How Long Does Cereal Last? (Open, Unopened, Long-term Storage)

Cereal is one of the most popular breakfast choices globally, but many people don’t know exactly how long it lasts. If an old box of cereal is found at the back of a cupboard that’s past its best by date, you may be wondering if it can still be consumed.

Cereal can often last up to 12 months past the recommended date on the packaging and opened cereal can last up to 6 months past the suggested date. Cereal doesn’t go rancid in the same way that milk does, so it can be kept in the pantry or cupboard for months without worrying about it spoiling.

This article will explain how long cereal lasts and the best ways to store it long-term in greater detail. If you want to learn more about these topics, be sure to keep reading!

An image of a generic cereal box on a wooden table.

How Long Does Cereal Last?

Unopened cereal lasts up to 12 months after the best by date and opened cereal lasts up to 6 months past the date. However, this is simply a general consensus; cereal can often be consumed beyond 12 months, or it might go stale much quicker; it depends on the storage conditions.

Since cereal is dry and only contains 12-14 percent water, it’s unlikely that mold will grow on it. Once it’s unopened or sealed well, it can last a very long time. There’s also no need to store cereal in the fridge because it’s nonperishable; room temperature is just fine!

How Long Does Cereal Last After Opening?

After opening, cereal can last 6 months past the expiration date. It can even last beyond this, but the quality won’t be as high. Keeping the cereal sealed as much as possible maximizes the amount of time it will last, so it’s a good idea to close the packaging every time you’re finished.

In a particularly humid area, the cereal might gain some extra water content; this could cause it to go rancid and not last as long. Keep that in mind if you live somewhere that’s hot and humid.

How Long Does Cereal Last Unopened?

Unopened cereal stored in a dry cupboard can last many months past the recommended date. Since it’s unopened, the cereal is protected from moisture and extra oxygen, which can cause it to go stale more quickly. Storing it in a cool, dry place also helps it last longer.

After stocking up on a few boxes of cereal, don’t worry about them expiring any time soon. However, if there is an unopened box of cereal that has been stored for more than a few months, it’s always best to smell it and check the texture once it has been opened.

How Long Is Cereal Good For?

Cereal is good for 6-12 months past the best by date. It won’t stay good for as long if it’s opened. Even if it’s sealed well, it will lose its crispiness and freshness within a few months. It’s still generally safe to eat cereal if it’s gone stale, but it may be soft and unpleasant.

How long cereal is good for also depends on how it is stored. It’s best to keep it in a cupboard that’s dry and cool, or a pantry to keep it good for as long as possible. Cereal won’t stay good for as long in the sun or wet conditions, so make sure to store it appropriately.

How do you know that cereal has gone bad?

To know if your cereal has gone bad, look out for the following:

  • Texture. If the texture of the cereal is soft, it indicates that the cereal is stale and won’t taste as good. However, it’s still safe to eat.
  • Smell. If the cereal has an odd or unpleasant odor, it’s likely gone rancid and should be disposed of.
  • Taste. Like with smell, if the taste is unpleasant, you should dispose of the cereal because it’s likely gone bad and could even make you ill.
  • Appearance. If mold is growing on the cereal, you should throw it away. However, mold doesn’t usually grow on cereal because of its dryness.
An image of Oatmeal in Mason Jar.

Do Cereals Really Expire?

Cereals don’t really expire, so it’s generally safe to eat them past the recommended best by date on the packaging. Even though cereal doesn’t really expire, it does lose some taste quality after a few months. Eating it after a few months is fine, but it likely won’t taste the best.

Many people throw their cereal out once they notice that the date on the packaging has passed, but this is often not necessary and even wasteful.

In fact, the average American wastes approximately one pound of food every day, which certainly adds up when you think of the country’s population! So, using cereal past the best by date instead of throwing it out helps to reduce waste and save money.

The date on cereal packaging technically isn’t an expiration or use by date at all; it’s simply an estimate for how long the cereal will stay at its peak quality.

So, use your best judgment to decide whether to dispose of cereal or not. If it’s past the date on the packaging and you want to throw it out, be sure to check the quality. It might not need to be thrown out at all if the quality is still high!

Is It Safe to Eat Expired Cereal After Sell by or Best by Date?

It is perfectly safe to eat cereal after the sell-by and best-by dates. These dates are just general guides and don’t need to be followed too closely when eating cereal. Even though a store isn’t allowed to sell cereal after the sell-by date, it’s generally OK to eat it beyond this date.

Now, if you do try a box and realize that the taste is just not something you or your family can handle? Then it’s going to be your call if you power through that box or if you discard it.

That is, of course, provided it’s not failing the “is it still safe to eat” sniff test. When in doubt, throw it out. Food poisoning isn’t fun.

Different types of date recommendations

There are different types of date recommendations on food packaging, so it can be difficult to know which ones are more important. The most common types of dates are:

  • Sell by. The sell by date indicates when a product should be sold. Once the sell by date has passed, the store can no longer sell the product. However, this doesn’t mean that you can’t consume it after this date.
  • Use by. The use by date indicates how long it’s safe to eat a product. If it’s passed the use by date, the product is no longer at its peak quality and is more likely to be rancid. It’s generally not a good idea to consume food that has passed the use by date, with the exception of cereal.
  • Best by. The best by date is what you commonly see on cereal and other nonperishable  packaging. It is merely a guide, but food can almost always be consumed after the best by date if it’s stored appropriately.

Personally, I’ve eaten food that’s past each of these recommended dates. Sometimes I’ve regretted it (usually with milk), and sometimes it’s been just fine. Then again, there are also times when foods are well within all the dates above, and it still tastes off. If it tastes or looks off (and it’s within those dates) I still throw it out. I don’t want to get sick, thanks.

An image of a young blonde woman doing shopping of cereals in the store.

How Long Does Baby Cereal Last?

Unopened baby cereal can last for a few months past the expiration date. Once it has been opened and prepared, it only lasts for up to three days in the fridge. This is because baby cereal is generally mixed with regular or breast milk, both of which go rancid quite quickly.

Most baby cereal packaging recommends using the product within a month of opening, as long as you haven’t prepared it yet.

Again, please use your best judgment. Don’t be putting your baby’s health at risk if you can avoid it.

Baby rice cereal

Baby rice cereal lasts for approximately 2-3 days once it’s been cooked. Don’t risk feeding your baby prepared rice cereal that’s been sitting in the fridge for more than three days because the milk or other liquids in it will likely be rancid.

It’s best to prepare rice cereal in small portions so that it doesn’t need to be kept in the refrigerator, and so that there is no risk of your baby getting sick. Make sure to store any prepared rice cereal in the fridge and not at room temperature. It will go bad a lot quicker at room temperature.

Baby oatmeal cereal

Like baby rice cereal, baby oatmeal cereal also lasts for 2-3 days in the refrigerator once it’s been prepared and cooked. It must be stored in the refrigerator when it’s been prepared and avoid leaving it out at room temperature for more than an hour or two.

Unprepared baby oatmeal can last around six months when opened if it’s stored in a cool dry place and if it’s in an air-tight container. It can last up to two years if unopened and must be stored somewhere cool and dry also. The ideal room temperature is between 50 and 70 degrees Fahrenheit.

How to Store Cereal Long-Term

Cereal should be stored in a cool, dry place; a pantry is an example of a great place to store cereal. If you don’t have a pantry, keep it in a cupboard where there is no sunlight. Cereal does best at room temperature, so there’s no need to store it in the refrigerator.

Cereal can be stored with other nonperishables, such as pasta and canned foods. If it’s been opened keep it sealed tightly. If cereal isn’t sealed after opening the box, it can go stale in as little as a few days.

If cereal is kept in the box after opening it, be sure to close the box and the plastic bag that it’s in. Only cut a corner of the plastic bag when opening the bag of cereal; this means less air can get into it, and it will take longer to go stale.

If cereal is transferred into a container, make sure it’s as air-tight as possible; this will help it stay fresh and crunchy for longer.

Original packaging vs. container

If planning on storing opened cereal in your home for more than a few weeks, it’s best to transfer it into a plastic or glass container. The cereal will go stale more quickly in the original packaging since the box and plastic bag aren’t air-tight once opened.

By keeping the cereal in an appropriate container, it’s protected from moisture and oxygen. Not only will it keep the cereal fresher, but it also looks better and can make the cupboard or pantry look more organized!

Key Takeaways and Next Steps

Cereal can last for many months after the best by date. As long as it’s stored in a dry place at room temperature, you shouldn’t run into any problems. The most important things to remember are:

  • Unopened cereal can last up to 12 months past the best by date.
  • Opened cereal can last up to 6 months past the best by date.
  • Even if cereal is stale, it’s not unsafe to eat.
  • Cereal generally doesn’t expire.
  • It’s best to store cereal in an air-tight container for long-term storage.

For more information about long-term food storage, I’ve got lots of articles to keep you going. Let’s think of it as a “choose your own adventure” kind of game, so pick what you want to read next:

They’re all packed full of great information that will help your food storage skills go up a notch, so enjoy whichever one draws your attention.

An image of cereals stored in kitchen jars.

Cite this article as: “How Long Does Cereal Last? (Open, Unopened, Long-term Storage).” Backyard Homestead HQ, 11 February 2022, backyardhomesteadhq.com/how-long-does-cereal-last-open-unopened-long-term-storage/.

Resources

It’s important to learn from your own experience, but it’s also smart to learn from others. These are the sources used in this article and in our personal research to be more informed as homesteaders.

  • Conrad, Zach, et al. “Relationship between Food Waste, Diet Quality, and Environmental Sustainability.” PLOS ONE, edited by Benedetto Marelli, 2018, journals.plos.org/plosone/article?id=10.1371/journal.pone.0195405
  • “Home | Food and Agriculture Organization of the United Nations.” PRD-FAOHome, Food and Agriculture Organization of the UN, www.fao.org/home/en. Accessed 29 Jan. 2022.
  • “A Shelf Life Guide.” Cerritos College, Jan. 2018, www.cerritos.edu/basic-needs/_includes/docs/ShelfLifeGuide.pdf

By Kimberly Starr

I'm a ginger who loves being outside, homesteading, and spending time with my family. I believe humor is the best medicine, followed very closely by chocolate and tacos.