» Do Sunflower Seeds Go Bad? How Long Does It Last?

Do Sunflower Seeds Go Bad? How Long Does It Last?

Sunflower seeds are known for their health benefits. They are packed with vitamins, minerals, and antioxidants that boost our immune system, increasing our ability to fight off diseases. In this article, we answer the most common questions regarding sunflower seeds’ shelf life to help you use the seeds at their best and reap maximum benefits. Let’s start!

Do Sunflower Seeds Go Bad?

Do Sunflower Seeds Go Bad

Yes, sunflower seeds, like most food items, do go bad. How long they last, however, depends on a number of factors including how they are stored and whether they are raw, shelled, or roasted. Also, like most seeds, sunflower seeds will usually not have an expiration date. Instead, they come with a best-by or best-before date, meaning, they can still be consumed beyond this date.

Stored in the pantry, sunflower seeds can retain their quality a couple months after the printed date. But if you want them to last a little longer, consider refrigerating, or even better, store them in the freezer. According to Research Gate, the cold temperatures will help prevent the seeds from deteriorating and keep them fresh and flavorful longer.

How Long Do Sunflower Seeds Last?

As mentioned, the lifespan of sunflower seeds will largely depend on the type of seeds and the storage environment.

In the grocery store, you will often find these seeds stored amongst other varieties of oil seeds and nuts. While that may not be the most ideal storage setting, it is okay for storing the seeds short-term, say a few months, or so.

Check the date printed on the package to find out how long the seeds will stay good for. Depending on the variety, an unopened pack of sunflower seeds will last anywhere between two and five months beyond the best-by date in the pantry. Once the package is opened, it should be consumed within one month.

If you store the product in the refrigerator, you can expect it to last up to one year after the printed date. Raw sunflower seeds will have a shorter shelf life than their roasted in-shell counterparts, lasting around three months and five months respectively in the pantry.

Below is a table that summarizes it all.

Type of Sunflower Seeds Lifespan
  Pantry Refrigerator
Unopened, raw sunflower seeds Best-by + 2 to 3 months Best-by + 1 year
Unopened, roasted, shelled sunflower seeds Best-by + 3 to 4 months Best-by + 1 year
Unopened, roasted in-shell sunflower seeds Best-by + 4 to 5 months Best-by + 1 year
Opened sunflower seeds 1 month Up to 1 year if sealed properly

5 Tips to Tell if Sunflower Seeds Have Gone Bad

Tell if Sunflower Seeds Have Gone Bad

The spoilage signs of sunflower seeds will likely not be any different from other oilseeds like poppy or chia. Here are some signs to look out for.

1.    Mold

Moldy sunflower seeds will exhibit mold and fungus growth or smell musty. They will also appear somewhat discolored. In severe cases, the seeds may also feel softer than they ought to be.

The good news is that sunflower seeds rarely develop mold. However, if proper storage guidelines are not followed and water sneaks into the package, you will definitely experience this unwanted growth. Get rid of those seeds.

2.    Weird Taste

Sunflower seeds usually have a mild, nutty flavor. If yours taste sour, it is a sign that they have gone bad and you should toss them out.

3.    Sour Smell

Smell is perhaps the most effective way to find out if your sunflower seeds are safe to eat. If a packet smells sour, chances are the seeds have gone rancid. Rancidity occurs when the seeds are exposed to light, oxygen, or moisture. You will likely not get sick from ingesting the seeds but the odor will be quite awful.

4.    Outdated Best-by Date

While sunflower seeds will still be safe to eat a few months after the stated expiration date, very old seeds will lose their nutritional value.

Most of the time, the seeds may not show any obvious signs of spoilage, but if they appear dusty, dull, or dried out, they are certainly less healthy for you and should be thrown out.

5.    Presence of Insects

Insects such as weevils or moths can infest sunflower seeds especially if the product is not sealed properly. Inspect your seeds for live or dead insects, cocoons, and other signs of insect activity.

A few bugs, say, one or two, may not be a problem but a larger swarm it’s a sign that the seeds are spoiled and should not be consumed.

4 Tips to Store Sunflower Seeds

Sunflower seeds degrade over time, losing their nutritional value significantly. Storing them incorrectly could make your dream of enjoying their health benefits fall flat. Follow these tips for storing your sunflower seeds and you will be able to keep the seeds fresh and healthy longer.

1.    First Things First – Buy Fresh Seeds

When purchasing a packet of sunflower seeds, make sure to go for the freshest seeds available. Check the date printed on the package to find out how long the product will stay good for. If the seeds have been sitting on the shelf for a while, chances are they won’t last as long as you would want them to, regardless of whether you refrigerate them or not.

2.    Store in Airtight Containers

An airtight container will help keep the seeds dry by locking moisture out. A mason jar with a tight-fitting lid would be the perfect option but really, any sealable container can do the job. Just make sure it is not plastic, as the seeds can absorb chemicals from plastic and become unsafe to eat.

Properly closing the containers does not only help block moisture; it also helps keep bugs and smells from adjacent food items at bay.

3.    Place in a Cool, Dry Place

Warmth and humidity shorten the shelf life of sunflower seeds. So the pantry or fridge is generally the best place to store the product. The pantry would be a great spot for short-term storage but if you want your seeds to have a longer life, put them in the refrigerator or freezer.

4.    Squeeze Out Excess Air

After you have opened a packet of sunflower seeds, you can keep the leftover in the original pack. However, be sure to get rid of the excess air before resealing the bag.

If the packet is not resealable and you have to transfer the seeds to an airtight container, make sure to fill the container to the top so you are not leaving a space between the lid and the seeds. You want to trap as little air as possible to keep the seeds at their best quality.

Watch this video for more tips on how to properly store seeds to extend their life. You can use the same tricks for your sunflower seeds:

The Risk of Consuming Expired Sunflower Seeds

When sunflower seeds are past their best-by date, their quality starts to decline, and after some time, they become rancid. Such seeds can have a sour taste and if they were not stored properly, they could also be moldy.

Consuming such seeds can make you sick. While ingesting them in small quantities may not harm you, if you do it regularly, the toxins in the seeds can have adverse effects on your digestive system.

Depending on the amount ingested, they can cause inflammation of the stomach also known as gastritis. You may experience nausea, indigestion, vomiting, or even pass black, tarry stool in the case of erosive gastritis. If your sunflower seeds are showing signs of spoilage, it’s better to toss them out to avoid putting yourself in harm’s way.

Can You Freeze Sunflower Seeds?

Yes, sunflower seeds can be stored in the freezer to further extend their shelf life. Properly frozen sunflower seeds can stay good for about one year, but can still be consumed after that time.

If the seeds have freezer time indicated on the package, in most cases, that will be for best quality only. If you store the seeds at a constant temperature of 0° F, they will keep safe indefinitely.

So how do you freeze sunflower seeds?

Well, the most important thing is to ensure you have airtight containers. Glass containers like mason jars are excellent options but you could also use Ziplock bags.

Once you have picked the right container or bag, put the seeds inside and place them into the freezer. Pick a spot at the back where the seeds can sit undisturbed. Do not place them near the door or any other part with fluctuating temperatures.


Sunflower seeds don’t have a very long shelf life. But with proper storage, they can retain their quality long enough for you to consume them without experiencing any negative effects. Keep your seeds in the pantry for short-term storage or in the refrigerator if you want to prolong their life. For best results, ensure storage containers are tightly sealed.


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