules allow sulfites at lower maximum levels than conventional wine, so an organic label implies less added sulfur dioxide without implying none. Natural wine producers often push lower still, and some bottle with no addition at all. Zero-sulfite wine is close to impossible, because yeast produce sulfites during fermentation.

A wine with no addition typically still carries 10 to 20 mg per liter, which is why the allergen declaration often stays on the label. Low-sulfite wines trade stability for purity. They are more prone to oxidation and refermentation, need cold storage, and vary more from bottle to bottle. None of that changes the vegan answer, which still depends on how the wine was fined.

Frequently asked questions

Is E224 vegan?

Yes. Potassium metabisulfite is made from burned sulfur absorbed into a potassium base, using mineral raw materials only. No animal-derived material is involved.

Are Campden tablets vegan?

Yes. Campden tablets are compressed potassium metabisulfite, sometimes sodium metabisulfite, sold in pre-measured doses for home brewing and winemaking. Both salts are mineral.

Does sulfite-free wine exist?

Not really. Yeast produce sulfites during fermentation, so even a wine with nothing added usually carries 10 to 20 mg per liter and still needs the allergen declaration. Producers can only minimize sulfites, not eliminate them.

Does contains sulfites mean the wine is not vegan?

No. Sulfites are mineral salts and are vegan. A wine's status depends on the fining agents used to clarify it, which may be isinglass, gelatin, casein, or egg white, and those are almost never listed on the label.

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