Potassium bisulfite

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Potassium bisulfite
Potassium bisulfite.svg
IUPAC name
Potassium hydrogen sulfite
Other names
Potassium bisulfite, potassium bisulphite solution, sulfurous acid, monopotassium salt, monopotassium sulfite
3D model (JSmol)
ECHA InfoCard 100.028.973
EC Number
  • 231-870-1
E number E228 (preservatives)
Molar mass 120.1561 g/mol
Appearance White crystalline powder
Odor SO2
Melting point 190 °C (374 °F; 463 K) (decomposes)
49 g/100mL (20 °C)
115 g/100mL (100 °C)
Solubility Insoluble in alcohol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Potassium hydrogen sulfite or potassium bisulfite is a chemical compound with the chemical formula KHSO3. It is used during the production of alcoholic beverages as a sterilising agent. This additive is classified as E number E228 under the current EU approved food additive.[1]


It is made by the reaction of sulfur dioxide and potassium carbonate. The sulfur dioxide is passed through a solution of the potassium carbonate until no more carbon dioxide is given off. The solution is concentrated and then allowed to crystallize. It can be of commercial, reagent or medicinal grade. It is a reducing agent, i.e it acts as a base.

Upon heating, the compound does not burn but it rather decomposes and produces corrosive and/or toxic fumes.

See also[edit]