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Does Oat Milk Go Bad?

Oat milk is something that many people now choose instead of lactose-based milk, to enjoy as a dairy milk substitute.

Not all oat milk tastes the same, so it can be a matter of trial and error before you find the brand of oat milk that you enjoy the most.

Does oat milk go bad? Shelf-stable oat milk comes in packaging that does not need to be kept in the fridge while it is unopened.

Other brands of oat milk are found in the chiller cabinet at the supermarket, and are meant to be kept refrigerated whether they have been opened or not to stop them from going bad. 

Does Oat Milk Go Bad?

Oat Milk

Most types of oat milk do go bad between 7-10 days after opening, but this varies between brands, so always check the label. Oat milk will go bad after a few hours, once opened, if it is not stored in the fridge.

Oat milk that is designed to be kept unrefrigerated till opening will go bad if it is not used by its best before date.

Oat milk bought chilled will have a use-by date and will go bad if it is not used before that time, even if it is kept unopened and stored in the fridge. 

The best idea is to treat opened oat milk in the same way you would treat regular milk, to prevent it from going bad.

The good news is that there are ways to store and keep oat milk that can prevent it from going bad too quickly, so that you can keep your oat milk for as long as possible.

 When Does Oat Milk Go Bad?

The golden rule here is to err on the side of caution. If you think your oat milk may have gone bad, throw it away and use a new carton or bottle.

Some shelf-stable oat milk might be okay a few months past the date on the label, but it’s always best to check to see if your oat milk has gone bad by doing the following:

  • Make sure your oat milk hasn’t been open for more than 7-10 days.
  • Smell it. If it smells off, it probably is. It might smell sour or musty or not quite right, which is a sign that you need to bin it.
  • Shake well and pour some into a glass. Does it look like it usually does? If it is separated, has a thicker consistency, or looks slimy or separated, discard it.
  • Taste it to see if it smells and looks okay. If it tastes a little sour or it doesn’t taste like it usually does, throw it away.

RELATED: A Comprehensive Review Of Oat Milk Dangers!

How Do I Stop Oat Milk From Going Bad?

Does oat milk go bad if it’s not properly stored? It does, but here are our ideas for making sure your oat milk lasts as long as possible:  

  • If you are using shelf-stable oat milk, store it in a cool, dark place until you open it, then move it to the refrigerator.
  • Make sure that you do not leave the oat milk out of the fridge, once it has been opened.
  • Make sure the lid of your oat milk is tightly closed when you’re not using it.
  • Always shake your oat milk well, before using it.
  • Don’t drink your oat milk directly from the carton, to prevent the spread of germs and bacteria.
  • Always check the label before use and make sure your oat milk is on date.

How To Store Oat Milk To Prevent It From Going Bad

Oat Milk

1. Always make sure that you follow the instructions on the packaging of your oat milk, to ensure the longest shelf life.

If you bought your oat milk from a chiller cabinet, ensure it remains chilled and stored in the fridge as soon as you can (don’t leave it in your car for a few hours). 

2. Even shelf-stable oat milk can go bad. If it is kept on a worktop or shelf before opening, try and ensure it is in a space that is cool and dark to prevent it from getting too warm.

This will ensure that it lasts as long as possible before you need it. Shelf-stable oat milk can last for as long as 6-9 months before opening, if you store it correctly.

According to some sources, it can even last much longer – years, in fact, but be sure to follow our tests before you use your oat milk, if it has passed its use-by date. 

3. Once opened, always keep your oat milk in the fridge, at a temperature of between 37 to 40 degrees Fahrenheit. Treat it in the same way you would treat regular cow’s milk or other dairy products.

4. Make sure you always close the lid fully after you’ve used it.

5. If you can’t keep your oat milk in its original bottle or carton, store it in a tightly sealed container in the fridge. 

6. Respect the label’s guidelines on how long to keep your oat milk before it goes bad. It might last a little longer than they suggest, but don’t exceed the bounds of common sense.

Does Oat Milk Go Bad If It’s Been Frozen? 

Freezing oat milk is a great way to store oat milk that has been opened, to prevent it from going bad.

Freezing does change the texture of your oat milk, so it can appear to have gone bad, but it will be perfectly fine to use for smoothies or in cooking. It will last in the freezer for up to six months, before it goes bad.

The Challenges Of Knowing If Your Oat Milk Has Gone Bad

Oat Milk

If you’ve bought a new brand of oat milk from your usual one, it may taste different to your regular brand.

There can be a lot of taste differences, even between two brands of shelf-stable oat milk. Some oat milk brands are sweetened; some are less so.

There are also specialist types of oat milk, like barista style, that are designed for use in coffee. All of those things can mean a large difference in quality and taste between the different types of oat milk. 

These factors can all affect how your oat milk tastes when it’s fresh, which can make it more challenging to know if your oat milk has gone bad.

Frequently Asked Questions

 Is There A Downside To Oat Milk?

If you are suffering from celiac disease then oat milk won’t be a good choice to have since it comes with high carbohydrates and consists a very higher amount of calories.

Out of many plant based milks it has the higher calories and carbohydrates.

Is Oat Milk Bad For Your Gut?

According to a study in 2017, beta content gluten help in promoting gut. Since beta gluten is connected to gut health and oat milk is good source of it so it won’t harm your gut in any way.

Is Oat Milk Or Almond Better?

There is little to no difference between Oat and Almond milk in terms of nutritional content. However, they do differ slightly. Although almond milk is high in fat and calcium, oat milk contains more carbohydrates and iron.

Does Oak Milk Go Bad?

How To Store Oat Milk To Prevent It From Going Bad

Oat milk is an excellent dairy alternative because it contains fewer calories and nutrients than regular cow milk.


  • Oat Milk


  • Fridge
  • Sealed Container


    1. Follow Instructions: Always follow the instructions on the packaging to ensure the most extended shelf life, and store it in the fridge.
    2. Use before the date: For shelf-stable milk to last longer, keep it in a dark and cool place. If stored correctly, it will last up to 6-9 months.
    3. Store in Fridge: Once you have opened the carton of oat milk, keep it in the fridge the same way you keep your regular milk.
    4. Close the lid: If you have opened the bottle or carton of your oat milk, close the cap properly after using it to make it last longer.
    5. Store in a tightly sealed container: If you cannot keep oat milk in its original bottle or container, then transferring it to a tightly closed container works best.
    6. Check the label: The best time to use your oat milk is to follow the instructions on the label. It might last a little longer, but don’t go overboard and use your common sense too.
Jess Smith

Wednesday 7th of June 2023

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