Here’s Why Your Flour May Smell Like Crayons, According to King Arthur Experts

Flour is a kitchen essential, especially for those who bake. If you're like me, you probably have several types on hand: maybe some '00' Caputo flour for pizza, whole wheat flour for hearty loaves, and of course, all-purpose flour for everyday baking.

When I don’t use a particular bag quickly, it’s easy to forget when I bought it. The best-by date is a useful reference, but if the flour is near or past that date, how can a home cook tell if it’s gone bad?

Just like milk or meat, there’s a simple method to check if flour is still good: the smell test. If the flour gives off an off-putting odor, it’s likely spoiled. The scent can vary depending on the type of flour, though.

What Causes Flour to Smell Like Crayons?

We consulted the experts at King Arthur Baking to learn how to spot flour that’s gone sour, and they shared some helpful tips.

Flour usually has a neutral scent and shouldn’t smell off. White flour (also known as all-purpose) can be tricky to judge, but if it’s spoiled, it will take on a cardboard-like odor. Jonathan Brasil, a Research and Development Specialist at King Arthur Baking, explains, 'It may have a general stale aroma.'

'Whole wheat flour can develop a smell reminiscent of crayons, believe it or not. This happens because the fats in the flour begin to go rancid,' says Jonathan. 'The best advice is to use your flour before the best-by date.'

Whole wheat flour contains a small amount of fat, which can spoil over time. When it does spoil, it can develop a smell similar to crayons.

To extend its shelf life, whole wheat flour should be kept in the refrigerator or freezer. At room temperature or in a cool, dark cabinet, it will last around one to three months. In the fridge, it can last up to six months, and in the freezer, up to a year.

Other flours, such as almond or nut-based flours, also benefit from the smell test. If they have a sour or rancid odor, it’s best to discard them. You should also check for any discoloration, dark specks, or clumps that don’t break apart—signs that it might be time to open a fresh bag.

If you’re curious about the best methods for storing flour, King Arthur, along with Gold Medal and Pillsbury, shared their expert tips on the subject.