Why Does Creamer Curdle In Coffee And Is There Anything You Can Do About It?

Are you wondering, “Why does creamer curdle in coffee?” This article discusses the various reasons and ways to avoid dealing with chunks in your cup of Joe.

why does creamer curdle in coffee
All creamers can curdle in the right/wrong conditions

No one among the 182.45 million Americans who add coffee creamers to their daily cup of Joe appreciates the chunks of creamer floating in their coffee, myself included. I even thought it might be my creamer type or coffee cup, so I jumped from brand to brand, to no avail.

So, what causes coffee creamers to get chunky? If your coffee creamer is not expired, then it’s the acidity, temperature, water, and how creamer is added to the drink. Virtually all creamers can curdle in the right (or should we say ‘wrong’!) conditions. Read on to find out how to ensure your creamer blends just right with your coffee.

Why Is My Coffee Creamer Curdling?

If you’ve ever experienced a carton of milk way past its sell-by date, you know it can turn into lumpy mush over time. While that’s one way to curdle dairy, you can achieve the same effect by adding acidic liquid (like coffee or lemon juice).

All dairy products contain proteins, including casein. When creamer is liquid, these proteins are stable and don’t clump together. When you add acid to the mix, the proteins break down and start attaching to each other, creating curds (aka curdling). 

This process is necessary for various dairy products like cheese and yogurt, but it can be off-putting when it happens in your cup of coffee or when you see cream curdle atop your dessert. Below, we look further into the curdling process and why your creamer sometimes looks lumpy when it hits your coffee.

It’s Expired

Using an expired product is one of the most common reasons coffee creamers become chunky. For the best coffee, you need to ensure that you are using a fresh creamer.

Aside from the expiration date, the creamer may already be spoiled. Non-dairy coffee creamers don’t always show changes in texture, taste, or smell. In contrast, dairy-based creamers can be spoiled even long before expiration due to the lactic acid that builds up over time after opening.

Here are a few tips you can follow to avoid adding spoiled creamer to your coffee:

  • Always check the expiration date before using the creamer. However, this should not be used as gospel. Trust your instincts if the creamer seems rancid but is still within its printed shelf life.
  • Store it properly. This applies to dairy creamers and their non-dairy alternatives, such as plant-based milk.
  • Inspect its smell and taste. If it smells terrible and tastes sour, it’s time to throw it away.
  • If it doesn’t have changes in taste and odor, try adding it to some to coffee in a separate cup first.

Acidity Level

High acidity in your coffee can cause creamers to be not only chunky but also taste sour. The acids cause the aggregation and solidification of casein, making them float in your coffee. This is caused by the rapidly changing ph balance within the cup.

Coffee becomes acidic during brewing. It’s the stage where coffee beans release nine primary acids. The size of the coffee grounds, brewing time, and roasting temperature contribute to the coffee’s acidity. 

Here’s what you can do to reduce the acidity of the coffee.

  • Add a pinch of salt or baking soda to neutralize the coffee’s acidity and prevent the coffee creamer from chunking.
  • Use a coarse dark roast for your coffee beans. They’re less acidic than lighter roast and are less likely to cause curdled cream.
  • Add eggshells to your ground coffee before brewing. It alkalizes and smooths your espresso.
  • Increase brewing time with low temperatures. This will affect the acidity level and ensure you get a good cup of coffee.

Water Quality

Water quality check using a chemical testing kit
Water can be acidic and contains impurities that aren’t removed during the filtration process

If the water looks, smells, and tastes okay, you may think it’s acceptable and safe to drink. While this is true, the water can be acidic and contains impurities that aren’t removed during the filtration process, causing your coffee creamer to be chunky. To avoid this, use pH Testing Strips to check the water’s quality.

You can also use a filter to ensure no impurities in your water. You might also find our explainer on why does my coffee taste like water helpful.


When the water is too hot, it can burn your coffee. It’s the same with the coffee creamer. It’s sensitive, and the milk proteins tend to clump together due to sudden temperature changes.

Adding chilled liquid coffee creamer to hot coffee or powdered creamer to ice-cold water results in clumps forming. Follow these coffee tips for less curdle in your cup:

  • Use a thermometer. Your coffee’s temperature should only be between 180 °F to 190 °F.
  • Wait for at least 60 to 90 seconds before adding your coffee creamer (we know it’s difficult to wait for that first cup of coffee in the morning!).
  • Warm the chilled liquid coffee creamer before adding it to your cup of Joe. If you add it at below room temperature, it is much more likely to curdle.
  • For iced coffee, put coffee and ice at the same time into the glass and pour creamer a few minutes later. Dissolve it in a separate cup with hot water if you’re using powdered creamer. This is what you see expert coffee drinkers do, and they’re doing it for a reason.
  • If you don’t like putting creamer first into your drink, you can use a teaspoon, chopstick, a stir stick, or a tiny whisk to mix your creamer.


Putting sugar and creamer in a cup before coffee can cause creamers to be chunky. This is because the sugar will absorb all the water molecules in the coffee creamer, causing casein to solidify when the coffee is added.

It’s suggested that coffee makers dissolve their sugar in hot coffee first before adding the coffee creamer or using sugar syrup to minimize curdling.

The Coffee Creamer Used

If you’ve done all the tips above and it is still the same, the problem could be your coffee creamer. Using a non-dairy creamer with nut milk as its base can create chunks in your coffee.

Improper storage of powdered creamer can also be the root of the problem. Storing it in the refrigerator can create moisture that causes clumping, making it difficult to dissolve in your drink quickly. The best way to solve this issue is by knowing your creamer and its ingredients.

Tasty nut milk on the table
Nut milk as its base can create chunks in your coffee

Additionally, make it a habit to store your coffee creamer in the right place according to the packaging. Try using alternative coffee creamers with fat cells around proteins, like half-and-half and heavy creams that don’t curdle quickly. Other creamer alternatives you can use are whole milk, non-dairy milk, and evaporated milk.

Milk alternatives like almond milk, coconut milk, oat milk, and soy milk can all curdle since they contain proteins. However, rather than breaking down casein (which is only in animal milk), the coffee acts as a coagulant. Typically, soy milk curdles the easiest.

Can You Really Avoid The Curdle?

Overall, if you want to avoid curdled creamer in your coffee, you might have to experiment with a few prevention tactics. That being said, because coffee is such a distinct beverage and so many people have unique preferences, you might have to take a few lumps every so often (pun intended). Or, you can visit coffee shops and let the barista make your drink perfectly and curd-free every time.

Is It Okay To Drink Curdled Cream In Coffee?

It’s hard to tell when your non-dairy coffee creamers have gone bad because they don’t show changes in texture or taste. But for liquid creamers, once it develops chunks, taste, and smell sour that it’s time to chuck them in the bin.

Always check the packaging for the best-before date, smell, taste, and consistency before adding it to your coffee. If it’s bad and not the same as when you first opened it, throw it away. If milk curdles from old age, it’s toxic and can make you sick.

However, if curdling occurs from a chemical reaction, it’s safe to drink, albeit far less tasty. 


  • Cian Murray

    Cian Murray is an experienced writer and editor, who graduated from Cardiff University’s esteemed School of Journalism, Media and Culture. His work has been featured in both local and national media, and he has also produced content for multinational brands and agencies. Find Cian on muckrack.com.