Potassium hydroxide

E number E525INS 525CAS 1310-58-3

Used as an acidity regulator.

Potassium hydroxide is a strongly alkaline acidity regulator and processing aid, used in cocoa processing, olive curing and as a peeling agent for fruit.

Where it is and isn’t permitted

Status of Potassium hydroxide by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 184.1631retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFAPermitted, with conditions

7 food categories

highest permitted level 2,000 mg/kg

Show every food category
  • 01.1.2 Other Fluid Milk (plain) — GMP
  • 01.2.1.2 Fermented milks (plain), heat-treated after fermentation — GMP
  • 01.8.2 Dried whey and whey products, excluding whey cheeses — GMP
  • 13.1.1 Infant formulae — 2,000 mg/kg
  • 13.1.2 Follow-up formulae — GMP
  • 13.1.3 Formulae for special medical purposes for infants — 2,000 mg/kg
  • 13.2 Complementary foods for infants and young children — GMP
CXS 192-1995 Table Three, INS 525and 7 further provisionsretrieved 2026-09-07

What it is made from

Manufactured by the electrolysis of potassium chloride solution.

  • Vegan
  • Vegetarian
CAS registry number
1310-58-3
InChIKey
KWYUFKZDYYNOTN-UHFFFAOYSA-M
PubChem
CID 14797

Every name it appears under

65 recorded names. A label may use any of them.

E number

  • E525

INS number

  • 525

CAS registry number

  • 1310-58-3

As it appears in regulation

  • Potassium hydroxide

Other names

  • 0.1M Potassium hydroxide
  • 0.5M Potassium hydroxide
  • 11M Potassium hydroxide
  • Acid Number (AN) Standard: 0.1 mg KOH/g in Hydrocarbon Oil
  • Acid Number (AN) Standard: 0.5 mg KOH/g in Hydrocarbon Oil
  • Acid Number (AN) Standard: 1.0 mg KOH/g in Hydrocarbon Oil
  • Acid Number (AN) Standard: 1.5 mg KOH/g in Hydrocarbon Oil
  • Acid Number Standard 0.1 mgKOH/g. Reference materials intended for use in the determination of Acid
  • Acid Number Standard 0.5 mgKOH/g. Reference materials intended for use in the determination of Acid
  • Acid Number Standard 1 mgKOH/g. Reference materials intended for use in the determination of Acid Nu
  • Acid Number Standard 2 mgKOH/g. Reference materials intended for use in the determination of Acid Nu
  • Acid Number Standard 3 mgKOH/g. Reference materials intended for use in the determination of Acid Nu
  • Aetzkali
  • Base Number (BN) Standard: 10 mg KOH/g in Hydrocarbon Oil
  • Base Number (BN) Standard: 15 mg KOH/g in Hydrocarbon Oil
  • Base Number (BN) Standard: 30 mg KOH/g in Hydrocarbon Oil
  • Base Number (BN) Standard: 40 mg KOH/g in Hydrocarbon Oil
  • Base Number (BN) Standard: 6 mg KOH/g in Hydrocarbon Oil
  • Base Number (BN) Standard: 70 mg KOH/g in Hydrocarbon Oil
  • Base Number Standard 10 mgKOH/g. Reference material intended for use in the determination of Base Nu
  • Base Number Standard 30 mgKOH/g. Reference materials intended for use in the determination of Base N
  • Base Number Standard 6 mgKOH/g. Reference materials intended for use in the determination of Base Nu
  • Caswell No. 693
  • Caustic potash
  • Caustic-potash
  • CCRIS 6569
  • Cyantek CC 723
  • E 525
  • EPA Pesticide Chemical Code 075602
  • HSDB 1234
  • Hydroxyde de potassium
  • hydroxyl potassium
  • INS NO.525
  • INS-525
  • Kali causticum
  • Kalilauge
  • Kaliumhydroxid
  • Kaliumhydroxyde
  • KOH
  • MIRACLE WATER 3 in 1
  • Potash caustic
  • Potash lye
  • Potassa
  • Potasse caustique
  • Potassio (idrossido di)
  • Potassium (hydroxyde de)
  • potassium -hydroxide
  • potassium hydorxide
  • potassium hydoxide
  • Potassium hydrate
  • potassium hydroxid
  • Potassium hydroxide
  • Potassium hydroxide (K(OH))
  • Potassium Hydroxide (Semiconductor Grade)
  • Potassium Hydroxide (~85%)
  • Potassium hydroxide, flake
  • Potassium hydroxide, pellets
  • potassium hyroxide
  • potassiumhydroxide
  • WZH3C48M4T

Systematic names

  • potassium hydroxide

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07
  • gsfa retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/potassium-hydroxide.json