Why Is My Protein Shake Foamy? 4 Reasons & Is It Bad?

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If you’ve ever been weirded out by small, foamy bubbles on the top of your protein shake and worried if the protein powder or another ingredient had gone bad, you’re not alone!  

I used to worry that I shouldn’t drink the foam, or that it meant I needed to blend my protein shake again.

So, why do protein shakes get foamy?  The foam in a protein shake has to do with the chemical structure of protein for both the whey powder and, if applicable, the liquid it is mixed with. Foamy protein can also occur because of how it’s mixed; more foam from vigorous shaking and less foam from stirring. The foam isn’t bad, but it can cause bloating. 

Just because you can drink the foam from protein shakes, you may decide you don’t want to.  As such, I’ll explain how to get rid of foam in your protein shakes, and other details such as:

• What the foam in protein shakes actually is
• Whether it’s bad to have a foamy protein shake
• Whether you can drink the foam in your protein shakes

What Is The Foam In Your Protein Shake?

The foam in a protein shake is small trapped air bubbles, the same as the foam that is formed when a barista steams milk for an espresso drink like a latte or cappuccino. 

It is NOT internally-generated gasses from spoiled food, unless your protein shake has been sitting for a week or more (if that’s the case, throw it out and don’t drink it).

Is It Bad That Your Protein Shake Is Foamy?

No, it’s not bad that your protein shake is foamy.  

The ability to form foam is actually a desirable attribute of protein.  It’s what allows egg whites to be whipped into meringues, as an example.  

The higher the quality and content of protein, the more foam is likely to be formed, regardless if the protein is in a powder or part of a whole food.

Can You Drink The Foam In Your Protein Shakes?

Yes, you can drink the foam in your protein shake.

In fact, I recommend drinking the foam because the protein “skin” that traps the air bubbles is part of the overall protein content of your shake.  

Another reason that some people like to drink the foam is that they find it makes the shake even more filling because it takes up more space in their stomach.  Feeling full for longer can be very helpful if your goal is to lose weight because it will reduce hunger.

Or, if you’re like me, you just like the thick texture of a foamy protein shake.

But, if the bubbles cause gassiness or bloating for you, then it’s best to get rid of the foam or make foam-free shakes.

Before you put in the time and effort to get rid of the beneficial foam, you will want to be sure that it’s truly the bubbles that are causing your problems.

Keep in mind that digestive distress from protein shakes can also be caused by:

• Lactose intolerance
• Sugar alcohols
• High fiber content
• Fillers or other additives
• Drinking the shake too quickly
• Having a milk protein allergy

After you’ve ruled out the factors above and you’re sure it’s the bubbles causing your discomfort, then you can check out my tips later in this article for getting rid of the foam.

4 Reasons Whey Protein Shakes Get Foamy

Properties of Protein

Protein is not only a macronutrient, but also a macromolecule, meaning that it is made up of smaller components.  

In the case of protein, these smaller components are the individual amino acids (the building blocks of protein).  

Shaking or blending protein powder causes the amino acids to stretch out.  

Some of these amino acids repel water (hydrophobic) – these stick out into the air.  

Others are attracted to water (hydrophilic).  This creates a thin web that traps air in between the water molecules at the surface of the protein shake.  The trapped air is a bubble, and lots of tiny bubbles make a foam.

• Related Article: How Long Do Protein Shakes Last? (I Tested It)

Blending With Milk And/Or Eggs

Since milk is naturally high in protein (milk protein is a combination of whey and casein proteins), it has foam-producing properties on its own.  

Similarly, some people like to blend whole eggs or egg whites into their protein shakes, but egg white protein also readily foams.

• Related Article: Can You Mix Whey With Eggs?

Vigorous Shaking or Blending

Shaking really vigorously or using a high-speed blender will naturally whip more air into a protein shake and make it foamier.

Thickening Agents

Other common ingredients in protein powder can also contribute to foaminess.  

Xanthan gum, a common thickening agent, leads to foamier protein shakes than protein powders without xanthan gum.  

Thickeners slow the rate at which foams dissipate.  Not all protein powders contain thickening agents, but many do, so check the ingredients carefully.

• Related Article: How To Mix Protein Powder Without A Shaker or Blender (7 Ways)

How To Get Rid Of Foam In Protein Shakes

The good news is that there are ways to get rid of the foam in protein shakes:

Stir It In

My top recommendation is actually to gently stir the foam back into your protein shake.  

Using a spoon will help to break the bubbles and release the trapped air, while ensuring that you still get all the protein and amino acids.

To be clear, what I’m suggesting is that you use a shaker first to mix the protein powder, THEN implement the stirring method

If you don’t shake first, the risk is that you might avoid the foam, but you’ll be left with clumps.  Some protein powders may dissolve by just using a stirring method, but most won’t.  

For example, I know that Optimum Nutrition Gold Standard Whey Protein can be stirred without forming clumps because I’ve tried it, but this isn’t the norm.

Scoop It Off

If you’re okay with missing out on a little bit of your protein shake or the bubbles just really bother your stomach, simply use a spoon to scoop the foamy part off the top of your protein shake and into a sink or garbage or compost bin.

Strain It Out

If you have access to a fine sieve, you can slowly pour your protein shake through it to get only the smooth, foam-free liquid in your cup, trapping any bubbles in the mesh.

How To Make A Protein Shake Without Foam

Here are some additional tips on how to make a protein shake with little to no foam in the first place:

Use Water Instead of Milk

When you make your protein shake with water instead of milk, you no longer have a liquid that will contribute to bubbles.  

Think about the bubbles that form when you blow through a straw into a glass of milk compared to a glass of water.   

Avoid The Blender

The high-speed action of a blender whips up lots of air bubbles.  This is great for people who like a thick, foamy protein shake (like me) but it’s a problem for anyone who deals with digestive discomfort such as gassiness or bloating from the air bubbles.

If you need the blender to liquefy other ingredients in your shake (such as fruit or vegetables), do that first, then add protein powder at the very end and blend in at the lowest speed, or shut the blender off completely and simply stir the protein powder in at the end to minimize bubbles.

Make Your Shake Ahead Of Time

If you prepare your shake before your workout, or even the night before, you will give more time for the foam to settle and you can gently stir just before drinking.  

This is similar to how the foam on a latte will “shrink” if the drink is left sitting.

Place your protein shake in the fridge and then, once you’re ready to drink, stir it for 10-20 seconds with a spoon and then enjoy. 

Mix A Little Protein Powder At A Time

Instead of mixing 1-2 scoops of protein powder into a shake all at once, add just a few spoonfuls at a time, stirring gently until fully dissolved before adding more.

Use Warm Liquid

Warm liquid that is at or above room temperature is better for dissolving protein powder than cold liquid.  Again, stir gently to avoid creating air bubbles.

Protein Powder That Doesn’t Foam

Since foam formation is a natural attribute of protein, there is no one protein powder that is going to be 100% foam-free.  As we saw, the method of preparing the protein shake is more important when it comes to the foaminess of the shake than the protein powder itself.

That said, there are some protein powders that will be less likely to create foam than others.  Since higher protein content means higher foam, I’d focus on whey protein concentrate which has a lower protein content compared to whey protein isolate if it’s really more important to you to get as little foam as possible versus getting the highest quality and highest protein content from your protein powder.

It’s also important to look for protein powders that do not contain added ingredients that contribute to foaminess, like thickening agents.  

I recommend Nutricost Whey Protein Concentrate as an option that meets these criteria.

Note: Keep in mind that unless you really need low foam (for example because of bloating or other digestive issues), a higher quality protein powder with a higher content of protein is likely to create a foamier protein shake. To get the best results from your protein powder, I do recommend using the highest quality protein powder possible, that still works for you.

Frequently Asked Questions

Does Using A Blender Always Cause Foam In Protein Shakes?

No, using a blender won’t necessarily cause foam in protein shakes if it is used at low speed.  Dissolving the protein powder by stirring it into a warm liquid first and then slowly adding it to the blender can also reduce the risk of foam.

Is Foam Common In Whey Protein?

Yes, foam is common with whey protein, especially for pure whey protein isolate with no fillers.  If the whey protein powder contains thickening agents, foam is even more common.