How do you know if salt is non-iodised?

December 31, 2025 •

4 min read

In many countries, salt is fortified with iodine to prevent deficiency disorders, making non-iodised options a specific choice for certain culinary or dietary needs. This guide details how you know if salt is non-iodised, covering everything from scrutinizing product labels to simple kitchen science experiments to confirm its composition.

Quick Summary

Identifying non-iodised salt involves checking product labels for explicit declarations and recognizing the characteristics of specific salt types, like kosher or sea salt. A simple home test using starch can provide confirmation, highlighting important differences for culinary and dietary purposes.

Key Points

Check the label: The most reliable method is to read the packaging for "non-iodised" or to check the ingredients list for added iodine compounds.
Observe texture and appearance: Many specialty salts like coarse kosher, flaky sea salt, and pink Himalayan salt are naturally non-iodised and have distinct grain sizes and colors.
Perform a starch test: A simple home test with starch, vinegar, and hydrogen peroxide will cause an iodised salt solution to turn blue-purple.
Note culinary uses: Non-iodised salt is often preferred for canning and pickling to avoid discoloration, or for brining where a specific texture is desired.
Taste test with caution: Some individuals can detect a slightly metallic taste from iodised salt, though this is subjective and not a definitive test for all.
Consider dietary needs: Individuals on low-iodine diets, often for thyroid-related reasons, must use non-iodised salt as directed by their doctor.
Understand the health implications: Non-iodised salt lacks the beneficial iodine used to prevent deficiency, so ensure you get iodine from other dietary sources if you opt for it.

The Easiest Method: Checking the Label

For most packaged salt products, the quickest and most reliable way to determine if it is non-iodised is to read the packaging carefully. Manufacturers are required to label their products accurately, especially regarding a nutrient as significant as iodine. On iodised salt, the label will prominently state "iodised salt". Conversely, non-iodised products will be labeled as "non-iodised," or they will list the ingredients without any mention of potassium iodide, sodium iodide, or potassium iodate. For specialty salts, the packaging may simply list "salt" or specify the salt type without any fortification claims. Always double-check the ingredient list for full transparency.

Visual and Textural Clues

The physical characteristics of salt can often hint at whether it is iodised or not, though this method is less foolproof than reading the label. Refined table salt is typically fine-grained, uniformly white, and often includes anti-caking agents. This is the salt most commonly fortified with iodine. Non-iodised salts, particularly gourmet varieties, tend to differ significantly in appearance and texture. Here are some examples:

Kosher Salt: Features large, coarse, and flat grains. Its texture makes it easy to pinch and sprinkle accurately. It is typically free of iodine and anti-caking agents.
Sea Salt: Can vary widely from fine to coarse grains, depending on how it was harvested from evaporated seawater. It often retains trace minerals that give it a unique flavor and may or may not be iodised.
Himalayan Pink Salt: Characterized by its distinctive pink hue, caused by trace minerals like iron oxide. Mined from ancient salt deposits, it is naturally non-iodised.
Pickling Salt: A highly refined salt without anti-caking agents or iodine, specifically formulated for canning and preserving foods without affecting their color or causing cloudiness.

Taste Differences for the Discerning Palate

Some individuals with sensitive palates claim to detect a slight metallic or chemical taste in iodised salt, especially in large quantities. This is due to the presence of the iodine compound. Non-iodised salts, by contrast, offer a clean, pure saline taste that allows other flavors in a dish to shine. However, this is a subjective method and not a reliable indicator for everyone, particularly when the salt is dissolved into a recipe.

The At-Home Starch Test for Confirmation

For a conclusive at-home test, you can use a simple chemical reaction involving starch. When iodine (specifically iodide, the form added to salt) is exposed to starch in an acidic environment, it causes a distinctive blue-purple color change.

Materials:

Clear disposable cups
Salt samples
Distilled water
White vinegar (for acidity)
Hydrogen peroxide (to convert iodide to iodine)
Laundry starch solution or liquid cornstarch solution
Plastic spoons

Procedure:

Label each cup for the salt you are testing.
Add a teaspoon of salt to each cup.
Pour a cup of distilled water into each cup and stir to dissolve the salt.
Add a tablespoon of white vinegar to each mixture.
Add a tablespoon of 3% hydrogen peroxide.
Stir in about half a teaspoon of liquid starch.
Wait a few minutes. If the salt is iodised, the solution will turn blue-purple. If it remains clear, the salt is non-iodised.

Comparison of Iodised and Non-Iodised Salts


Feature	Iodised Salt	Non-Iodised Salt (e.g., Kosher, Sea)
Iodine Content	Contains added iodine (potassium iodide or iodate).	No added iodine.
Processing	Highly refined, with minerals typically removed.	Varies from minimally processed (sea salt) to refined (pickling salt).
Additives	Often contains anti-caking agents to prevent clumping.	Typically free of additives, especially specialty salts.
Appearance	Fine, uniform, white crystals.	Crystals can be coarse, flaky, or have distinct colors (e.g., pink Himalayan).
Flavor	Some may perceive a slight metallic aftertaste.	Offers a pure, clean saline taste.
Best For	General cooking, everyday use for iodine intake.	Pickling, canning, specific recipes requiring a clean taste or coarse texture.

When is Non-Iodised Salt Preferred?

Cooks and individuals often choose non-iodised salt for specific culinary and dietary reasons. In baking, for example, non-iodised salt is preferred for its pure flavor that won't interfere with delicate sweets. For canning and pickling, non-iodised salt ensures that the iodine does not discolor the preserved foods. Additionally, those following special dietary recommendations, such as a low-iodine diet for certain thyroid conditions, must strictly use non-iodised salt under a doctor's supervision. The different textures of salts like kosher or flaky sea salt are also desirable for brining or as a finishing touch on dishes to add a crunchy burst of flavor. To learn more about iodine's function in the body and recommended intake, consult resources like the NIH Office of Dietary Supplements.

Understanding the Health Context

While this article focuses on identifying non-iodised salt, it is crucial to remember the broader health context. Universal salt iodisation programs were implemented globally to combat iodine deficiency, a leading cause of preventable brain damage. Though many people get sufficient iodine from a varied diet, iodised salt remains a simple, effective source for those who might be at risk of deficiency. Neither iodised nor non-iodised salt is inherently healthier; both contain similar levels of sodium. The key is moderation and ensuring adequate iodine intake from diverse sources, unless specifically advised against by a healthcare provider.

Conclusion

Knowing how to identify non-iodised salt is a straightforward process that relies on careful inspection and, if necessary, a simple home test. Start by reading the product label, which is the most definitive method. Next, consider the salt's appearance and texture, recognizing that coarse, uniquely colored, or flaky salts are often non-iodised. For a conclusive check, the starch and vinegar test provides a clear chemical indicator. Whether for specific cooking methods like pickling or for dietary management, being able to confidently distinguish between iodised and non-iodised salt allows for more informed culinary and health choices.

Frequently Asked Questions

Sea salt is produced from evaporated seawater and can contain trace amounts of minerals, including iodine. However, it is not typically fortified like iodised table salt, and the amount of iodine is not sufficient to meet dietary needs.

It is not recommended to use iodised salt for pickling and canning. The iodine can sometimes cause the preserved foods to darken in color or alter their texture. Non-iodised pickling salt is the preferred choice for these applications.

No, neither is inherently healthier than the other, as both have a similar sodium content. The choice depends on dietary needs and culinary preferences. Non-iodised salt is for those who need to manage their iodine intake or prefer a specific texture or flavor.

Yes, you can perform a simple home test. Combine a salt sample with water, vinegar, and hydrogen peroxide, then add a liquid starch solution. If the mixture turns blue or purple, the salt contains iodine.

Some chefs prefer non-iodised salt, such as kosher or flaky sea salt, for its pure flavor, which some believe is cleaner than iodised salt. Its specific texture is also desirable for brining, seasoning, and as a finishing touch on dishes.

By weight, most salts, including iodised and non-iodised, contain roughly the same amount of sodium. However, coarse salts like kosher salt have larger crystals, meaning less salt fits into a teaspoon compared to fine-grained table salt.

The primary differences are grain size, additives, and iodine content. Kosher salt has coarse, flat grains and is typically non-iodised without anti-caking agents. Iodised table salt is finely ground, iodised, and often contains additives.