Can Oatmeal Go Bad? (Find Out Here)

Oats are a long-lasting food source and some types of oatmeal last longer than others. Let’s find out if oatmeal can go bad.

Cooked oatmeal can go bad after a few hours if it’s left unrefrigerated. After refrigerated, cooked oatmeal will go bad after one week. Uncooked, dry oats will go bad in 2-3 years but its quality will decline after the best if used before date on the package.

This article will dive deep into how long every kind of oatmeal (cooked, dry oats, instant, steel cut, rolled oats, refrigerated) will last before it goes bad. In addition, I will inform you the best way to store oatmeal and how to know it’s gone bad.

As a Certified Health Coach I have researched and studied everything about oatmeal. I store and consume oatmeal multiple times a week, all year long. I love oatmeal, so let’s take a close look.

How To Tell if Oatmeal Is Bad?

Kevin Garce's bowl of oatmeal in his kitchen.
A bowl of oatmeal in my kitchen this morning I made it with bananas cinnamon and blueberries

The best way to tell if cooked oatmeal is bad, is to smell it and look for color changes. Check for any other anomalies like mold growth. If it doesn’t smell correct, changed color or has mold, the oatmeal is bad. 

If any of the above is present, throw the oatmeal away, as ingesting it could result in illness.

The best way to tell if dry, uncooked oatmeal has gone bad is to smell it, check its color and the best if used before date on the package. If the dry oatmeal smells, changed color, has mold or is well after the package date, it is bad.

If any of the above is present, throw it away, as ingesting the bad food may result in illness.

Dry oats can last for a long time if stored in a cool, dry place1. If you notice an “off” smell, or if it smells stale, it’s probably best to throw it out.

Oatmeal doesn’t go bad immediately past its expiration date, but it slowly loses its nutritional value, quality and may change in texture. The lipids in oatmeal will go bad over time, giving it a rancid, sour-like flavor.

Typically the expiration date indicates when food is best. What most call the expiration date is really best if used before date. However, this is no indication of how safe it is to eat2. 

Rancid oatmeal doesn’t taste great, but it shouldn’t cause any foodborne illness. If oatmeal does taste slightly off and is far past the best if used by date, it may be best to throw it out.

How Long Does It Take for Instant Oatmeal To Go Bad?

If stored properly, instant oatmeal in the packets are good for 1 to 2 years. However, if you open the package and then change your mind about eating it, it can go stale much quickly3.

Instant oatmeal goes bad far quicker than steel-cut oats, but it still has a respectable shelflife. 

How Long Do Steel-Cut Oats Last?

Steel-cut oats stored properly last for 3 to 5 years. 

In addition to being more nutritious, unprocessed4 steel-cut oats last longer than instant oatmeal. However, if you want to keep steel-cut oats fresher longer, try storing them in the freezer.

How Long Do Rolled Oats Last?

Rolled oats last between 1 and 2 years if it’s stored properly. 

Since they are more processed than steel-cut oats, their shelf-life is reduced slightly. Rolled oats and instant oatmeal have a similar lifespan, as they are both flattened to reduce cooking time5.

How Long Does 1-Minute Oatmeal and 5-Minute Oatmeal Last?

Both 1-minute oatmeal and 5-minute oatmeal last for 2 to 3 years. 

Instant oatmeal can be cooked quickly and has a long shelf life, making it ideal for most people. Again, if you notice a rancid or stale smell, you may want to throw it out.

Kevin Garce storing oatmeal in his kitchen cabinet at home.
Storing 1 minute oatmeal in my kitchen cabinet at home

Can Oatmeal Go Bad After It Is Cooked?

Oatmeal can go bad after it is cooked. Cooked oatmeal unrefrigerated after two hours will start going bad. Bacterial growth will cause it to spoil after two hours, therefore it should be discarded. 

After cooking oatmeal, eat it or store it in the refrigerator relatively quickly before it goes bad. When keeping cooked oatmeal, allow it to cool for about 20 to 40 minutes and place it in the fridge. 

Cooked oatmeal stored in the refrigerator will last about five to seven days.

Most experts don’t recommend eating oatmeal that has been in the fridge for over five days. It is normal for cooked oatmeal to become more liquid after being stored in the refrigerator for a few days.

If oatmeal has been cooked and left to sit out for more than two hours, discard it, as bacterial growth can quickly cause it to spoil. After two hours, there is no saving it, as putting it in the fridge at this point is not recommended.

Oatmeal with blueberries, almonds and cinnamon.
Oatmeal with blueberries almonds and cinnamon

Can You Freeze Oatmeal?

All varieties of oatmeal can be frozen to prevent it from going bad. Follow these steps to freeze oatmeal:

  • Place cooked oatmeal into plastic freezer food storage bags or a plastic container with a lid.
  • Remove as much excess air as possible from the bag or container.
  • Date the bag or container for future reference.
  • Place the oatmeal into the freezer and store it up to six months.

The best way to defrost the frozen oatmeal is to move it into the refrigerator until thawed. If you don’t have the time to wait, reheat and thaw the oatmeal in the microwave.

What To Look for To Determine if Oatmeal Is Bad?

To determine if oatmeal is bad:

  • After opening a package of stored raw oats, check the inside of the bag to make sure there is no moisture accumulation. 
  • Smell the oatmeal for hints of rancidity and sour smell.
  • Check for discoloration.
  • Ensure oatmeal is not sticking together.

Since moisture can enter sealed bags, especially if there is a constant temperature fluctuation, any water would cause raw oatmeal to spoil rather quickly.

Next, smell the oatmeal, looking for any hints of rancidity. If oatmeal has a slightly sour smell, it is likely rancid. While it may be safe to eat, it isn’t ideal.

Look for any discoloration on the oats to determine if they have gone bad. If oatmeal looks darker or brighter than its usual color, it may be due to mold or insects. Oatmeal that has gone bad often clumps up, generally due to moisture accumulation. If this appears to be the case, assume the oatmeal is bad and discard it.

If it isn’t certain whether or not oatmeal has gone bad, always be cautious and discard it.

What Is the Proper Way To Store Oatmeal?

Oatmeal won’t go bad quickly if it is stored properly.

The proper way to store oatmeal is in a cool, dry place. It should be placed in a sealed container out of direct sunlight and away from heat.

A sealed container reduces oxidation because fresh air is unable to enter, increasing the lifespan significantly6. 

Additionally, a sealed container should keep out UV radiation known to damage food. A sealed container like a plastic bucket is ideal for keeping out critters. 

If shelflife is a concern, oatmeal stored in sealed mylar bags7 with oxygen-absorbing packets can last for up to 30 years. Check their current price on Amazon, Mylar Bags for food storage.

Another option is to seal oatmeal in #10 cans, ensuring nothing enters during storage.

Food like oatmeal can remain edible for up to 30 years after canning. Canned preservation is the ideal storage solution for a prepper or someone looking to stock large quantities of oats.

Depending on any other ingredients added into the oatmeal, like fruit and nuts, the storage times and methods may change8.

If you have any questions to ask me about this article don’t hesitate to comment below or email us. You can find an email on our contact page.

Read Next – More Food Storage Articles!

Storing Olive Oil 101

Plastic Food Storage Bag Safety Guide

The Ultimate Guide To Preserving And Storing Tofu

6 Cheeses That Can Be Left Unrefrigerated

The Complete Guide To Storing Extra Virgin Olive Oil

  1. Bob’s Red Mill: Oats and Oatmeal FAQs []
  2. Quaker: FAQs []
  3. USDA: How long can you store boxed dated foods? []
  4. National Center for Biotechnology Information: Nutritional advantages of oats and opportunities for its processing as value added foods – a review []
  5. University of Nebraska Lincoln: Food Storage []
  6. Michigan State University: Dry oatmeal needs careful handling []
  7. Extension Utah State University: A Guide to Food Storage []
  8. National Center for Home Food Preservation: Packaging and Storing Dried Foods []

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