How Long Does Oat Milk Last and How to Tell if It’s Bad?

Here’s everything you need to know about storage, shelf life, and spoilage of oat milk. After reading this article, you’ll know if you need to refrigerate it and how to tell if yours is bad.

You bought a carton of oat milk, drank a glass, and put the rest in the refrigerator. Now you’re wondering: how long does oat milk last in the fridge?

Or maybe yours has sat in the fridge for a couple of days already, and you’re not sure if it’s still okay to drink or not.

Sounds familiar? If so, you’re in the right place.

Let’s start by talking about whether oat milk requires refrigeration or not because it’s crucial to understand everything else.

Oat milk in hand

Does Oat Milk Need to Be Refrigerated?

Shelf-stable oat milk can sit at room temperature until you open it up. After opening, the leftovers require refrigeration. Refrigerated oat milk, on the other hand, requires refrigeration at all times.

In other words, you should store your oat milk the way it was in the grocery store (refrigerate it if it was in the refrigerated section) and place it in the fridge once you open the carton or bottle.

It works the same way for regular milk and other dairy-free milk alternatives such as almond milk, soy milk, coconut milk, and rice milk.

Now, you might be wondering why some bottles or cartons require constant refrigeration and if the shelf-stable ones are loaded with preservatives. Let’s cover that.

Refrigerated vs. Shelf-Stable Oat Milk

In almost all cases, the difference between shelf-stable and refrigerated oat milk is in packaging. Both types usually have the same ingredients and nutritional content.

Oatly explains it well on their website:

The shelf-stable cartons are packaged in an aseptic format that produces a totally 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).

Oatly

The cartons or bottles that require cold temperatures simply aren’t aseptically packaged. The rest is pretty much the same, which means you don’t have to worry about any crazy preservatives in the shelf-stable variety.

Because of that, you should always read the labels just to be sure you’re storing yours the way you should.

Some brands, like Califia Farms, try to make things a bit easier for their customers and use bottles for oat milk that requires refrigeration and cartons for the shelf-stable variety.

Also, not every brand offers the refrigerated variety, so check with your favorite one to learn more about their products.

Tip

If you’re using oat milk primarily as a coffee creamer, consider buying the Barista version of your favorite brand (if available). It tastes a bit more like regular milk and usually steams and froths better.

Long story short, neither type is better than the other, but the shelf-stable variety is undoubtedly a better option if you want to stock up.

Oat milk date on label
Oat milk date on label

How Long Can Oat Milk Sit Out?

According to USDA, if your half-open oat milk was left out at room temperature for more than 2 hours, you should discard it. That’s the official guideline for perishable food (which open oat milk is) that’s not refrigerated.

Of course, it’ll probably be fine if you leave it out for longer than that, but you never really know.

If you ever decide to bend that rule a bit, be smart about it. If that oat milk sits on the counter for 3 hours, it’s probably okay, but if you accidentally left it out overnight, it has to go.

Better safe than sorry.

Other Storage Practices

Besides keeping the carton in the right place, there are a few other basic oat milk storage practices to remember about.

Those are:

  • Always keep the carton sealed tight when not in use.
  • Don’t drink straight from the carton (unless you know you’re going to finish it).
  • Pour as much oat milk as you need into a glass a put the carton back in the fridge.
  • If your carton isn’t easily resealable, store the leftovers in a plastic container or a glass jar.
  • Shake the bottle or carton before pouring.
Glass of oat milk
Glass of oat milk

How Long Does Oat Milk Last?

Shelf-stable oat milk has a long shelf life and lasts for a few months past its best-by date. Refrigerated oat milk, on the other hand, keeps only for a week or so past its date.

Once you open a carton or bottle, you should finish it within 7 to 10 days, depending on the brand.

That’s the gist of it.

PantryFridge
Oat milk (shelf-stable)Best-by + 3 – 6 months
Oat milk (chilled carton)Sell-by + 5 – 7 days
Oat milk (opened)5 – 10 days

Expired Oat Milk

As you already know, there are two types of oat milk available on the market: the shelf-stable and one that’s sold refrigerated. And the most important difference between the two, besides how you store each, is their shelf life.

Shelf-stable oat milk typically has a shelf life of 6 to 12+ months and easily keeps for a couple of months past its date, as long as it’s unopened. The refrigerated variety comes with a use-by date that’s only a couple of weeks from the production and keeps for only a week or so after the printed date.

That means that whether your expired oat milk might be okay to use or not depends on which variety we’re talking about.

If it’s the shelf-stable, chances are it’ll be fine even if it’s half a year after its date. So unless you’re not comfortable with using “expired” oat milk, feel free to open it up, check for signs of spoilage (more on that later), and use it if there are none.

For refrigerated oat milk, I’d toss it if it’s more than 7 to 10 days past its date, just to be safe. You probably do the same thing for most dairy products.

Coffe with oat milk
Coffee with oat milk

After Opening

Oat milk typically keeps for about 7 to 10 days after first opening the carton or bottle. The recommendations vary a bit between brands, but if you finish yours within 4 to 5 days, you should be in the clear no matter the brand you choose.

(The 4 to 5 days of storage recommendation falls in line with the 4 to 5 days rule for perishable leftovers.)

Some producers, like Tōats, suggest shorter storage times (4 to 7 days in this case), while others, like Oatsome, go with more relaxed guidelines of 7 to 10 days to finish the carton.

The truth is, it’s mainly about the quality of the product, and probably all various oat milks available should taste quite okay around the 7-day mark.

Tip

Write the day you opened the carton on the bottle to keep track of how long it’s open easily.

Last but not least, if yours is open for like two weeks or so, discard it even if it doesn’t show any signs of spoilage. Better safe than sorry.

Alpro oat milk container
Alpro oat milk container

How to Tell if Oat Milk Is Bad?

Here’s how you check if your oat milk is okay:

  1. Check how long it’s opened. If it’s more than two weeks, discard it no matter what.
  2. Open the bottle or carton and give it a sniff. If it smells moldy, off, or sour, discard it.
  3. Give it a shake and pour some in a glass.
  4. Check the consistency and color. There might be some minor changes, but nothing significant. If it’s slimy, completely separated, or anything else like that, it has to go. Same thing if you notice any microbial growth or anything else that shouldn’t be there.
  5. Give the liquid a taste. Assuming that everything is okay up until now, it’s time for the flavor check. Oat milk is supposed to be a bit nuttier than cow’s milk and with a hint of oats. Many brands also taste quite sweet, even if there aren’t any artificial sweeteners or sugar added. If it’s sour, it’s time for it to go.
Oat milk in a glass: closeup
Oat milk in a glass: closeup

If your oat milk has passed every single test described above, chances are it’s fine to use.

As usual, if you’re not 100% sure it’s safe to drink, discard it. It’s better to err on the side of caution and open a new one instead.

Warning

Oat milks from various brands taste differently. If you bought a different brand than what you’re used to, don’t be surprised that the flavor isn’t quite the same. Or that you suddenly don’t like it in your coffee.