Comparing E524 - Sodium hydroxide vs E525 - Potassium hydroxide

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Overview

E524 - Sodium hydroxide

Sodium hydroxide (E524), also called lye or caustic soda, is a strong alkali used in small, controlled amounts in food processing. It helps adjust acidity (pH), loosens peels on fruits and vegetables, and creates the classic deep-brown crust on pretzels.

E525 - Potassium hydroxide

Potassium hydroxide (E525) is a strong alkaline ingredient used to control acidity in foods. In tiny, carefully measured amounts it helps keep products stable in taste, color, and texture, and it can also be used to help peel some fruits and vegetables during processing. It’s sometimes listed on labels as potassium hydroxide or E525.

Synonyms

E524

Sodium hydroxide

Caustic soda

E525

Potassium hydroxide

Functions

acidity regulator

Origins

Synthetic

Mineral

Products

Found in 393 products

Found in 11 products

Search rank & volume

#5258K / mo🇺🇸U.S.

#9621.1K / mo🇺🇸U.S.

Awareness score

×21.32

over-aware

×192.66

over-aware

Search volume over time

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

Interest over time for 2 keywords in U.S. during the last 10 years.

Popular questions

What is sodium hydroxide used for?
In foods, E524 (sodium hydroxide/lye) is used as a pH regulator and processing aid—for peeling fruits and vegetables, curing olives, Dutch-processing cocoa, and creating the characteristic crust on pretzels and some noodles. Outside food, it’s widely used in soapmaking, cleaning, and pulp and paper production.
Is sodium hydroxide a base?
Yes—it's a very strong base (alkali) with a high pH and is highly caustic; in foods it's used only in small, controlled amounts.
What is the chemical formula for sodium hydroxide?
NaOH.
What is the formula for sodium hydroxide?
NaOH (composed of sodium cations, Na+, and hydroxide anions, OH−).
How to make sodium hydroxide?
Industrial sodium hydroxide is produced by the chlor-alkali process (electrolysis of brine), yielding NaOH, chlorine, and hydrogen. Do not attempt to make it yourself; for any food use, only purchase certified food‑grade lye.