How Long Can Oat Milk Sit Out – [A Complete Guide]

Generally, oat milk is made by extracting the plant material from the entire oats and mixing it with water. There are several kinds of oatmeal milk, including sweetened, unsweetened, vanilla, and chocolate. Oatmeal milk has a mild taste and is creamy to the touch.

How long can oat milk sit out?

You can keep Shelf-stable oat milk at room temperature until it is opened. If your half-opened oat milk has been left out at room temperature for more than 2 hours, the USDA recommends discarding it. The leftovers must be refrigerated after they have been opened. On the other hand, refrigerated oat milk must be kept refrigerated at all times.

Oat milk is a type of milk that is made from oats. It is a dairy-free milk alternative and is a good choice for people who are lactose intolerant or have allergies to dairy. Oat milk is a good source of vitamins and minerals, and it can be a good alternative to cow’s milk for people who are looking for a non-dairy milk option. Oat milk can sit out unopened for up to two hours.

If you’re curious to know everything about oat milk storage, shelf life, and spoiling: after reading this article, you’ll see if you need to refrigerate it and how to detect if yours is bad. We have some interesting guides on what to look for. 

How Long Can Oat Milk Sit Out

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Does Oat Milk Go Bad If Left Out?

According to manufacturer recommendations, the packaging of shelf-stable oat milk differs from that of refrigerated oat milk. Although the nutrients and ingredients in oat milk are the same in both forms, they should be refrigerated and consumed within 7 to 10 days after opening.

That’s the official rule for perishable food that isn’t refrigerated (like open oat milk Unopened oat milk is sold in the supermarket’s dry goods section rather than refrigerated. 

There are many benefits of oat milk, including being a healthy and good source of nutrition and fiber and containing plant-based proteins in high quantities. Additionally, it promotes a healthy digestive system and weight loss since low fat, low sugar, and low calorie. 

Though it’s not as healthy as cow’s milk, oat milk tastes much like cow’s milk; its consistency is thick and sweet. Let’s get into the further details related to oat milk like storage, expiry, taste change, and more. 

How Long Can Oat Milk Sit Out at Room Temperature? 

Oat milk can sit out at room temperature for only two hours. Of course, if you keep it out for longer than that, it’ll probably be fine, but you never know. 

If you do decide to break that rule, do it with caution. If you leave the oat milk out on the counter for 3 hours, it should be fine, but it must be discarded if you leave it out overnight. 

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How Do You Know If Oat Milk Has Gone Bad?

To determine whether your oat milk is okay or not, here are some points you can check, 

  • If oat milk is opened for more than two weeks, discard it. 
  • Please give it a sniff once you’ve opened the bottle or carton. Throw it out if it smells rotten, foul, or sour. 
  • Examine the color and consistency. There may be some minor adjustments, but nothing major. It has to go if it’s slimy, entirely detached, or anything else like that. Do the same thing if you find any microbial growth or anything else that shouldn’t be there. 
  • Take a sip of the drink and give it a try. Assuming everything has gone well so far, it’s time for the flavor test. Oat milk is said to have a nuttier flavor than cow’s milk with a hint of oats. Even if there are no artificial sweeteners or sugar added, many products taste relatively sweet. It’s time to let it go if it’s sour.

Is It Safe to Drink Oat Milk Left Out Overnight? 

It depends on the room temperature since the US Food and Drug Administration recommends discarding milk that has been out of the refrigerator for more than two hours. You might be able to consume the oat milk if the room temperature is cool and it has only been a little over two hours. 

In cool temperatures, the chances of spoliation of oat milk are low, while in hot temperatures, if the oat milk is not stored in the refrigerator, it can be spoiled easily, so it’s not safe to drink the oat milk left out overnight.

Does Oat Milk Need to Be Refrigerated?

It is generally recommended that oat milk be refrigerated, in order to extend its shelf life. However, some brands of oat milk are shelf-stable and do not need to be refrigerated until after they are opened.

Does Oat Milk Get Bad If Not Refrigerated? 

You can keep a shelf-stable store-bought oat milk bottle or carton at room temperature until it expires or for a few days after it expires if you keep it unopened. Depending on the packaging, there are shelf-stable varieties and refrigerated varieties of oat milk. Both types usually have the same qualities and nutrition.

The shelf-stable cartons are packaged in an aseptic format that produces a sterile environment, resulting in a product with a longer shelf life and no need for refrigeration (until it’s been opened for the first time, that is). 


How Long Can Oat Milk Sit Out Unopened?

Unopened oat milk can sit out for up to two days. If you bought packaged oat milk from the market, it is recommended that you refrigerate it rather than leave it at room temperature. Room temperature is not suitable for storing the oat milk for an extended period of time.

How Long Can Oat Milk Be Left Out of Fridge?

If you do not refrigerate, then freshly squeezed oat milk can be left out at room temperature for up to 2 hours or 3 hours at most. Shelf-stable oat milk will keep for at least a few months beyond its expiration date. 

You can keep shelf-stable oat milk in a closed bottle or carton at room temperature for up to the expiration date or a few days after the expiration date if it has not been opened.

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What Does Bad Oat Milk Taste Like?

Spoiled oat milk tastes really bad. 

It tastes sour and smelly and you might feel the taste change from the original taste. It’s better not to drink the milk if you feel any difference having it.

What to Do with Expired Oat Milk?

It’s essential to discard any outdated oat milk right away because it could harm you. The shelf-stable and refrigerated varieties of oat milk are available on the market; apart from how you store them, the most significant difference between the two is their shelf life.

Shelf-stable oat milk has a shelf life of 6 to 12 months and can easily be kept for a few months past its expiration date if kept unopened. The refrigerated variant has a use-by date only a few weeks after production and only lasts about a week after the printed date. 

So depending on which type of oat milk we are talking about, it might or might not be safe. 

A sip or two can not be harmful; however, consuming a moderate quantity can cause you to suffer from food poisoning, vomiting, nausea, diarrhea, and stomach pain. It’s better to be safe than sorry. 


I would say that oat milk is a great healthy alternative to dairy milk. One vegan and looking for a healthy alternative to dairy milk should try oat milk; it has excellent nutritional values. Still, keeping in mind the difference between shelf-stable and refrigerated ones, some other things need consideration, like the storage method and temperature.

The most important thing is how long oat milk can sit out. We have discussed almost all aspects of this. I hope you find it helpful. I will suggest you give oat milk a try and enjoy it.

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