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How to Store Oats

A photo collage on how to store an oat.
  • Oats are an affordable staple food that can last for a very long time if you know how to store it correctly and keep it from going rancid or moldy
  • You can learn how to increase the shelf-life of raw oats as well as cooked oats 
  • In this article, you will find out which containers are best for storing oats for long-term or short-term use 

What are oats? 

Oats are a versatile and highly nutritious staple food that has been cultivated for many years. Oats (Avena sativa) are whole grains typically grown in regions with cool, moist climates. They are grown from seeds that take between 6-10 weeks to germinate. It can take up to 6 months for the oats to be ready to harvest. 

Oats are very high in dietary fiber and contain vitamins and minerals like niacin, vitamin B6, riboflavin, folate, magnesium, iron, and zinc. They are an excellent source of protein and serve as potent antioxidants in the body. 

Types of oats 

There are many types of oats, with each type undergoing different forms of processing before it reaches our pantries. The type of oats will determine how it is to be stored to maintain freshness and nutritional value for as long as possible.  

Whole oat groats

A plate of whole organic oat groats with wooden scooper.

This is the least processed type of oat grain. The groats go through a cleaning process where the hull is removed, but the germ, endosperm, and bran are left intact. The oat bran has the most health benefits and the highest fiber content. 

Steel-cut oats

This is a wooden bowl of raw organic steel cut oats.

Often referred to as Irish oats, steel-cut oats are oat groats chopped into smaller pieces with a steel blade. They are chewier than whole oat groats and have a nutty taste.    

Rolled oats

This is a wood bowl full of rolled oats and wooden scooper on the side.

This is sometimes referred to as “old-fashioned oats” and remains one of the most popular types of oats. The whole oat groats are steamed and flattened into flakes by rolling them between steel rollers. Some flakes may be thicker than others, but all have the same nutritional benefits. 

Scottish oats

This is a bunch of Scottish oats on a white surface.

They are stone-ground oats that are made by grinding whole oat groats. Scottish oats have a creamy, fine texture and are considered the best oats to use in porridge. 

Quick oats

This is a bowl of quick oats and a wooden spoon on a marble counter.

This is basically rolled oats that are steamed longer, chopped smaller, and rolled into thinner flakes than normal rolled oats. A larger surface area means they absorb water quickly and therefore have a much shorter cooking time.

Instant oats 

This is a bowl of instant oatmeal for breakfast.

These oats undergo the same processing as quick oats, with an added process of being pre-cooked before they are packaged. Instant oats usually require a quick soak in hot water and often don’t even need to be microwaved. 

Oat flour

These are wholemeal oat flour with oatmeal on a rustic setting.

The bran, germ, and endosperm from whole-grain oat groats are ground until they produce a fine, tan-colored flour product. Oat flour has a nutty taste and is used in baking or as a thickening agent in soups and stews. 

Oat bran

This is a mound of oat bran in a wooden bowl.

This is the bran section that makes up the outer covering of a whole oat groat. It is very high in fiber and carries many health benefits. You can add oat bran flakes to foods like muffins, pancakes, bread, and even smoothies to increase the fiber content and add a bit of nutrition. 

How To Store Oats 

Oats are considered to be a non-perishable staple food item. Oats must be stored in a way that will prevent moisture and pests from getting in. The way you store them will depend on whether they are cooked or uncooked and on the type of processing they have undergone. 

Keep them stored in the original packaging 

This is a box of oat granola cereal with 30% less fat.

If you have a few months’ supplies of oats that you bought for everyday use in cereals or smoothies, you can keep them in their original packaging if it seals properly. Rolled oats that are kept in this packaging can last for 18-24 months. Do not keep oats in the original packaging for more than two years, especially if opened. 

Use air-tight plastic containers to store bulk oats 

Long-term storage is required when you have a bulk supply of oats that needs to last for more than two years. The best way to keep your uncooked oats from going rancid is to store them in air-tight plastic containers like a bucket in a dry, cool place like the pantry. This applies to all types of oats, including oat flour and oat bran. 

Use resealable plastic bags 

Oat groat in a resealable bag and bowl with a bottle of fresh milk.

If you have a package of oatmeal that has been opened and that should last a few months, you could store it in a tightly covered resealable freezer bag. Make sure you keep the bag of oats in a dark, dry place like the pantry, and do not keep it for longer than one year if not consumed. 

Use oxygen absorbers to increase shelf life

These are small packs of oxygen absorbers.

These sachets contain an iron powder that becomes iron oxide when exposed to oxygen. Oxygen absorbers suck unwanted oxygen out of storage containers and are must-haves for the long-term storage of food. They can be used in rigid containers or Mylar bags. 

The size of the oxygen absorber depends on the size of the container/bag and also what type of oats you are storing. Smaller containers/bags need fewer oxygen absorbers than larger containers/bags. Finer oats like oat flour need fewer oxygen absorbers than denser grains like rolled oats, oat bran, and oat groats. 

It is recommended to follow the manufacturer’s instructions when choosing how many oxygen absorbers to use. 

Store the oats in mason jars 

This is a woman keeping oats in jars with labels.

Mason jars are a good option for storing oats. You can also add labels to the jars when you have different types of oats, e.g., oat bran, oat flour, and rolled oats. Each can have its own jar. Make sure to press down on the oats before you seal the jar to ensure most oxygen is out. You can also add a few oxygen absorbers to the jars to ensure the oats stay fresh for longer. 

Use a #10 can store small batches of oats 

These cans are a great way to store oats in the long term. These cans can usually take about 2,5 pounds of oats. Keep the cans sealed and place them in a cool, dry, and dark place. Oats stored in this way can last up to 30 years if unopened. If opened, it is recommended to consume the oats within 9-12 months. 

Keep oats in the refrigerator

This is a jar of overnight oats with fruits, nuts and carrots.

If you don’t have space in the pantry or live in a very hot and humid region, it may be best to keep the oats stored in the refrigerator. Make sure they are in air-tight containers or bags to prevent moisture from entering. Oats kept in the fridge will stay fresh for longer than two years. 

Store oats in the freezer 

Although it isn’t necessary to freeze oats, you can freeze them. Freezing oats will not alter their nutritional value and will ensure they stay fresh for longer. Freezing oats has the extra benefit of killing off any insects or eggs in the oats. Frozen oats can be defrosted and cooked in the microwave or on the stove at any time. 

How to store cooked oatmeal

This is a bowl of oatmeal porridge with strawberries and nuts.

The refrigerator or freezer is the best way to store cooked oatmeal, whether it be whole oat groats, steel-cut oats, or rolled oats. Room temperature or humid conditions may encourage bacterial growth and mold formation on your oats.  

You can keep a bowl of oatmeal porridge in the fridge for 3-6 days. It is recommended to seal the bowl with plastic wrap if you are making overnight oats. You can also split a larger bowl of oats into smaller portions kept in smaller, air-tight plastic bags.

Freezing cooked oats is the best and safest storage option if you are not planning on consuming the oats within the next week or two. Resealable heavy-duty freezer bags are the best for long-term storage. Make sure to compress the bag before sealing to remove the excess air and so that your oats don’t take up a lot of space in your freezer. Do not freeze cooked oats for longer than six months. 


What causes oats to go bad? 

If humidity is high and oats aren’t sealed properly, moisture can cause oats to turn rancid. Warm temperatures may cause moisture to condensate inside the oats’ packaging and cause mold to grow inside the oats. Exposure to light and oxygen can cause oats to go bad quicker due to oxidation processes. Oats that aren’t stored properly can also harbor insect eggs and be a breeding ground for meal moths. 

What are signs that my oats may have gone rancid? 

  • Textural or color changes. Changes in the texture or color of the oats are a sure sign that something’s off. If you sense a discoloration or texture that’s different from what you’re used to, take precautions before using the oats. 
  • Mold. Oats that have gone rancid may have mold growing in them, usually due to moisture. The mold is usually very noticeable as it grows on top of the oats. Throw your oats away if you see any mold growth. 
  • Smell. If your oats suddenly smell funky or moldy, they may be going off. Check for visible signs in the color and texture and possible mold that may be causing the smell. 

Which type of oats can be stored the longest? 

More stabilized forms of oats have a longer shelf life. Instant oats, steel-cut oats, and rolled oats undergo steaming and flattening processes that stabilize the oils in the grains, so you can store these types of oats the longest. 

Which type of oats has the shortest shelf life? 

Oat flour has a shorter shelf life than other types of oats due to its fine texture and larger surface area. Oat bran has the shortest shelf life because the many natural oils make it less stable. Oat bran is not great for long-term storage, even when stored correctly and with oxygen absorbers.  


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