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Potassium hydroxide

Potassium hydroxide suppliers and sourcing guide

Potassium hydroxide is a strong alkali used in food processing for pH adjustment, alkalizing cocoa, and as a processing aid, and in personal care to make liquid and soft soaps. It is made by electrolysis of potassium chloride solution. It is highly deliquescent and sold as flakes, pellets or a 45 to 50 percent solution, in food, pharmaceutical and technical grades.

See suppliersWhat to ask for on the COA
Also known as
Caustic potash · Potash lye · KOH · E525
Facts checked
November 2026

Forms and grades of potassium hydroxide

Suppliers sell different products under the same name. Specify the one you need.

  • Flakes

    Solid flakes, the common form for soap makers and small batches.

  • Pellets

    Pellets for laboratory and small-scale use.

  • Solution

    Liquid potassium hydroxide around 45 to 50 percent for bulk dosing.

  • Food and NF grades

    Grades tested to FCC or National Formulary specifications, separate from industrial grades.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Total alkalinity (titration)
KOH content by acid titration; solid grades typically assay well below 100 percent because they hold water.
Potassium carbonate
Carbonate formed from absorbed carbon dioxide.
Mercury
Mercury by cold-vapor AA or ICP-MS, which depends on the production process.
Lead and heavy metals
Lead and other metals by ICP-MS against FCC limits.
Chloride, sodium and iron
Process impurities that matter in soap and cosmetic use.

Storage, lots and expiry

Storage and shelf life

Keep tightly sealed in compatible containers (not aluminum, zinc or tin) in a dry area away from acids; it pulls water and carbon dioxide from air quickly, so opened containers should be resealed at once. Shelf life follows the supplier specification, with a retest of assay and carbonate for opened stock.

Lots and expiry dates

Record assay for each lot and adjust soap and pH calculations to it, since flake purity varies. Rotate stock FEFO and keep food-grade lots apart from technical grades.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

  • 21 CFR 184.1631 identifies potassium hydroxide, also known as caustic potash, potash lye and potassa, and affirms it as GRAS with no limitation other than current good manufacturing practice.

    Source: ecfr.gov (opens in a new tab)

  • 7 CFR 205.605(b) allows potassium hydroxide in organic products but prohibits it for lye peeling of fruits and vegetables except peaches.

    Source: ecfr.gov (opens in a new tab)

  • Health Canada's List of Permitted pH Adjusting Agents, Acid-Reacting Materials and Water Correcting Agents includes potassium hydroxide, starting with margarine.

    Source: canada.ca (opens in a new tab)

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Potassium hydroxide suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking potassium hydroxide suppliers now

Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.

Sell potassium hydroxide? Request a listing

Frequently asked questions

What forms of potassium hydroxide can brands buy?

Common forms include flakes, pellets, solution and food and NF grades. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for potassium hydroxide include?

Expect total alkalinity (titration), potassium carbonate, mercury, lead and heavy metals and chloride, sodium and iron, each with its method, specification and result for that lot.

How should potassium hydroxide be stored?

Keep tightly sealed in compatible containers (not aluminum, zinc or tin) in a dry area away from acids; it pulls water and carbon dioxide from air quickly, so opened containers should be resealed at once. Shelf life follows the supplier specification, with a retest of assay and carbonate for opened stock.

What is the regulatory status of potassium hydroxide?

21 CFR 184.1631 identifies potassium hydroxide, also known as caustic potash, potash lye and potassa, and affirms it as GRAS with no limitation other than current good manufacturing practice. 7 CFR 205.605(b) allows potassium hydroxide in organic products but prohibits it for lye peeling of fruits and vegetables except peaches. Health Canada's List of Permitted pH Adjusting Agents, Acid-Reacting Materials and Water Correcting Agents includes potassium hydroxide, starting with margarine.

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