The Must-Know Sign That Your Flaxseeds Have Gone Bad

We've got all the details on how to store flaxseeds and flaxseed meal properly. Follow our Test Kitchen-approved tips to make that package last as long as possible, so you can keep adding those healthy little seeds to smoothies, breads, oatmeal, and more.

So you started adding flaxseed meal to your morning smoothies and a few months later find an opened bag in the back of your pantry. Can flaxseeds or ground flaxseed (aka flaxseed meal) go bad? Yes, just like any seed, they will eventually turn. But before you toss that package, use our pointers to find out if it's still okay to use. After we cover some flaxseed basics, we'll go over how long you can store flaxseed and how to tell if it's still safe to eat. You'll also learn how to store flaxseeds, so they last as long as possible to add to that bread recipe or when you need a vegan egg substitute.

a pile of flax seeds on a textured surface
Whole flaxseeds are a little bigger than sesame seeds. Blaine Moats

What Is Flaxseed?

Before it's dried and harvested for its seeds (aka linseed in some places), flax blooms as a blue-flowered perennial plant. Historically, flax plant crops were grown in the U.S. for their fibrous stalks, which could be turned into material for clothing. Today, the seeds are used as a versatile (and affordable) way to add fatty acids, fiber, and iron to your diet. Flaxseeds are slightly nutty in flavor and can be consumed whole or ground, but is recommended by most nutritionists to consume ground. Ground flaxseed is easier to digest, so you'll reap more of their health benefits.

Does Flaxseed Go Bad?

All commercially-purchased flaxseeds have an expiration date on the package, but that doesn't necessarily mean it has to get tossed as soon as that date arrives. How long flaxseeds lasts depends on how they were processed, where you're storing, and which form (seeds or ground) you've got. If you have whole flaxseeds, they can last months past the expiration, especially if stored in the fridge (more on that below). As for ground flaxseed, it could go bad as soon as a week after the expiration date. The best way to tell if your flaxseed product is rancid is to give it the smell test. When past their prime, those omega-3s inside the seeds release an off-putting sour odor. If it didn't pass the sniff test or there is any sort of bitter flavor, that's the sign to throw your flaxseeds or flaxseed meal out.

How to Store Flaxseeds

Keep your flaxseeds fresher longer by keeping them in an airtight container. Whole or ground, it's not required to be stored in the fridge. A cool, dark pantry should be fine. Though just as storing nuts in the fridge increases their shelf life, the same goes for flaxseeds and flaxseed meal. According to the USDA's Foodkeeper App, flaxseeds will last up to a year when stored in the fridge or freezer.

If you don't think you'll go through a bag of flaxseed meal ($5, Target) quick enough, opt for purchasing longer-lasting whole flaxseeds. Then you can grind the amount you need for your zucchini muffins or salad dressing.

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