Why do protein shakes say do not freeze?

Protein shakes have become an incredibly popular dietary supplement among athletes, bodybuilders, and anyone looking to increase their protein intake. Most protein powders come with instructions to store in a cool, dry place and a warning: “Do Not Freeze.” But why can’t protein shakes be frozen? Let’s take a closer look.

The Effects of Freezing on Protein Powder

Freezing protein powder can damage its texture, taste, and nutritional quality in several ways:

Texture Changes

Freezing causes water inside the powder to expand and form ice crystals. These crystals can rupture the microstructures that give the powder its smooth, fine texture. When thawed, the damaged powder will be clumpy or gritty.

Flavor Changes

Ice crystals can also puncture the microscopic particles that contain the flavors. This causes the volatile aromatic compounds responsible for taste to escape or degrade. The resulting thawed powder will taste bland.

Nutritional Changes

The protein in powder is made up of delicate chains of amino acids. Freezing unravels their structures through a process called denaturation. Denatured proteins are difficult for the body to digest and absorb optimally.

Separation and Sedimentation

When frozen, the components of protein powder can separate from each other. This is because ingredients have different freezing points based on composition. Upon thawing, gravity pulls the separated substances into distinct layers. Shaking cannot fully recombine them.

Types of Proteins Impacted

Not all proteins are equally affected by freezing. Let’s look at how different protein sources handle being frozen:

Protein Type Freezing Tolerance
Whey Protein Low
Casein Protein Moderate
Soy Protein High
Pea Protein Moderate
Hemp Protein Low

As shown, whey and hemp proteins are the most unstable when frozen. Casein, soy, and pea proteins have a bit more resistance against freezing damage. But all proteins will degrade to some degree.

Other Ingredients Are Also Affected

It’s not just protein that is impacted by freezing. Other components of protein powders can suffer as well:


Emulsifiers are added to help evenly disperse the protein powder in liquid. Freezing can cause emulsifiers to break down, resulting in clumping when mixing the thawed powder into shakes.


Thickeners give protein shakes their desired smooth, creamy texture. They can separate and coagulate during freezing, making shakes thin and watery after being thawed.

Artificial Sweeteners

Sweeteners like sucralose and acesulfame K can crystallize during freezing. This imparts an unpleasant grainy texture and metallic aftertaste.

Natural Flavors

Added flavors from fruits, spices, etc can fade or degrade under frozen storage. This leads to a bland, unappetizing taste profile.

Vitamins & Minerals

Vitamins and mineral compounds are sensitive to freezing damage. Nutrient levels can diminish, reducing the supplement’s health benefits.

Does Freezing Denature All Proteins?

Freezing doesn’t completely ruin every protein’s structure and function. For example:

  • Frozen meats like chicken and beef regain much of their texture after thawing and cooking. However, excessive freezing can turn meats mushy.
  • Many people freeze milk and yogurt products with minimal issues. But separation and off-flavors may develop.
  • Eggs can be frozen, though the whipped consistency of thawed egg whites changes. Their ability to create foams can be reduced.

So while freezing does denature proteins to some extent, foods have protective structures that limit damage. Protein powders lack these protections, making their proteins far more vulnerable.

Avoiding Freezer Burn

Another risk of freezing protein powders is freezer burn. This occurs when moisture evaporates from the powder’s surface, causing dry, shriveled spots. It especially develops if powders are frozen in bags with too much air space.

Freezer burn makes powders taste stale and unpalatable. It also further degrades nutritional quality. So if you do freeze powders, take steps to avoid freezer burn:

  • Remove excess air from packaging by compressing bag tightly.
  • Double bag powders before freezing.
  • Wrap bags tightly in plastic wrap to seal out air.
  • Store frozen powders in durable airtight containers.

But even with excellent packaging, freezer burn is hard to prevent entirely.

What About Refrigerating Protein Powder?

Refrigerating protein powder is generally safe, as long as moisture is kept out. The FDA recommends storing powders below 40°F.

Benefits of refrigeration:

  • Slows protein denaturation from heat and air exposure.
  • Retains flavor and aroma compounds longer.
  • Extends shelf life beyond room temperature storage.

Recommendations for refrigeration:

  • Keep powders in airtight containers to prevent moisture absorption.
  • Don’t open container repeatedly as moisture will accumulate.
  • Allow refrigerated powder to come to room temperature before using.

Overall, refrigeration preserves powders better than room temperature. But freezing still causes too much damage.

Signs Your Protein Powder Was Frozen

If you suspect a protein powder may have been frozen, here are some signs to look for:

Appearance Texture Taste
Clumped granules Gritty, sandy Flat, bland
Layer separation Chalky, dry Metallic, chemical
Dry, shriveled clumps Gummy, sticky Stale, oxidized
Crystals or ice specks Foams poorly Loss of sweetness

If a powder displays any of these traits, it has likely been compromised by freezing. It’s best to discard it and buy a new batch.

Can You Fix Frozen Protein Powder?

Unfortunately, there is no good way to reverse freezing damage once it has occurred:

  • Microwaving will further denature proteins and damage nutrition.
  • Heating below 150°F does not destroy large ice crystals or thaw emulsifiers.
  • Vigorous shaking cannot reblend separated ingredients.
  • Stirring in liquids doesn’t dissolve clumps or improve solubility.

The particles and structures in frozen powders undergo permanent changes. For best results, throw away frozen powder and buy a new package stored properly.

Best Storage Practices

Here are tips for storing protein powder to avoid freezing and maintain freshness:

  • Keep unopened protein in a cool, dry pantry away from heat sources like ovens.
  • After opening, transfer to an airtight container and store in refrigerator.
  • Keep scoop separate from powder to limit air exposure each time you scoop.
  • Write the opened date on container and use within 2-3 months.
  • Don’t store opened powders at room temperature as heat and humidity degrade them.
  • Check for clumping, off-odors, separation, and other signs powders have spoiled.

Following best practices preserves your investment in protein supplements.

The Bottom Line

Freezing protein powder fundamentally alters its properties through protein denaturation and ingredient separation. These structural changes cannot be reversed. While refrigeration can extend shelf life, the freezing point must be avoided.

For best quality protein with optimal nutrition, taste, and mixability – store your protein properly. Keep powders sealed in a cool, dry place without freezing. Follow the manufacturer’s recommendations, and your protein supplements will remain stable so you can fuel your fitness goals.

Now you know why those protein tubs advise against freezing! Proper storage keeps powders fresh and effective.

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