Does Flax Seed Go Bad? How Long Does It Last?

Written by: Mike Marshall
flax seed in a bowl

Found an old packaging of flax seed in the pantry and wondering if it’s still good? Actually, you might be thinking – does flax seed go bad at all?

In short – yes, but it stays fresh for a very long time.

In this article, we’ll go over everything you need to know about flax seed, from shelf life to best storage practices. 

Keep reading to find out more!

How Long Does Flax Seed Last?

If you buy a bag of flax seeds at the grocery store, an expiration date will be printed on the packaging. 

But the date on the label is merely a guideline on how long will the flax seeds keep their freshness. If you store it properly (and we’ll talk about that in the last section), you can probably use flax seeds way past their official expiry date.

Whole flax seeds can last months after the date on the label. That’s thanks to the hard outer shell that keeps the oil content inside safe from air, heat, and moisture. Generally, you can keep them stored at room temperature for up to 10 months without going rancid

Ground flax seeds, on the other hand, don’t last near as much. Without a protective layer, the shelf life is about 4 months at room temperature.

When it comes to an ideal temperature for storing seeds, it’s somewhere between 35 and 40 degrees Fahrenheit. That’s why keeping flax seeds in a fridge can extend their shelf for a couple more months. 

Freezing flax seeds will keep them fresh for a bit longer. Whole flax seeds can be stored in a freezer for up to two years, while ground will stay fresh for about a year or so. 

Because flax seeds generally come in non-airtight packaging, the shelf life is the same whether the bag has been opened or not. Still, transferring them to an airtight container after opening assures they don’t degrade faster as a result of oxygen exposure.

At Room TemperatureRefrigeratedFrozen
Whole Flax Seeds10 Months1 Year1-2 Years
Ground Flax Seeds4 Months~6 Months~1 Year

How To Tell If Flax Seed Is Bad?

Flax seeds don’t go bad in the traditional sense of the word. That’s why you usually won’t see obvious signs of spoilage, such as mold formation or foul odor. 

Don’t get me wrong – flax seeds can go moldy, especially when ground. 

But that will only happen if you, let’s say, leave a wet spoon in the container. If you keep it away from moisture, such issues are not something you’ll have to worry about.

But because they contain omega-3 and omega-6 fatty acids, flax seeds will go rancid in time. 

To find out if your seeds are still fresh or not, pay attention to these cues.

Rancid flax seeds will have a somewhat sour or chemical smell that resembles old paint.

As for the taste, they’ll become bitter as a result of rancidity. If you’re unsure if your flax seeds are still edible, the best way to determine their freshness is to take a bite.

But just because they turned a bit bitter, that doesn’t mean flax seeds will necessarily taste bad. Still, you shouldn’t eat food that has gone rancid. 

Rancidity kills all the beneficial nutrients in fatty acids. But not just that. It also causes the development of some toxic compounds that can cause serious health issues.  

How To Store Flax Seed

flax seed in a glass jar

The best way to store any seeds is to keep them in a dry and cool place. Flax seeds are no different. 

But as we already established, they’re rich in oils that go rancid when exposed to oxygen. For that reason, you should always transfer flax seeds to an airtight container after opening the packaging. 

Ideally, you want to use an opaque container, to keep flax seeds away from direct sunlight. If you must use transparent packaging, make sure to store them in a cabinet or pantry, away from light exposure.

If you wish to extend the shelf life, you can store flax seeds in the refrigerator or freezer. In both cases, it’s important to use an airtight container to prevent moisture from getting in. 

Just keep in mind that once thawed, flax seeds will go rancid at a much faster pace. That’s because freezing changes the oil structure.


Flax seeds are rather shelf-stable and can last for months when stored at room temperature. 

You can further extend the shelf life for a few more months by storing them in the fridge or freezer.

The biggest enemies of flax seeds are light, air, and moisture. 

For that reason, you should always transfer them to an airtight container and store them in a dry and cool place.

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I’m not a pro chef by any means, but years of tinkering inside the kitchen have taught me a thing or two about preparing delicious, healthy food. So whether you’re interested in how to properly store food, figuring out side dishes for your main course, or even learning how to use a knife properly – I've got you covered.