Does King Arthur Flour Contain Bromine (Potassium Bromate)?

November 11, 2025 •

2 min read

According to the official King Arthur Baking Company website, their flours have never contained bromate. This means that anyone asking, "does King Arthur flour contain bromine?" can be confident in a negative response, a policy driven by the company's commitment to using unbleached and unbromated ingredients.

Quick Summary

An examination of King Arthur Baking Company's flour reveals it is intentionally manufactured without potassium bromate, the additive often mistakenly called 'bromine.' This is part of the company's commitment to quality and food safety, differentiating its products from some mass-market alternatives that still use the additive.

Key Points

No Bromates: King Arthur Baking Company confirms its flour is unbromated, meaning it does not contain potassium bromate, the chemical additive often referenced as 'bromine'.
Company Policy: The decision to avoid bromates is a core part of King Arthur's commitment to high-quality, transparent ingredients, relying on natural aging instead of chemical accelerators.
Health Concerns: Potassium bromate is classified as a possible human carcinogen and has been banned in many countries, although it remains legal in most of the United States.
Labeling Matters: To avoid bromated flour, consumers should always check the ingredient labels, as King Arthur clearly labels its products as "unbromated".
Alternatives Exist: King Arthur achieves superior dough performance through high protein content and meticulous milling, proving that effective baking doesn't require controversial additives.

King Arthur's Unbromated Promise

King Arthur Baking Company explicitly states that its flour has never contained bromate. The company's products are labeled as "Never Bleached, Never Bromated®". Potassium bromate is an oxidizing agent traditionally used in commercial baking to strengthen dough and improve rise. However, health concerns led to its classification as a potential human carcinogen under California's Proposition 65 in 1991. Many countries, including the UK and Canada, have banned bromate, although it remains legal in most of the U.S..

King Arthur avoids this additive by naturally aging its flour, a process that allows for natural oxidation and whitening. This aligns with their focus on high-quality, transparent ingredients and health.

The Science Behind Bromated vs. Unbromated Flour

Potassium bromate enhances dough strength and elasticity, leading to better gas retention and a lighter crumb. While baking should convert bromate to potassium bromide, tests have found residual levels in finished goods.

King Arthur's unbromated flours, such as their bread flour, achieve dough strength through higher protein content. Bakers using unbromated flour might adjust mixing times or use preferments to develop gluten.

Why Bakers Choose King Arthur's Approach

Health and Safety: King Arthur offers an option free from a potentially carcinogenic additive.
Ingredient Purity: The company uses American-grown wheat and no artificial preservatives.
Consistent Results: King Arthur ensures reliable baking results through quality standards and test-baking.

Comparison: King Arthur Flour vs. Bromated Flour


Feature	King Arthur Flour (Unbromated)	Bromated Flour (Found in some brands)
Bromate Content	No. Explicitly unbromated.	Contains potassium bromate (KBrO3).
Aging Process	Naturally aged over 2-4 weeks.	Chemical aging process is accelerated by bromate.
Dough Strength	Achieved naturally through high protein content and aging.	Achieved via a powerful oxidizing agent, potassium bromate.
Health Concerns	No associated health risks from this additive.	Linked to potential carcinogenic risks in animal studies.
Legality	Legal and widely accepted in the U.S. and worldwide.	Legal in most of the U.S. but banned in many other countries and specific U.S. states.
Baking Performance	Consistent, high-quality results from superior wheat and milling.	Can produce very high-volume loaves, especially in commercial baking.

Health Risks of Bromated Flour

Potassium bromate has been linked to potential health risks:

The IARC classifies potassium bromate as "possibly carcinogenic to humans" (Group 2B).
Studies have associated it with kidney, thyroid, and other tumors in animals.
Residual bromate can remain in baked goods.
The EWG advocates for a U.S. ban, citing bans in other countries.

Conclusion: Your Flour Choice Matters

King Arthur flour does not contain bromine (potassium bromate), reflecting the company's commitment to unbromated and unbleached products. This makes King Arthur a reliable choice for bakers who prioritize clean ingredients and wish to avoid potentially harmful additives. While potassium bromate can enhance commercial baking, its health concerns and international bans make it a controversial additive many consumers avoid. King Arthur achieves its baking performance through high-quality ingredients, not chemical additives.

King Arthur Baking Company's commitment to unbromated flour is a cornerstone of its brand identity.

Frequently Asked Questions

Yes, potassium bromate (KBrO3) is a chemical compound containing bromine, but the term 'bromine' typically refers to the elemental form. In baking, the concern is specifically about the oxidizing effects and potential health risks associated with the potassium bromate compound.

Some flour brands use potassium bromate as a dough strengthener and oxidizing agent. It helps the dough develop a stronger gluten structure, which improves elasticity, increases loaf volume, and provides a finer crumb texture.

Health concerns are based on animal studies linking potassium bromate to kidney and thyroid cancers. The International Agency for Research on Cancer (IARC) classifies it as a possible human carcinogen. Residual bromate has been detected in some finished baked goods.

King Arthur flour is often more expensive due to its higher quality standards, including the use of 100% American-grown wheat, a longer natural aging process, and its never-bleached, never-bromated guarantee. The company's 100% employee-owned status also affects its business model.

No, King Arthur Baking Company states that its retail wheat flours, including all-purpose and bread flours, are not enriched or fortified with extra vitamins and minerals. They made this decision based on changes in modern nutrition.

No, it is not banned nationwide, but some states like California and Utah have implemented restrictions or bans. Internationally, it is banned in many countries, including the European Union, Canada, and the UK.

To determine if a flour is bromated, you must read the ingredient label. The U.S. requires potassium bromate to be listed as an ingredient. Flours that are unbromated, like King Arthur's, will often explicitly state so on the package.