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Does Oat Milk Go Bad?

Does Oat Milk Go Bad?

There are so many milk alternatives out there these days. Thankfully, it gives those of us with dairy sensitivities the ability to enjoy things from breakfast cereal to milkshakes without the added stomachache. However, with all the new variations of dairy-free milk products, like oat milk, it can be trickier than taking a whiff of the milk to know it has spoiled.

Depending on the brand, oat milk can go bad within 7-10 days after opening the carton. However, you can store shelf-stable oat milk in a cool, dry place for much longer. The label usually mentions a nine-month shelf life, but when stored properly, oat milk can survive for around 3 to 5 years.

Those are some varying lengths of time when considering opened versus unopened containers. So, let’s discuss oat milk nuances more in-depth because there are more things to bear in mind when wondering if your milk has gone past its due date.

How to Tell If Oat Milk Has Gone Bad

While it’s important to follow the suggestions on the labels, usually, oat milk is still okay to drink for a day or two after its recommended expiration date after opening. But what should you look out for?

Like dairy milk, be sure to check oat milk’s smell, appearance, and taste to determine if it has gone bad.

Smell the Oat Milk

Open the container and slosh the milk around while sniffing at the opening. Non-dairy milk products do not have the same stench as spoiled dairy milk, so you may not smell anything bad. It should have a pleasant, even sweet, scent. If it smells sour or bitter, that’s not a good sign.

Look at the Oat Milk’s Appearance

Check the color. Unless it is flavored oat milk, the color should be a creamy white, almost light brown. Look inside the container and around the lid. If there is any mold growing, throw it out. Though this stage takes longer, mold likes to grow in liquid and moist areas.

Finally, pour some of the liquid out to see if it has become lumpy. Now, as with most beverages, there is often a separation, so be sure you have given it a good shake. Oat milk should be smooth. If you see lumps or feel sliminess or feel that it is clumping together in the carton, you will know it has gone bad.

If you’re still questioning, give the milk a sip.

Does Oat Milk Need to Be Refrigerated?

Whether oat milk needs to be refrigerated depends on how you bought it, to begin with. Many brands are found on the shelf, not refrigerated, and they can be left on the shelf when you get home until you open them. At that time, they need to be kept continually in the refrigerator until you have finished the carton.

Other oat milk brands are bought in the refrigerated section, and these do need to be kept refrigerated when you arrive home. Then, once the seal is broken, it is recommended that you finish it after a week. This ensures bacteria do not have time to grow.

You want your milk to be fresh because, over time, the healthy vitamins and minerals die away. You can drink oat milk that has expired as long as it hasn’t spoiled. Expired just means it’s past its recommended sell-by date. Spoiled implies bacteria growth and mold spores have entered in, and it is not safe to consume.

If the oat milk is mixed in with coffee, it can actually go bad after 3 days due to the acidity of the coffee.

What If I Left My Milk Out?

If oat milk is accidentally left out of the fridge for more than 2 hours, consider the temperature and air exposure as well before throwing it away. Perhaps it was a hot day, and the milk was left in the heat. It will spoil much faster than in a cool spot. Think about if the lid was secured as well. Keeping the liquid airtight will better protect it, but return the milk to the refrigerator as quickly as possible.

Why Are Some Brands Refrigerated and Others Aren’t?

Shelf-stable oat milk has different packaging requirements that more effectively protect it from outside conditions than the kind you pick up in the refrigerated section. The cartons in the refrigerated section are much thinner. These liquids are exposed to higher levels of oxidation. Meaning, to keep bacteria away, they need to be consumed faster and kept under a certain temperature.


When at the store, keep in mind that oat milk does go bad eventually. Depending on packaging and storage, the difference between good oat milk and bad oat milk varies greatly. But fear not! Your eyes, nose, and mouth are terrific indicators as to whether or not your milk is past its spoiled state.