What’s Really in Your Salt?

Anti-Caking Agents, Table Salt Additives, and Why Natural Salt Clumps

Salt is one of the oldest ingredients in human history -- used for nourishment, preservation, and even ceremonial purposes across cultures. Yet many modern grocery store salts contain more than just sodium chloride.

If you’ve ever wondered what is actually in table salt, the answer may surprise you.

Many commercial salts contain anti-caking agents: additives designed to keep salt perfectly dry and free-flowing. While these ingredients make salt easier to package and pour, they also mean that the product in the shaker may not be as simple as it appears.

Understanding anti-caking agents in salt can help you make more informed choices about the salt you use every day.

Why Table Salt Pours So Easily

If table salt always seems to flow smoothly, even on humid days, that consistency isn’t accidental.

In the early 1900s, salt manufacturers began adding special compounds to prevent clumping caused by moisture. One of the most famous marketing slogans in American food history came from Morton Salt, which promised consumers that their salt would pour easily even in rainy weather.

This effect is achieved through the addition of anti-caking agents.

These additives keep salt grains from sticking together, ensuring that salt flows freely both in manufacturing facilities and in kitchen shakers.

What Are Anti-Caking Agents in Salt?

Anti-caking agents are substances added to powdered or granular foods to prevent particles from sticking together.

They are commonly used in:

• table salt

• powdered sugar

• baking mixes

• spice blends

• powdered drink mixes
  

These compounds work in two main ways:

Moisture absorption: Some additives attract and absorb water molecules that would otherwise cause salt crystals to clump.

Particle coating: Other agents coat the salt grains so they slide past each other more easily.

For large-scale food manufacturers, this helps salt move smoothly through machinery, prevents production delays, and keeps the final product visually uniform.

Common Salt Additives Used as Anti-Caking Agents

Several compounds are commonly added to table salt to keep it flowing freely. Some of the most frequently used include:

Calcium Silicate (E552): A mineral-based compound that absorbs moisture and helps prevent clumping.

Silicon Dioxide / Silica (E551): A fine powder used to coat particles and reduce friction between salt crystals.

Sodium Ferrocyanide (E535): Sometimes called yellow prussiate of soda, this compound stabilizes salt in humid environments.

Sodium Aluminosilicate (E554): A mixture containing aluminum and silicon that reduces moisture absorption.

Tricalcium Phosphate (E342): Another anti-caking compound occasionally used in powdered foods.

Although these additives are approved for use in food products, their presence means that many commercial salts are not simply pure salt.

Are Anti-Caking Agents Safe?

Food safety authorities generally consider anti-caking agents safe at the small concentrations used in food production. However, some researchers and nutrition writers have raised questions about long-term exposure to extremely fine particulate additives.

Biologist and nutrition researcher Ray Peat referenced earlier research by German physician Gerhard Volkheimer on a phenomenon known as persorption.

This research suggested that very small particles may occasionally pass through the intestinal wall and enter the bloodstream. In some studies, microscopic particles were later detected in blood, urine, and various tissues.

While the implications of this process remain debated, some researchers believe that persistent exposure to certain fine particles may contribute to inflammatory responses in the body.

Another topic sometimes discussed involves aluminum-containing additives such as sodium aluminosilicate. When exposed to digestive conditions, small amounts of aluminum ions may be released. Although typical dietary absorption is low, elevated aluminum exposure has been studied in relation to neurological conditions, bone health, and kidney function.

Sodium ferrocyanide (E535) has also raised curiosity among consumers because it contains cyanide molecules bound to iron atoms. In normal food conditions the compound remains stable and non-toxic, but in highly acidic environments it can theoretically release hydrogen cyanide gas. In food applications the compound is used in extremely small amounts.

Why Natural Salt Sometimes Clumps

If you’ve ever purchased a natural or mineral salt and noticed that it clumps more easily than table salt, this is usually a sign that the salt contains no anti-caking additives.

Natural salts often retain trace minerals such as:

• magnesium

• potassium

• calcium

These minerals can attract moisture from the air, a property known as hygroscopicity.

Because of this, natural salts may:

• form small clumps in humid environments

• feel slightly softer or denser than processed table salt

• require occasional shaking or crushing

This natural behavior is one of the easiest ways to recognize unprocessed mineral salt.

The Cleo Salt Approach

At Cleo Salt, we believe salt should remain as close to its natural state as possible.

Our salts are selected for their purity and mineral integrity, without the addition of anti-caking agents or unnecessary processing.

Because of this, you may occasionally notice clumping -- especially in humid conditions. Rather than viewing this as a flaw, we see it as evidence that the salt has not been chemically treated to force it into a perfectly free-flowing texture.

A quick shake or gentle crush between your fingers will easily restore the grains.

For us, preserving the simplicity of pure mineral salt is worth far more than cosmetic perfection.

Final Thoughts: Choosing a Cleaner Salt

Salt may seem like a simple pantry staple, but modern processing has changed what many people are actually consuming.

Learning about salt additives, anti-caking agents, and natural mineral salts can help you decide which type of salt best aligns with your values and health priorities.

Sometimes the most natural choice is also the simplest one.

Sources

Morton Salt. Company history and product development archives.Peat, R. Research on food additives and biological effects. Volkheimer, G. Studies on persorption and particle absorption in the digestive system. Food Additives Database. Information on anti-caking compounds used in food production. Toxinless. Comparative analysis of salt additives and processing methods.