A basic pantry staple, flour lasts a long time if you store it properly. You can't just stick a bag in the back of your pantry and forget about it, though; you may end up with rancid flour or worse, an infestation of bugs. While flour does like it cool and dark, it also fares best in an airtight container. For the freshest flavor, purchase flour frequently in smaller amounts. But when you do have reason to stock up, follow a few storage guidelines for the best results.
Producers remove the bran and germ from the wheat to make refined flour from the endosperm. The process results in a fine, soft texture and light or white color. Refined flours include all-purpose, white, bread, cake, and self-rising. These flours do not contain much oil, which causes flour to spoil when it oxidizes, making them more shelf-stable than whole-grain and other varieties.
When you bring it home from the store, put the flour in the freezer for about 5 days to kill any weevil or insect eggs that might be lurking in the package. Then transfer the flour out of the store packaging and into a food-grade container (plastic or glass) with a tight lid. This prevents moisture from creeping in and keeps insects and other pests out. It also blocks odors and flavors from other foods or products stored nearby, which could affect the aroma or taste of the flour.
Store all-purpose and other refined flours in a cool, dry place protected from sunlight. Refined flour keeps up to one year in the pantry under these ideal conditions. For longer storage, or in a warmer climate, stash the flour in the freezer, where it can last for up to two years. The cold does not noticeably affect the texture, so you can easily scoop out just the amount you need, but let the flour come to room temperature before you use it for best results, especially when baking.
Whole-Grain and Other Specialty Flours
Whole-grain flours contain the bran and the germ along with the endosperm, making them high in fiber and nutrition but also prone to spoiling faster because the bran and germ contain oils that ruin the flavor when they oxidize. Whole grain flours include whole wheat, oat, rice, rye, nut (such as almond flour), and seed varieties.
Freeze whole-grain flour for about 5 days before you transfer it to an airtight container, same as with refined flour. Then store it in the refrigerator for up to six months or in the freezer for up to a year. The higher levels of natural oils in whole-wheat and other specialty flours causes them to go rancid quickly at room temperature.
Bugs and Rancid Smells
The bugs found in flour and other grains are called weevils. If you find them, chances are they came home from the store in the package of flour. Female weevils lay them inside the grain kernel, and they hatch between one and five months later. Any brownish surface on the top of the flour indicates eggs. If you're unsure, rub some of the brownish flour between your fingers; if you catch a minty odor, you have bugs. You can also tightly pack questionable flour up to the rim of a glass and make a flat surface with the help of a knife. Leave the flour exposed to sunlight for a few hours. If the tight surface appears broken, you can assume bugs were moving around. Toss the flour.
Rancid smells happen because the fats in whole grain flours oxidize when exposed to air and moisture. Over time, inadequate storage ruins the freshness of your flour, affects the result when you bake, and may even make you sick. If your flour smells musty, toss it.
Adhere a label to your plastic or glass container of flour, noting the type and the date of purchase. This allows you to track the age of your flour and start checking its freshness at the appropriate time.
Follow these guidelines to determine the quality of the flour in your pantry:
- Refined flours such as all-purpose, pastry, and self-rising keep fresh for up to two years. Trust your sense of smell to determine if they passed their prime; spoiled flour smells sour.
- Nut or seed flours such as almond, flax, and hemp store better in the freezer, where they last up to a year. A burnt or bitter taste indicates spoilage.
- Whole-grain flours such as wheat, spelt, and barley spoil much more quickly, with a shelf-life of 3 to 6 months. Keep them in the fridge and check the expiration date before you use them. A funny smell indicates it may be time to discard them.
Finally, do not combine new and old packages of flour since doing so shortens the shelf life of the new flour.
Colorado School of Public Health. Flour: Food source information. Published 2021.
Flinn P, et al. Cold temperature disinfestation of bagged flour. Journal of Stored Products Research. 63 (2015).
Hughes J, Vaiciurgis V, Grafenauer S. Flour for Home Baking: A Cross-Sectional Analysis of Supermarket Products Emphasising the Whole Grain Opportunity. Nutrients. 2020;12(7):2058. doi:10.3390/nu12072058
Government of Western Australia: Department of Primary Industries and Regional Development. Stored food insects. Published 2021.
The Whole Grains Council. Storing whole grains. Published 2021.