My diet:

E224 Potassium metabisulfite

E224PreservativesOrigin: Lab-made
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VeganYes
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The salt is halal. The wine it protects is not.

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The short answer
Potassium metabisulfite (E224) is the sulfite in Campden tablets and in many wines. It must be declared at 10 ppm. The potassium is why winemakers pick it over the sodium salt.
Use in moderation

Safe in small amounts; may bother some people or raise blood sugar.

E-numberE224
Comes fromLab-made
What it doesPreservatives
Glycemic index—
Daily limit0.7 mg/kg
Also calledPotassium metabisulfite, Potassium metabisulphite

Rules by country

🇺🇸 US FDAWarning label required
🇪🇺 European UnionWarning label required
🇨🇦 Health CanadaWarning label required
CaliforniaNo extra rules

Potassium metabisulfite is a sulfite, E224, and it sits under the same declaration rule and the same group intake as the other sulfites: labels declare sulfites at 10 ppm or more, and the group acceptable daily intake is 0.7 mg per kilogram as sulfur dioxide. Winemakers choose the potassium salt so they are not also adding sodium. The asthma warning is identical.

How much is too much? (Acceptable Daily Intake)

49 mgper day is the safe upper limit

Based on 0.7 mg per kg of body weight (EFSA / JECFA). A 20 kg (44 lb) child: 14 mg a day.

What is it?

A Campden tablet crushed into juice releases sulfur dioxide, which stuns microbes so a chosen yeast can take over. The same chemistry keeps bottled wine from oxidizing.

Where it comes from: Potassium metabisulfite is the potassium twin of the sodium salt. Campden tablets, which home winemakers dissolve into a must, are this chemical. In liquid it frees sulfur dioxide, which quiets wild yeast and slows oxidation.

Why it’s in food

  • Doses sulfur dioxide in wine and cider
  • Stuns wild yeast before a fermentation
  • Protects juice from browning
  • Avoids the sodium of the sister salt

Often found in

WineCiderHomebrewFruit juiceDried fruitSome pickles

Also listed as: Potassium metabisulfite, Potassium metabisulphite, Potassium disulfite, Potassium pyrosulfite

Health & gut impact

Same sulfite reactionConcern

People who wheeze from sodium metabisulfite react to this salt too. The mineral is different. The sulfur dioxide it releases is not.

Clinical descriptions of sulfite sensitivity

Why potassiumBenefit

A wine dose of the sodium salt would add sodium. The potassium salt delivers the same sulfur dioxide without that sodium.

Winemaking use of Campden tablets

What can I use instead?

Sodium metabisulfite

Ratio: You add sodium instead

Best for: Dried fruit

Sulfur dioxide

Ratio: It is the gas either tablet releases

Best for: The parent preservative

Related

More preservatives:

Benzoic acid E210Benzoic acid (E210) is the parent of sodium benzoate. It keeps acidic foods from molding. It is allowed within a daily limit, and in soft drinks with vitamin C it can form a little benzene.Use in moderationCalcium disodium EDTA (EDTA) E385Calcium disodium EDTA (E385) grabs stray metals so dressings, sodas and canned beans keep their color and flavor. Very little is absorbed, and it's safe in the small amounts allowed.Use in moderationCalcium Propionate E282Calcium propionate (E282) is the mold inhibitor in most packaged bread. It's considered safe, vegan and gluten-free, though a few small studies have raised questions about behavior in children and blood sugar.Use in moderationCalcium sorbate E203Calcium sorbate (E203) is a salt of sorbic acid that stops mold and yeast from growing in bread, cheese and wine. It's a synthetic, vegan and gluten-free preservative with a long safety record.Generally safe

Common questions

Is a Campden tablet this ingredient?

Yes. Campden tablets are potassium metabisulfite.

If I react to sulfites, is the potassium one safer?

No. Both release sulfur dioxide.

Is Potassium metabisulfite safe?

Use in moderation (52/100). Potassium metabisulfite is a sulfite, E224, and it sits under the same declaration rule and the same group intake as the other sulfites: labels declare sulfites at 10 ppm or more, and the group acceptable daily intake is 0.7 mg per kilogram as sulfur dioxide. Winemakers choose the potassium salt so they are not also adding sodium. The asthma warning is identical.

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Scientific sources & regulatory citations
  • EFSA OpenFoodTox: E224
  • Clinical descriptions of sulfite sensitivity
  • Winemaking use of Campden tablets

INS 224 · CAS 16731-55-8