Does Oat Milk Curdle or Not? Oat Milk Facts to Know

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You may wonder, especially if you love this non-dairy milk, does oat milk curdle? Yes, it does! Though oat milk isn’t traditional “milk”, it can, and often does, curdle. So, why does this occur and what can be done to stop it? Those are great questions. Join us as we delve into the chemistry of curdled oat milk.

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Table of Contents

Does Oat Milk Curdle

Why Does Oat Milk Curdle?

Oat milk curdles when it either becomes too hot or too acidic.

Oat milk is composed of oats that have been blended into water, strained, and emulsified for better consistency. This non-dairy milk can break down and become curdled, however, when exposed to acid or after becoming too hot. Sometimes this separation can be fixed with further emulsifying (shaking, blending, or using an actual emulsifier).

Is Curdled Oat Milk Bad?

Curdled oat milk can be bad, but in most cases, it is not.

For example, there are some instances in which your oat milk is curdling or separating because it is about to expire. If you’ve allowed your oat milk coffee creamer to sit out too long, or if your oat milk has gone past expiration, it could be that you need to opt for fresher oat milk.

On the other hand, there are many instances in which curdled oat milk isn’t bad at all. If you’re going for visuals, then yes, your coffee or whatever you are putting your oat milk in may look unappetizing, but the flavor will be the same.

In terms of whether or not oat milk that is curdled will harm you, the answer is easy. Curdled oat milk will not harm you unless the reason for the curdled oat milk has to do with its lack of freshness.

Can You Drink Curdled Oat Milk?

Assuming that your oat milk is fresh, drinking curdled oat milk is completely safe.

Regardless of this fact, for many, the look of curdled milk is enough to cause them to lose their appetite. That’s because curdled milk is generally associated with spoilage. In this instance, however, curdled oat milk can occur for many reasons. Most of those reasons have nothing to do with spoilage, but rather the pH or temperature of the drink.

The top of a foamy drink.

Should Oat Milk Have Bits in It?

Oat milk can definitely have bits in it.

If you’ve ever noticed what appears to be small white flecks in your oat milk, don’t be alarmed. Sometimes, these flecks aren’t completely blended out and float in suspension in oat milk from time to time. Occasionally, you may be able to shake the carton to help the flecks dissipate.

If shaking doesn’t work, the oat milk should still taste fine and should keep its general consistency. If it doesn’t, the oat milk may not have been fresh, to begin with.

Should Oat Milk Have Chunks?

Oat milk may have chunks in it. These will be similar to the unblended white flecks mentioned above but may be larger. When you observe these, you shouldn’t be worried.

Remember that the way in which oat milk is made is by blending oats with water until creamy before straining. Sometimes, little bits, flecks, or “chunks” may get missed. This is a normal occurrence and does not signify that anything is wrong with your oat milk.

Pacific Foods Organic Oat Original Plant-Based Milk, Organic Oat - Original, 32 Fl Oz (Pack of 12)

Oat Milk Separating in Coffee

Some people notice that their oat milk separates in coffee. Some don’t notice this at all.

The difference likely lies in the brand of oat milk used. Many brands consist of different ingredients and emulsifying techniques. Some brands of oat milk are even formulated to withstand higher heat temperatures and stand up to acidity. These make them more suitable for use in coffee houses. The Oatly, Arpo, and other “barista” targeted brands are great examples of oat milks like these.

Oatly - Oat Drink - Barista Edition - 1L (Case of 6)
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Oat Milk Curdling Questions

Does Oat Milk Curdle in Your Stomach?

It is possible for oat milk to curdle in your stomach.

The stomach is a highly acidic place, and as such, oat milk may curdle in the stomach before it is finally digested.

Having said that, your body will most likely handle oat milk better than cow’s milk, especially if you are experiencing an upset stomach, to begin with. Milk in the stomach can produce gastric issues for some, though others may remain unaffected.

woman holding stomach

Does Oat Milk Curdle When Heated?

Oat milk may curdle or separate upon reaching certain temperatures. However, this is not the case with all oat milks.

As mentioned before, some oat milks are formulated to withstand higher temperatures and retain their creaminess when coming in contact with acidic coffee. Other brands may not be this way, so you may wish to anticipate a little curdling from oat milk if you plan to heat it–even though it doesn’t always happen.

Does Oat Milk Curdle When Boiled?

Oat milk may curdle or separate when boiled, but again, it will depend on what kind of oat milk you are using.

Oat milk that is formulated for baristas may not curdle or separate, but normal oat milk may be able to withstand heat as well. Just know that boiling oat milk will sometimes change the consistency; some have found that their oat milk becomes slimy after reaching certain temperatures.

Note: If making oat milk at home, there are procedures you can follow to prevent it from becoming too slimy. Check out this video to learn how to achieve perfect oat milk results every time you make it.

Does Oat Milk Curdle In…

Does Oat Milk Curdle in Coffee?

Oat milk may not always curdle in coffee, but it certainly can. Whether you are making a cappuccino or iced coffee, if you notice that your oat milk is curdling, it’s likely a chemical reaction happening between your oat milk and coffee. The higher levels of acidity and possibly the heat of the coffee may be causing the oat milk to curdle. This is especially true if your coffee is hot and your oat milk is cold.

To prevent this from happening, consider warming your oat milk and adding hot coffee, slowly, to your already poured oat milk. This will work to temper the oat milk so it doesn’t react so negatively to the difference in temperature.

If your oat milk continues to curdle beyond this, you may wish to try a darker coffee roast, as medium and lighter roasts may contain more acid. Cold brews are also lower in acid.

Does Oat Milk Curdle in Coffee If It’s Expired?

Oat milk that is expired, or closer to its expiration date, may be more likely to separate or curdle when exposed to coffee. Thus, it is better to use fresh oat milk, especially if you are worried about the aesthetics of your coffee.

Of course, to know whether or not your oat milk is fresh, you should check the date printed on the label and note changes in color, smell, and consistency.

If your oat milk is homemade, it will typically expire within about five days.

While many people use oat milk as a non-dairy replacement for milk in coffee, there are many other uses for oat milk than this. Check out the following frequently asked questions concerning oat milk curdling to get the details on how oat milk stands up against certain liquids and beverages.

Does Oat Milk Curdle in Tea?

Oat milk may curdle in tea. However, it is important to know that most teas aren’t as acidic as coffee, but every tea is different in terms of pH. Therefore, though oat milk curdling may not be as likely in tea as it is in acidic coffee, keep in mind that it can still happen.

Not only this, but the temperature of your tea can also play a big role in whether or not your oat milk separates. Be sure to warm your milk first before adding it to your tea to lessen the chances of curdling and separation from occurring.

Does Oat Milk Curdle With Lemon?

Because lemon has a pH of around 2–hence the sour taste–you can bet there is a chance that your oat milk could curdle when combined with lemon. When introduced to other acidic fruits such as strawberries, you may notice curdling or separation as well.

Keep in mind that whether or not your oat milk separates and curdles may not be a big deal if you are using it to cook or bake. Many people like to add lemon juice to plant-based drinks to produce dairy-free buttermilk. Others like to infuse strawberries in their oat milk to use to make lactosefree strawberry oatmeal. Either way, the curdling and separation won’t matter much once the liquid is cooked and dispersed throughout the dish.

milk with lemon

Does Oat Milk Curdle With Alcohol?

Yes, oat milk may curdle with alcohol.

Alcohol is neither considered acidic nor basic according to the Arrhenius Definition of bases and acids. Still, you can expect oat milk to curdle like regular milk curdles when combined with alcohol. However, as previously mentioned, this may not have a very profound effect on something that you are cooking.

If you are combining alcohol with oat milk for the purposes of drinking, you may need to emulsify the drink or simply be okay with the curdled look of the drink!

Does Oat Milk Curdle With Vinegar?

Oat milk may certainly curdle upon contact with vinegar, but not always. It’ll depend on how much vinegar you use, how long it sits, the brand of oat milk you use, and the freshness of the oat milk itself.

How Do You Keep Oat Milk From Curdling?

Now that you know the reasons that oat milk tends to curdle, it’s time to tackle how to keep this from happening in the first place.

Consider the following tips for keeping your oat milk from curdling:

  1. Know Your Brand: Buying the right kind of oat milk from the start can really help nip curdling oat milk in the bud. Try reaching for “barista” brands of oat milk rather than traditional types. These have been specially formulated to withstand certain conditions and may work better for your needs.
  2. Warm the Milk Beforehand: Sometimes cold oat milk curdles because of the sudden change of temperature when combined with something hot. Consider gently warming your oat milk before adding it to a hot beverage or liquid. Avoid boiling oat milk as this may cause it to change consistency.
  3. Add the Coffee to the Milk: If using oat milk for coffee, consider warming the oat milk gently and then adding the coffee to the oat milk rather than the other way around. This can temper the oat milk and prevent curdling better than adding cold oat milk directly to a hot mug of coffee.
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Does Oat Milk Curdle? Yes, It Does!

So, does oat milk curdle? It absolutely does!

Oat milk curdles much like regular milk, but it isn’t likely to hurt you. Some oat milks curdle because they aren’t fresh, but by and large, many oat milks curdle as a result of being introduced to something acidic.

When this happens, you can shake, stir, or blend the concoction to emulsify everything back together. Otherwise, curdled oat milk, though ugly, isn’t likely to hurt you in the end.


Why does oat milk curdle in coffee?

Oat milk curdles in coffee, usually in reaction to the acidity of the coffee. Consider purchasing darker roasted coffee or adding oat milk to cold brew instead. These coffee types are usually lower in acid. Otherwise, you may consider warming your oat milk before adding it to your coffee to see if that helps.

Is curdled oat milk bad?

Curdled oat milk can be bad, but in most cases, it is not. 

Can I drink curdled out milk?

Assuming that your oat milk is fresh, drinking curdled oat milk is completely safe. 

By Anna

Anna Brooks, the voice behind, is a seasoned writer and editor with an insatiable love for food. While not a professional chef, her culinary adventures and unique insights have captivated readers for years. Anna believes in the transformative power of food, stating it "feeds the soul." Dive into her writings for a mix of inspiration, entertainment, and culinary wisdom. Author Pinterest Facebook Twitter Instagram YouTube Tumblr Reddit Quora

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