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How Can You Tell If Oat Milk Has Gone Bad?

How Can You Tell If Oat Milk Has Gone Bad?

Oat milk has a shelf life of about two weeks, but you can tell if it’s gone bad before then. Oat milk can go bad if exposed to heat or light for too long. So, if you see any color changes or it develops an off-smell or taste, toss the oat milk and get a new bottle.

Oat milk is a popular alternative to regular dairy but can also go bad. If you’ve noticed yours has expired or if its flavor has changed, there are some things you can do to determine if it’s still safe to drink.

However, like all other foods, oat milk does have an expiration date. If you’re unsure about whether your oat milk is still good or not, there are several ways you can test it out. 

Reasons Oat Milk Goes Bad

Oat Milk

There are many reasons why oat milk goes bad, including:

Left At Room Temperature For Too Long

When it is left at room temperature for too long, the oat milk can become contaminated with germs that can cause food poisoning. The problem with oat milk that has been left out too long is that it will begin to ferment.

The fermentation process changes the flavor of oat milk and turns it into something that tastes more like sour cream than oat milk.

If you keep your oat milk in the fridge, the chances are good that you’ll have it around for a while. But if you leave it out on the counter or in your pantry after opening it, it’s likely to go bad before you know it.

Oat Milk Was Not Properly Stored

Oat milk can go bad if it is not properly stored. This can happen if the oat milk is left in a warm and wet environment, even if it has not been opened.

It is best to store unopened oat milk in the refrigerator if possible. If you live in a warm and humid climate, you may want to keep your oat milk in an airtight container on the countertop rather than in the refrigerator.

When storing your oat milk, make sure that it is not exposed to any open containers of water or liquid. 

Often, oat milk does not need to be refrigerated until it’s been opened. However, you should store oat milk in cool conditions.

Oat Milk Has Been Exposed To Air

Oat milk contains a lot of air. When you open the container, you will notice that there are a lot of bubbles on the surface.

The oat milk is exposed to air when you open the container and pour some into your cup. This can cause it to go bad quickly if it is not refrigerated properly or stored in an airtight container after opening.

Oat Milk Is Expired

Oat milk is an excellent and healthy alternative to dairy milk, but it doesn’t keep forever. If you don’t use up the container before the date on the label, you’ll need to throw it out. The milk can go bad in two ways: through microbial growth and oxidation.

Microbial growth happens when bacteria and yeast grow inside the container, which makes it smell sour, turn yellow, or develop a layer of mold on top. Oxidation happens when the milk picks up oxygen from the air and then turns brown.

RELATED: What Are The Health Benefits of Oat Milk?

What Will Happen If You Consume Oat Milk That Has Gone Bad?

Oat milk is a popular alternative to dairy milk, as it is plant-based and contains no cholesterol. If you consume oat milk that has gone bad, it can cause a number of negative health effects, including:


Many people associate nausea with food poisoning because it is usually the immediate reaction to food poisoning.

Nausea occurs when the stomach’s lining becomes irritated and causes food to move through the digestive tract at an accelerated rate, which causes discomfort. In some cases, nausea is accompanied by vomiting, sweating, and diarrhea.

If you consume oat milk that has gone bad, you may experience nausea along with other symptoms such as gas, bloating, and diarrhea.

Some people also experience fever and chills when they consume spoiled products. If you have consumed spoiled oat milk and are experiencing any of these symptoms, you should consult a medical professional immediately.


Vomiting is another negative effect of consuming bad oat milk. It is the act of expelling stomach contents through your mouth.

It’s important to know when to get help from a medical professional because vomiting can have serious health consequences. If you’re vomiting blood or green fluid, you should seek immediate medical attention.

Vomiting usually occurs after eating too much or accidentally consuming something that causes irritation in your stomach, such as bad oat milk. This can be caused by food poisoning, an allergic reaction to medications, or even drinking too much alcohol.

Staying hydrated during this time and drinking lots of water can help flush out the toxins in your system if you’ve gotten food poisoning.

You should also avoid taking other medications while experiencing symptoms of food poisoning until you’ve consulted with a doctor first.


If you’re consuming oat milk that has gone bad, you may experience symptoms like diarrhea. Many things, such as bacteria, viruses, food poisoning, or an allergy, can trigger this condition.

Diarrhea can cause a variety of uncomfortable side effects, such as nausea, gas, and bloating in the stomach. These unpleasant symptoms can be mild or severe, depending on the cause of your diarrhea.

If you have diarrhea that lasts longer than 48 hours, contact your primary care provider immediately because they may need to prescribe antibiotics to treat the infection.

Abdominal Cramps

If you consume oat milk that has gone bad, you may experience abdominal cramps. The most common cause of abdominal cramps is food poisoning, which happens when bacteria or viruses contaminate food. 

The other possible causes of abdominal cramps include appendicitis, irritable bowel syndrome (IBS), stomach flu, and ulcers. You should consult a doctor if your abdominal cramps last for more than two days or if you have a fever with them.

Allergic Reaction

If you consume oat milk that has gone bad, you may experience an allergic reaction. Allergic reactions can potentially be serious and even life-threatening. They can occur when your immune system overreacts to a substance that normally wouldn’t cause a problem. 

When this allergic reaction happens, your body releases chemicals that lead to inflammation in your body tissues and organs.

This inflammation can cause symptoms like hives and itching, as well as swelling of the throat or tongue, trouble breathing or swallowing, dizziness and fainting.

Oat milk can trigger an allergic reaction in people who are sensitive to or allergic to gluten.

After ingesting spoiled oat milk, if you experience any allergic reaction symptoms, such as hives, you should immediately seek medical attention by calling 911 or going to the nearest emergency room.

Best Way To Store Oat Milk

Oat Milk

You can find oat milk in most supermarkets and cafes, and it’s a great alternative to cow’s milk. But if you’re looking for the best way to store oat milk, you’re going to need to keep it cold.

You can store oat milk in your fridge for up to one week after opening. You should probably freeze it if you want to keep it for any longer than that. That way, you can always satisfy your cravings by having some on hand.

If you buy oat milk in bulk or if you tend to use it up quickly, consider investing in an airtight container or a mason jar with an airtight lid. You can just keep those on hand, so they’re ready when you need them.

Follow these tips for storing your oat milk to make it last longer.

  1. Store in the fridge.
  2. Keep it away from other foods, as it can pick up odors and flavors from other foods in the fridge.
  3. Be sure to clean out the container thoroughly after each use, as bacteria can grow on the residue left behind from previous uses of that container if not cleaned regularly.

RELATED: Is Eating Raw Oats Healthy?

Can You Freeze Oat Milk?

You can freeze oat milk, and it will keep for up to 3 months in the freezer. Freezing your oat milk is an excellent way to preserve the freshness of your product, but it also makes it easy to have on hand whenever you need it.

This can be especially helpful if you use oat milk as a base for recipes or drinks that require a liquid base.

How To Freeze Oat Milk

To freeze your oat milk, simply pour it into ice cube trays and place them in the freezer until they have frozen through (about 6 hours).

Then transfer them from the trays into some sort of container that will protect them from freezer burn while they’re stored there.

You can use any type of plastic bag or container with a lid for this purpose, but some people find that using glass containers helps keep their product fresher longer.

Once your cubes are frozen , you can remove them from their trays and store them in a freezer-safe plastic bag or container until you’re ready to use them again. This will help prevent them from getting crushed together when you take them out of storage later on!

Preserving Oat Milk

Oat milk’s shelf life is about two weeks. Here are three ways to preserve your oat milk so you can enjoy it for longer:

Freeze It: To freeze your oat milk, simply pour some into ice cube trays and pop them in the freezer. Once the oat milk is frozen, put them into a freezer bag or container for storage.

You can use these cubes in smoothies or as an ingredient in baking recipes that call for milk or cream. Double-wrap any leftovers before placing them in the freezer, so they don’t thaw out when you open the package later on.

Make Butter: Oat butter, like peanut butter, has long shelf lives because they’re made with oil instead of water—but they still need to be refrigerated!

Try making your own oat butter by blending the oats together with some oil and storing them in a lidded jar, so you don’t have to worry about getting everything out each time you want something sweet with your morning coffee or tea.

Purée Your Milk Into A Drinkable Substance: Don’t throw away those leftover oats! Purée them into a smoothie-style drink anytime.

Different Types Of Oat Milk

Oat Milk

Plain Oat Milk

Plain oat milk is the most basic type of oat milk, and it’s also the least expensive. Plain oat milk is the most common and simplest variety. It is made from oats that have been soaked in water, which separates the starch from the protein.

The starch is then filtered out to be used as a thickener or added to other foods like soups or sauces. The remaining liquid is called oat milk.

You can use it as a milk substitute or add it to smoothies, cereals, and other foods. Plain oat milk will spoil after about two weeks in the refrigerator.

Whole Oat Milk

Whole oat milk is an upgrade from plain oat milk because it retains more of the nutrients found in whole oats than in its counterpart. It also has a higher percentage of oat extract than plain oat milk and therefore contains more fiber and protein.

Moreover, whole oat milk also contains other vitamins and minerals that help keep you healthy overall. 

It has a slightly sweeter flavor than plain oat milk because it has not been filtered as much during processing. Like plain oat milk, whole oat milk will spoil after about two weeks in the refrigerator.

Cream Oat Milk

Cream oat milk is created by adding cream back into the original liquid after it has been strained through cheesecloth or another similar device to remove any pulp or fiber that may still be present after separating out the starch.

Cream oat milk tends to have an even richer flavor than regular whole-oat milk because it contains more fat than either plain or whole varieties of this beverage product line.

Unsweetened Oat Milk

Unsweetened oat milk is made from ground oats, water, and sometimes other ingredients like brown sugar or vanilla. It’s usually sweetened with stevia or agave nectar. This type of oat milk has a nutty flavor that works well in smoothies and over cereal.

It doesn’t spoil easily, so you can keep it at room temperature for up to three days after opening.

Sweetened Oat Milk

Sweetened oat milk has a similar taste and texture to regular cow’s milk but without all the extra calories from saturated fat!

Sweetened varieties are usually made with cane sugar or honey instead of artificial sweeteners like aspartame or sucralose. Like unsweetened oat milk, they can be kept at room temperature for up to three days after opening.

Vanilla Oat Milk

Vanilla oat milk is a plant-based milk alternative that’s made from oats, water, and a touch of vanilla. It’s made with the same process as all other oat milk but with the addition of vanilla flavor.

This type of milk has a thinner consistency than other varieties, making it great for adding to coffee or tea. It also tends to spoil faster than other types of milk because of its higher-than-normal water content.

Chocolate Oat Milk

Chocolate oat milk is the latest in the oat milk revolution. It’s made by blending oat milk with cocoa powder and adding a little bit of sweetener.

It’s great for people who want a healthy drink that tastes like a chocolate milkshake. You can keep chocolate oat milk for about 2 weeks in your fridge, but it’s best to use it up before then because of its low shelf life.

Hazelnut Oat Milk

Hazelnut oat milk is made from ground-up oats and sweetened with hazelnuts.

It’s a good choice if you’re lactose-intolerant and want to enjoy the rich, nutty flavor of oatmeal in your morning cup of Joe. Hazelnut oat milk spoils quickly, which means that you should store it in the refrigerator. 

RELATED: Everything You Need to Know About Oats: The Wheat-Free Alternative

Frequently Asked Questions

Does Homemade Oat Milk Spoil Faster Than Store Bought Oat Milk?

Homemade and store-bought oat milk should last about the same amount of time. Both are made from fresh oats that have been soaked in water and strained, so they will spoil eventually but not because of anything inherent to oat milk.

Oat milk is made by soaking oats in water, then straining them through a fine mesh sieve or cheesecloth until you’re left with a thin liquid that resembles milk.

As long as you keep your oat milk refrigerated and don’t add any additional ingredients like honey or vanilla, it should last about as long as store-bought oat milk.

However, most store-bought milk contains some form of preservative, usually vitamin A palmitate or sodium metabisulfite, which extend the shelf life of their product by slowing down the growth of bacteria that could cause spoilage.

These preservatives may also affect how quickly your body absorbs nutrients from your food, so if you find yourself experiencing digestive issues after drinking store-bought oat milk, consider switching over to homemade.

Is Homemade Oat Milk Better Than Oat Milk From The Stores?

You might wonder if it is better for

you to make your own oat milk or buy it from the store instead. 

Making your own oat milk is fun and easy. The advantages of making your own oat milk are plentiful. For one thing, you can customize the flavor however you want, and if you don’t like the taste of oat milk, you can try another kind of milk.

But what about the cost? Is it cheaper to buy oat milk from the store than it is to make it yourself?

The answer depends on what kind of oats you use and where your store gets its products from.

If you buy organic oats from an online grocer and make your own oat milk at home with a Vitamix blender, then yes—it is much cheaper than buying it from a grocery store or other retailer.

However, if you want a quick solution that doesn’t call for any specialized tools or cooking expertise, then picking up a carton of oat milk from the store might be the way to go!

What Are The Health Benefits Of Oat Milk?

Oat milk contains more fiber than cow’s milk and is richer in antioxidants, which can help fight free radicals in the body.

The fiber in oat milk helps you feel fuller longer and can help lower cholesterol levels. It’s easy to drink without worrying about putting on weight because it has few fat and calories.

Oats are high in protein and contain essential amino acids, which help build muscle tissue.

This makes oat milk an excellent choice for those who exercise regularly because it provides energy without being high in calories or fat like some other types of milk products, such as regular dairy products or soybean oil-based alternatives like almond milk or coconut milk which also contain protein.

Oat milk is relatively easy to tell if it's gone off. Here's how:

Oat Milk Is Relatively Easy To Tell If It's Gone Off. Here's How:

Active Time: 5 minutes
Total Time: 5 minutes
Difficulty: Easy

You can tell if your oat milk has gone bad by the liquid's smell, taste, and color. If your oat milk tastes sour or smells bad, it's likely gone bad and should be discarded.

If you notice that the liquid looks darker than usual, it could be a sign that it has spoiled. If this happens, you should immediately throw away your oat milk and not consume more.


  • Oat Milk


  • No special tools needed


  1. Check the date on the carton. If you see a "use by" or "sell by" date on your carton of oat milk, that's an indicator that it was packaged recently and should be safe to consume until then.

    The freshest oat milk will usually have a sell-by date that is less than two weeks away. 

    It would be printed on the bottom of the container, directly underneath, where you would find a barcode if it were in a store.

    The date is usually written out as "mm/dd/yyyy," so if it reads "12/30/2018," that would mean it expired on December 30th, 2018.

    The sell-by date is the date that indicates when the product should be sold.

    This date is typically printed on the front label of the oat milk container and will be different from one brand to another.

    The use-by date is the date that indicates when a product should be consumed by its expiration date.

    The use-by date might be imprinted on a sticker on top of the oat milk container or on its side label.

    If you can't see a date, don't drink it. If there's no printed expiration date on your oat milk, it could mean that it's past its prime or just simply wasn't packaged with one in mind.

    Either way, you'll want to discard this product and find another carton before using it in your morning routine.
  2. Smell the oat milk. To check if oat milk has gone bad, you will want to smell it. Oat milk has a very distinct smell, and it's not just because it's coming straight out of the container.
    It should smell like oats, not spoiled food. When oat milk is fresh and unspoiled, there should be no other smells but maybe a hint of sweetness in the air.

    Odor changes are a telltale sign that your oat milk has gone bad. The first indication of this happening will be a sour or rancid odor coming from your container.
    This indicates that your oat milk has been exposed to bacteria and other substances that can spoil food.

    If you're able to smell a strong odor from the container, then it should be thrown away. In addition, if there is even a slight scent of something off and you can't place what it smells like, then we recommend throwing the product out anyway.

    If you can't smell anything from the container, then it's probably fine. 

    Remember that the smell test isn't foolproof and should only be used as an indicator of whether or not something is safe to consume or not.
  3. Look for separation in the oat milk. If you notice that the liquid looks separated from the oats, it means that bacteria have grown inside the oat milk and caused it to go bad.
    This can happen if the oat milk has been sitting around for a while and the fats and water have separated, which will make it look like there's a layer of oil on top of your drink.

    Oat milk also has a tendency to curdle when it's left out for too long, so that might be another sign that something is wrong with your bottle of oat milk.
    To test this out, simply pour a small amount of the liquid into a glass and see if there's a layer of clear liquid above or below the paste-like layer in the center. If this happens, throw out your oat milk immediately.
  4. Taste a small amount to see if it tastes off. The best way to check if your oat milk has gone bad is to taste it. Oat milk is supposed to have a sweet, creamy taste that's somewhere between almond and soy milk. 

    Bad oat milk will taste like rotten fruit or spoiled milk. If oat milk has gone bad, you will be able to tell right away because the taste will be unpleasant.

    If the milk tastes bad, don't drink it. You'll want to throw it out and start over with a fresh carton. On the other hand, if the milk tastes fine, you can use it for cooking or baking, depending on how much you have left.
  5. Check for mold in the oat milk. Mold spots are the most obvious sign that your oat milk has gone bad. It is a type of fungus that can grow on food, especially dairy products like oat milk. When it appears on your oat milk, it's time to throw it away.

    If you see any mold on top of the milk or floating in the container, throw it away immediately. You should also throw away containers if they are leaking, have cracks or nicks in their lids, or if the lid is hard to open or close.

    Mold grows best in warm temperatures and moist environments. When your oat milk goes bad, this means that it has been exposed to these conditions for long enough for harmful bacteria and fungi to start growing inside. 

    When it comes to mold on your oat milk, there are four types:

    Fusarium: Causes allergies and respiratory problems in humans and can be found on corn and wheat products
    Aspergillus: Causes nasal congestion, wheezing, and asthma symptoms; can also cause a severe allergic reaction
    Penicillium: Can cause respiratory problems and skin infections; primarily found on strawberries but also on other foods such as peanuts, almonds, and wheat
    Cladosporium: This type of mold can cause allergic reactions, including skin rashes and hay fever.
  6. Check the carton for bulging. If it seems to be puffing out, this is a sign that the milk has gone bad and should be thrown away.
    This happens because oat milk is made with water and oats, which expand when they come into contact with air.
    The oats absorb water during processing and then expand again when they're sealed inside a carton or other container.

    The pressure buildup in an oat milk container can cause it to burst open or leak out of its packaging.
    This happens most often when a product hasn't been refrigerated properly or has been left outside for too long.
    It can also happen when there's an unexpected change in temperature between where you store your oat milk and where you take it out.

    Also, acids in spoiled oat milk can cause a chemical reaction that makes the product bulge or leak.
    When this happens, it indicates that the natural oils in the product have broken down and changed from liquid to solid form due to bacteria.
  7. Look for cloudiness or a white film on the surface of the oat milk. Oat milk that has been left open to the air will develop a white film and may start to smell sour. 

    Cloudiness or a white film on the surface of oat milk is caused by fermentation. The fermentation process is the same as how yogurt is made, but it happens naturally in oat milk rather than taking place in a lab.

    This is also what happens when you leave fresh milk out for too long. If your oat milk has developed this characteristic, it's best to throw it away.
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