Does Oat Milk Curdle in Coffee? And How to Stop It


Does oat milk curdle in coffee? Yes, when exposed to an acidic environment, oat milk will curdle. Since oat milk is acidic paired with the acidity of coffee, the reaction and the milk curdling takes place quickly due to the high temperature of the coffee.

However, with that being said, it’s important to point out that the curdling of oat milk is less likely to occur compared to other plant-based milk options. 

pouring oat milk as creamer
pouring oat milk as creamer

Using oat milk in coffee has become a popular non-dairy creamer and one of the most popular non-dairy alternatives used by coffee shops and those who don’t tolerate lactic acid.

What is Oat Milk?

Oat milk is a liquid mixture that’s made by soaking oats in water, bending them, and straining the liquid with cheesecloth.  It’s a plant-based milk and has become a popular alternative to cow’s milk.

Oat milk has become a popular alternative to milk for coffee houses. 

What Does It Mean When Milk Curdles?

Curdling takes place when oat milk becomes lumpy. It’s a change in texture that can make it look like it’s spoiled, which can be the result of various circumstances, which is not uncommon when plant milk is used in coffee. 

Reasons For Oat Milk Curdling

Let’s take a look at all the potential reasons that your oat milk could potentially curdle, which will allow them to ideally be avoided.

Expired Oat Milk

If your oat milk has been opened for a while, has sat around in the refrigerator for several days, or has expired, this could potentially be the cause of it curdling.

oat milk in glass
oat milk in glass

High Acidic Coffee Bean

Using a highly acidic coffee bean can cause the oat milk in your coffee to curdle.  The acid from the coffee combined with the acid from the oat milk itself creates a fair amount of acid which can result in curdling. 

Unclean Coffee Cup

Check your coffee cup or mug before adding any liquid to it to make sure it’s clean. A coffee cup that has residue left inside it can potentially be the culprit behind the curdling.

High Temperature Coffee

If the temperature of your hot coffee is too high when the oat milk is added, this can be another reason the milk might curdle.

Storage Temperature

Storing oat milk too warm can cause it to curdle. For example, room temperature oat milk will be at greater risk of curdling, so be sure that it’s kept at the appropriate temperature to keep this from happening.

How to Keep Oat Milk From Curdling

Now that we’ve established the reasons oat milk curdles, let’s consider ways we can keep that from happening so that using it as a coffee creamer becomes an unhindered experience.

coffee added to oat milk
coffee added to oat milk

Use Fresh Oat Milk

One of the reasons oat milk curdles is because it’s expired or old.  To prevent this from happening, be sure to use a fresh batch of oat milk when adding it to your coffee.

Use Low Acidic Coffee Beans

Coffee beans with high acidity combined with oat milk that’s also acidic can be cause for the change in texture. To avoid this, use coffee that has a lower acid content.

Use Clean Dishes

Since dirty coffee mugs and utensils can be a culprit for oat milk to curdle, make sure everything is clean before the coffee and creamer is assembled.

Avoid Overheating

Avoid overheating your coffee and then adding the creamer. Since the high temperature of the coffee can be a cause for curdling, be careful not to make the coffee overly hot.

Coffee drinkers who’ve mastered using alternative milks recommend adding the oat milk to the coffee mug first and then adding coffee at a lower temperature.

coffee poured into oat milk
coffee poured into oat milk

Keep Oat Milk Refrigerated

Keeping oat milk refrigerated is our last tip for helping to avoid curdling. When it’s stored in too warm of a location and added to coffee, it can potentially cause it to curdle.

Is It Okay to Drink Curdled Oat Milk?

Let’s face it. Curdled oat milk floating in your coffee isn’t attractive nor is it appetizing. But is it okay to drink?

As long as no other signs of spoilage are present, it’s not going to hurt you to consume it. After all, yogurt and cheese are two examples of curdled foods that are widely consumed.

Is Oat Milk Good to Use in Coffee?

Yes, even though oat milk curdles in coffee, it’s one of the best plant-based milk alternatives for coffee because it curdles less than other plant-based creamers.

For the best results, pay particular attention to the factors that cause the curdling and try to avoid them.

Other Plant-Based Milk Options

For your reference, we’ve created this list of some of the best milk alternatives that are dairy free and are usefully for a variety of purposes including in coffee.

Many of these options qualify as vegan milk, depending on the brand and the ingredients used to make them.

Soy Milk

Soy milk is a non-dairy option that might work well for you. The only drawback is that it is sweeter than regular milk. And so your coffee will taste sweeter as a result.

coffee art with oat milk
coffee art with oat milk

Coconut Milk

Coconut milk can be a favorite ingredient to have on hand when making coconut cream pie and other coconut flavored desserts.

And some folks even use it regularly in place of regular dairy milk. Coconut milk indeed comes from coconuts and therefore has a coconut flavor.

Rice Milk

Rice milk is a dairy-free plant-based milk made from rice. It can be sweetened and flavored, which is not ideal for use in all types of coffee.

But if you’d like to use rice milk as a substitute, we recommend using unsweetened rice milk for better results.

Oat Milk

Homemade oat milk or store-bought oat milk is a non-dairy plant-based milk.

It’s made from soaking whole grain oats in water and extracting the plant material. It creates a milky substance that can be purchased in various flavors.

Almond Milk

As you might expect, cold almond milk tastes like almond. It is more so than just plain old milk. 

If you’re choosing to use almond milk, you’ll want to use about half as much so that you don’t alter the flavor too much.

Cashew Milk

Cashew milk is a non-dairy milk beverage that’s made from whole cashews and water.

It’s available in sweetened and unsweetened varieties and is full of vitamins, minerals, and healthy fats. It’s a good alternative for cow’s milk.

Pea Milk

Pea milk is a dairy-free milk, so it’s not cow milk by any means, but rather it’s made from the protein from milled yellow field peas.

One of the biggest benefits of pea milk is that it’s higher in protein than some of the other plant-based milks. 

Hemp Milk

Hemp seed milk or hemp milk is a plant based non-dairy option that’s created by grinding and soaking hemp seeds. The process results in a milky liquid in color and flavor.

oat milk in coffee
oat milk in coffee

Frequently Asked Questions

Following are frequently asked questions that relate to does oat milk curdle in coffee. If you have a question that’s not answered here, feel free to drop it to us in the comments box below and we’ll be happy to respond.

How do you keep oat milk from curdling in coffee?

There are several tips we’ve included above for how to keep oat milk for curdling in coffee.

The two most important factors are to use oat milk that’s fresh and that hasn’t been opened in the refrigerator for a long time and to use coffee that’s not too hot. 

Is oat milk supposed to separate in coffee?

When using oat milk in coffee, no one wants it to separate and that’s not the goal. See our list above for how to avoid letting your oat milk curdle after it’s added to your coffee.

What is the best milk alternative for coffee that doesn’t curdle?

Oat milk is the best milk alternative to use in coffee as far as curdling is concerned.  It has a nice creamy texture.

It’s just that learning how to use it needs to be mastered so unintentional curdling doesn’t take place.

Can you put oat milk in coffee?

Yes, you can put oat milk in coffee. Not only that, you can also use it to make latte art. It works well as a milk alternative and dairy free coffee creamer. You’ll just want to be careful as to how it’s used in order to prevent curdling.

Related Ideas:

Caramel Iced Coffee Recipe
Caramel Syrup for Coffee
Chick-fil-A Vanilla Iced Coffee Recipe
How to Make Iced Coffee Fast
Why Does My Coffee Taste Watery

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Sarah is known for her extra fancy yeast breads, melt in your mouth pies, and everything salads. She has won awards as a home cook, and is passionate about helping others feel smarter in the kitchen. Sarah is the cooking genius of the sister duo.

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