Comparing E228 - Potassium bisulphite vs E224 - Potassium metabisulphite

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Overview

E228 - Potassium bisulphite

Potassium bisulphite (E228) is a sulphite preservative and antioxidant used most often in wine and some processed foods. It helps prevent browning and spoilage by slowing microbes and oxidation. A small number of people, especially some with asthma, can be sensitive to sulphites.

E224 - Potassium metabisulphite

Potassium metabisulphite (E224) is a sulphite-based preservative and antioxidant used to keep foods and drinks fresh. It releases small amounts of sulphur dioxide that slow browning and help control unwanted microbes in products like wine, fruit products, and some soft drinks.

Synonyms

E228

Potassium bisulphite

Potassium bisulfite

E224

Potassium metabisulphite

Potassium metabisulfite

Functions

antioxidant preservative

Origins

Synthetic

Mineral

Synthetic

Products

Found in 3 products

Found in 466 products

Search rank & volume

#426100 / mo🇺🇸U.S.

#2342.5K / mo🇺🇸U.S.

Awareness score

×2.45

over-aware

×0.79

under-aware

Search volume over time

Interest over time for 3 keywords in U.S. during the last 10 years.

Popular questions

How are bisulfite ions generated in the iodine clock reaction potassium iodate and sodium sulfite?
Bisulfite (HSO3−) comes either directly from dissolving potassium bisulfite (KHSO3 → K+ + HSO3−) or by protonation of sulfite from sodium sulfite in acidic solution (SO3^2− + H+ → HSO3−), which is the pH range used in the iodine clock.
How does sodium bisulfite and potassium iodate react to make iodine reaction with starch?
In acid, iodate (IO3−) oxidizes bisulfite (HSO3−) to sulfate while being reduced to iodide; once bisulfite is depleted, remaining iodate oxidizes iodide to iodine (I2), which then forms the blue complex with starch.
How does sodium bisulfite and potassium iodate react to make iodine reaction with starch equations?
Key steps (acidic medium): IO3− + 3 HSO3− → I− + 3 SO4^2− + 3 H+; then IO3− + 5 I− + 6 H+ → 3 I2 + 3 H2O; and while bisulfite remains, it removes iodine: I2 + HSO3− + H2O → 2 I− + HSO4− + 2 H+.
How long is potassium bisulfite good for?
Stored airtight in a cool, dry place, solid potassium bisulfite is typically usable for about 1–2 years; in solution it loses strength much faster (weeks to a few months) as it oxidizes to sulfate.
How most potassium bisulfite or metab?
Potassium metabisulfite (E224) is more commonly used because it’s more stable, but both it and potassium bisulfite (E228) release SO2; for dosing, KHSO3 is ~53% SO2 by weight and K2S2O5 is ~58%, so slightly less metabisulfite is needed to achieve the same SO2 level.