Does Flaxseed Go Bad? Whole and Ground Flaxseed 101

Here’s all you need to know about the storage and expiration of whole and ground flaxseed. Learn if flaxseeds go bad, how to store them, and how to tell your flaxseeds have gone bad.

You bought a pack of flaxseed to give your smoothies a boost, but after a week of regular use, you’ve fallen off the wagon.

Now, a couple of months later, you’re wondering: does flaxseed go bad?

Or maybe your flaxseed is already past its date, and you want to know what happens when you eat “expired” flaxseed.

Sounds familiar? If so, this article is for you.

I divided this article into two sections: whole flaxseed and ground flaxseed. There are noticeable differences between the two, so it makes sense to treat them separately.

Use the table of contents to navigate to what you’re looking for.

A bowl of flax seeds on a wooden table
A bowl of flaxseed on a wooden table

Table of Contents

Whole Flaxseed

Does Flaxseed Go Bad?

Whole flaxseed lasts a long time, but it’s not impervious to spoilage. Here’s what to look out for:

  • Rancidity. The shell protects the seeds very well, but given enough time, the seeds could go rancid. Flaxseeds are rancid if they give off a chemical odor that might remind you of old paint or nail polish remover. A bitter or sour taste is another sign of rancidity, but to properly taste the seeds, make sure you crush them with your teeth and lick the powder.
  • Pantry bugs. Whole flaxseed usually sits in the pantry, so if you have an issue with pantry bugs, you might as well find them in the package. If you notice any insects, bugs, or eggs, discard the contents of the bag or container.
  • Mold. While it’s unlikely, if enough water and some contaminants get inside the bag or container, mold might start to grow. If that’s what’s happened, your seeds are gone.

(Other seeds show similar spoilage signs, so if you’re wondering how to tell if chia seeds are bad or when sunflower seeds are spoiled, I saved you a few clicks.)

Now, what happens if you eat rancid flaxseed?

The worst that’s likely to happen is that you’ll notice that they taste pretty bad, especially if you grind them. And you might suffer from some digestive discomfort a couple of hours after consumption.

That said, it doesn’t mean you should eat all your rancid flaxseed because you can’t taste it in a smoothie or yogurt.

You should still toss it because while there usually aren’t any immediate consequences of eating rancid oil, there might be some long-term negative effects of doing so.

The same is true if you’re eating or using rancid olive oil or canola.

Brown Flaxseed
(credit: AlishaV)

How Long Does Flaxseed Last?

 PantryFridge
Flaxseed (unopened and opened)1 – 2+ years 
Ground flaxseed 3 – 4 months

Whole flaxseed lasts at least 1 to 2 years in a storage container away from sunlight. After you grind the seeds, their storage time drops to about 3 to 4 months, and you need to refrigerate or freeze them.

Each flaxseed bag has a date printed on the label, and that date is usually between a year and two years after the packaging date.

That date is also only a rough estimate of how long the seeds will stay good for. And in almost all cases, they keep well past the given period.

So if you notice that your flaxseeds are “expired,” there is no need to worry. Just check the seeds for the signs of spoilage I outlined earlier, and if everything seems okay, feel free to eat them.

How to Store Flaxseed?

Store whole flaxseed in a dark place sealed tightly in an airtight container or resealable bag. It doesn’t require refrigeration, so storing the seeds somewhere in the kitchen or pantry is perfectly fine.

The hard hull keeps the seed fresh and protects it from the environment, so it doesn’t require much in terms of storage.

Once you open the package, you can leave the seeds in the original packaging if it’s resealable, or transfer them to a resealable bag or container. A tight seal is highly recommended because it keeps any moisture and pantry bugs at bay.

Of course, you can refrigerate whole flaxseed if you want, but leaving it at room temperature is perfectly fine. Refrigeration becomes useful only after you grind the seeds.

Speaking of which, let’s talk about ground flaxseed.

Handful of flax seeds
(credit: Gesina Kunkel)

Ground Flaxseed

Ground flaxseed and flaxseed meal (or flax meal) are one and the same thing. I use the former term below.

Please note that there’s also flaxseed oil available on the market, and it’s, as you might imagine, oil pressed from flaxseed. Unlike grapeseed oil, it’s not used as cooking oil but sold as a supplement instead.

Does Ground Flaxseed Go Bad?

Ground flaxseed can go rancid if it’s stored for too long or not refrigerated. It can also grow mold if the container or bag isn’t sealed tightly and moisture gets inside.

Toss your ground flaxseed if the seeds smell rancid or sour, or if the powder tastes bitter or off in any other way. Those are typical signs of rancidity.

(If you want to learn more on the topic, check out my article on signs of rancidity in oil.)

Also, discard ground flaxseed if you notice any mold in the package or if there are hard blocks or clumps of ground flaxseed. Both are a sure sign water got inside the bag or container.

Now, let’s talk about storage time.

Info

In case you wonder why people grind flaxseeds, the reason is simple: ground flaxseeds have the nutrients more readily available.

Bread with seeds
(credit: Wesual Click)

How Long Does Ground Flaxseed Last?

Ground flaxseed lasts at least 3 to 4 months when stored in an airtight container in the fridge. But if you leave it on the counter or in the pantry, it’ll probably go rancid within a couple of weeks, depending on the temperature.

Unlike whole flaxseed, the ground powder has a pretty limited shelf life and refrigerating it is highly recommended.

When you buy packaged ground flax seeds, you should expect the best-by or use-by date to be between 3 to 6 months of packaging, depending on the seller. And because of the short storage time, ground flaxseed usually comes in fairly small packages.

For homemade ground flaxseed, try to use it within a few weeks to get the most health benefit out of it. But as long as you refrigerate it sealed tightly, it should retain decent quality for a couple of months.

Finally, let’s tackle storage.

Does Ground Flaxseed Need to Be Refrigerated?

Ground flaxseed doesn’t require refrigeration, but it goes rancid quickly if you leave it at room temperature. Because of that, it’s much better to refrigerate it, and that’s what most sellers recommend.

When storing ground flax seeds, transfer the powder into an airtight container, and refrigerate. You can also place that same container in the freezer if you want to prolong the shelf life even further or don’t have room in your fridge.

The ideal way to always have your ground flax fresh is to store it whole and grind it as you go. If that’s not an option due to time constraints, you can grind it in batches, and refrigerate the leftovers.