Potassium bromate

August 13, 2018
Beware of using me for baking.
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Potassium bromate (KBrO3) is a typical potassium salt in that it is water-soluble and has a high melting point. The bromate anion is a potent oxidizer.

KBrO3‘s only significant commercial use is as a “flour improver” in bakeries. According to the Professional Baker’s Reference in the King Arthur Flour Web site, it “strengthens dough and allows for greater oven spring and higher rising in the oven.” The reference states that KBrO3 is a “slow-acting” oxidizer, which means that it is effective during the mixing, fermentation, and proofing stages of the baking process.

Used properly, KBrO3 is completely consumed by the end of baking. But because good baking practices may not always be used, its carcinogenicity (see hazard information box), prompted its ban in the early 2000s in the European Union, Canada, China, South Korea, and some South American countries. Its use is still legal in the United States, but California’s Proposition 65 law dictates that bromated flour must be labeled as a carcinogen.

Potassium bromate hazard information

GHS classification*: oxidizing solids, category 1
H271—May cause fire or explosion; strong oxidizer Chemical Safety Warning
GHS classification: acute toxicity,oral, category 3 
H301—Toxic if swallowed  Chemical Safety Warning
GHS classification: carcinogenicity, categories 1A, 1B
H350—May cause cancer  Chemical Safety Warning

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

Potassium bromate
fast facts

CAS Reg. No. 7758-01-2
Molar mass 167.00 g/mol
Empirical formula KBrO3
Appearance White crystals or powder
Melting point

350 ºC

Water solubility 75 g/L
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