Will Oat Milk Go Bad If Left Out

Will Oat Milk Go Bad If Left Out? Preserving Your Beverage

Last Updated on February 18, 2024 by Shari Mason

Oat milk, a favored substitute for dairy, blesses numerous homes with its smooth texture and mild flavor. However, similar to a variety of drinks, it possesses its own set of storage instructions.

A common query is whether oat milk can endure outside the fridge.

I always have oat milk in my fridge, and so, drawing from my everyday experience, let’s delve into the shelf life of oat milk and its behavior at room temperature.

Can Oat Milk Be Left At Room Temperature? 

Pouring Oat Milk on a Glass

Yes, when unopened, and if it’s the shelf-stable variety, oat milk [1] can be stored at room temperature. Manufacturers design these versions for longer shelf lives outside the fridge. 

“There are those who love to get dirty and fix things. They drink coffee at dawn, beer after work. And those who stay clean, just appreciate things. At breakfast they have milk and juice at night. There are those who do both, they drink tea.”

– Gary Snyder, American Poet

However, once opened, oat milk should be refrigerated and consumed within a specific timeframe, typically 7-10 days, to ensure freshness and prevent spoilage. 

Always check the label for specific storage instructions, as some oat milk variants require refrigeration from the outset.

Also Read:

Can You Freeze Oat Milk?

Yes, oat milk can be frozen, though it’s essential to understand that the texture and consistency might change upon thawing.

Freezing oat milk is a practical solution if you’ve purchased it in bulk or will only consume it after its expiration date. 

Before freezing, ensure some space in the container, as liquids expand when frozen. To use after freezing, give the container a good shake or stir to mix any separated components. 

Remember that while freezing extends shelf life, consuming the oat milk soon after thawing for optimal flavor and texture is best.

Signs That It Has Gone Bad

Woman Holding Bottle of Oat Milk
  1. Off-putting Smell: Fresh oat milk has a mild, naturally sweet scent. If it starts to smell sour or has a rancid odor, it’s time to toss it.
  2. Change in Taste: If the oat milk tastes sour or off, it’s likely gone bad.
  3. Separation: While some natural separation can occur in oat milk, if you notice thick clumps or chunks, especially after shaking, it’s a sign of spoilage.
  4. Mold Growth: Any visible mold floating in the milk or around the rim or cap of the container is a clear sign of spoilage.
  5. Swollen or Leaking Container: A sealed container of oat milk bulges or leaks can indicate bacterial activity and gas production. Avoid consuming the contents.
  6. Altered Texture: If the oat milk becomes overly thick, slimy, or gooey, it’s unsafe to drink.
  7. Expiration Date: While products can sometimes last beyond their printed date, checking the expiration date is always a good idea. It’s best to err on caution and discard it if it’s long past.
  8. Discoloration: Any discoloration, such as a yellowish hue, can indicate spoilage.

“Oat milk’s charm lies in its freshness; leave it out, and time steals its grace.”

– Eat Pallet Restaurant & Food Advice

Tips On How To Store Oat Milk

  1. Keep it Refrigerated:
    • Upon Purchase: Ensure that the oat milk is refrigerated when you buy it if it’s the refrigerated variety. Some oat milk is sold unrefrigerated but should be refrigerated once opened.
    • After Opening: Always return oat milk to the fridge promptly after using it. This helps maintain its freshness and prevents the growth of harmful bacteria [2].
  2. Tightly Seal the Container:
    • After each use, make sure the cap is tightly sealed. This prevents the introduction of air and contaminants, which can speed up spoilage.
  3. Store Away from Light:
    • Exposure to light can degrade the quality of oat milk. Store it in its original opaque container, preferably in the back of the fridge where it’s cooler and darker.
  4. Avoid Cross-Contamination:
    • Use a clean glass or cup every time you pour oat milk. Don’t drink directly from the container, as introducing saliva can speed up spoiling.
  5. Consider Transfer to a Glass Container:
    • If you’ve opened a large container of oat milk and won’t finish it quickly, consider transferring a portion to a smaller glass container. This limits the amount of air exposure each time you open it.
  6. Monitor Expiry Dates:
    • Always check the expiration date when buying and periodically as you use the product. Remember that once opened, oat milk usually remains fresh for 7-10 days, regardless of the printed expiration date.
  7. Freezing is an Option:
    • You can freeze oat milk if you want to extend the shelf life. However, the texture might change slightly upon thawing, making it better suited for cooking or baking than direct consumption.
  8. Store Upright:
    • Ensure the oat milk container stands upright in the fridge to prevent leaks and contamination.
  9. Avoid Storing Near Strong Odor Foods:
    • Like other alternatives, oat milk can absorb flavors and odors from surrounding foods, so avoid placing it near strong-smelling items like onions or garlic.
  10. Rotate Stock:
    • If you buy oat milk in bulk, use the first-in-first-out method. This ensures that the oldest carton is used first, reducing the chances of spoilage.


u003cstrongu003eDoes oat milk need to be refrigerated if not opened?u003c/strongu003e

No, if oat milk is sold unrefrigerated (shelf-stable packaging), it does not need to be refrigerated until it is opened. Always check the label for specific storage instructions.

u003cstrongu003eCan bacteria grow in oat milk?u003c/strongu003e

Yes, bacteria can grow in oat milk, especially if it is improperly stored or left at room temperature for extended periods after opening. Always refrigerate after opening and consume within the recommended timeframe.

In Conclusion

Like many other plant-based milks, oat milk is susceptible to spoilage when exposed to warm temperatures for prolonged periods. 

It’s essential to ensure proper storage to maintain freshness and prevent bacterial growth, whether opened or unopened. 

Always be cautious and check for signs of spoilage before consumption. For the best experience, store your oat milk in a cool environment and always refrigerate after opening. 

Safe storage practices are crucial to enjoying its rich flavor and nutritional benefits.


Shari Mason

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