How to Know when Oat Milk Is Bad

Co-authored by wikiHow Staff

Oat milk is a popular alternative to dairy milk because it's better for the environment and healthier in many ways. Oat milk has a shorter window of time that it's fresh—it usually lasts about 7-10 days in the fridge once it's been opened. After that point, inspect, smell, or taste the milk to see if it's spoiled. If not, drink up, but if so, toss it out!

Method 1

Method 1 of 2:

Checking for Spoiled Oat Milk

1
Check the expiration date on the oat milk container. Expiration dates are the first thing you should check when deciding whether your oat milk is still good or not. If the “Best By” or “Use By” date hasn’t passed yet, it’s likely that your oat milk is still safe to drink. If the date has passed, check other characteristics of the milk to ensure it’s still good.^{[1]
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- If your oat milk has been open for more than 10 days but the expiration date hasn't passed, it's best to still check whether it's spoiled or not before drinking it.
2
Pour a little bit of the milk in the sink to check the consistency. When oat milk is spoiled it becomes chunky and has a thicker consistency. To test this, pour a little bit of oat milk into the sink or in a bowl. If you notice that it’s lumpy and has an uneven texture instead of being smooth, it’s likely bad.^{[2]
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3
Look at the color of the milk to see if it has turned yellow. Spoiled oat milk has a yellow tint, darker than its natural, fresh color. If you notice that your milk doesn’t look the same color as it did when you bought or made it, it might be spoiled.^{[3]
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4
Smell the oat milk to check for a sour scent. Open the container of oat milk and smell it—if it smells slightly acidic or not fresh, it might have gone bad. When oat milk is way past its expiration date, it gives off a strong sour smell that's easily distinguishable from its normal smell.^{[4]
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- Smell your oat milk when it’s fresh so you know what it’s supposed to smell like.
5
Drink a little bit of oat milk to see if it tastes tart. If you’re still not sure whether the milk is spoiled or not, pour a small amount onto a spoon. Taste the oat milk and see if it tastes sour or not. If it does taste sour, spit it out and dispose of the milk.^{[5]
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- If the milk doesn’t taste different than usual, it’s likely still good.

Method 2

Method 2 of 2:

Storing Oat Milk

1
Store shelf-stable, store-bought oat milk in a cool, dry place. Most oat milk doesn’t need to be stored in the fridge if it’s unopened. Choose a cool, dry place to store your unopened oat milk such as a pantry or cabinet.^{[6]
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- Putting unopened oat milk straight in the fridge is okay too.
- Double check the label on the oat milk to ensure it’s safe to leave at room temperature.
2
Refrigerate oat milk right after opening it. Once you’ve broken the seal of the oat milk and opened it for the first time, store it in the fridge to keep it as fresh as possible. Otherwise, it will spoil quickly.^{[7]
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- After you use the oat milk, place it back in the fridge so it stays cold and fresh.
3
Use oat milk within 7-10 days of opening it. Unlike dairy milks, oat milk doesn’t last more than 10 days after it has been opened. Try to use up the container of oat milk within a week to 10 days to ensure you still have the freshest taste.^{[8]
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- If possible, plan on opening your oat milk when you know you’ll be able to drink it for the next week.
4
Store homemade oat milk for up to 5 days in the fridge. If you made your own oat milk instead of buying it at the store, place the milk in a sealed container like a glass jar with a lid on it. Store the milk for up to 5 days in the fridge to ensure it doesn’t go bad.^{[9]
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- If you notice your homemade oat milk start to separate, shake it gently before drinking it.
- Label the container with the date you made the oat milk so you know how long it will last.
5
Freeze oat milk to make it last longer. If you know you won’t be able to use all of your oat milk at once, place some of it in a freezer-safe container and put it in the freezer. Keep the oat milk in the freezer for up to 6 months and let it thaw in the fridge when it’s time to use it.^{[10]
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- Label the container with the date you put it in the freezer so you know how long it’s been in there.