Even after cleaning, rainbow streaks often appear on the bottom of stainless steel pots and pans. What are they, and are they harmful to human health?
Rainbow streaks, also known as multicolored stains, are commonly found on the bottoms of stainless steel cookware. Even after washing, they can remain, causing confusion among many home cooks. They wonder if these streaks are a sign that their cookware is contaminated or if they result from the use of cheap, low-quality materials. Could these rainbow streaks impact health?
Rainbow streaks are often found on the bottoms of stainless steel cookware. (Photo: Times of Malta).
According to Times of Malta, this is a completely normal phenomenon. It does not affect the quality of food or the health of users of stainless steel cookware. Scientists have named these rainbow streaks the “heat tinting phenomenon.”
The cause is that stainless steel cookware is typically made from stainless steel. This type of steel usually contains a small amount of chromium to prevent rust and corrosion. When chromium comes into contact with air, it forms a protective layer.
Scientists have named the rainbow streaks the “heat tinting phenomenon.” (Photo: Times of Malta)
Stainless steel, when heated to high temperatures, causes the oxidation layer to thicken, resulting in rainbow streaks. This phenomenon can also occur at high temperatures, helping the cookware heat up quickly. This layer of rainbow streaks protects the stainless steel pots and pans and is not harmful to human health.
Many people question whether chromium is toxic, but in reality, chromium is very difficult to oxidize in its Cr6+ state (the compound that is toxic). While it is not harmful, many believe that the rainbow streaks detract from the aesthetic appeal of their cookware. Users can use vinegar to clean these stains.
There are two methods to remove rainbow streaks from stainless steel cookware.
Using lemon can help remove rainbow streaks from stainless steel cookware. (Photo: Times of Malta)
Method 1: Mix white vinegar with water in a 1:5 ratio and pour it onto the stained area, letting it sit for 10-15 minutes. Alternatively, you can use a sponge soaked in vinegar to gently scrub the rainbow stains. Afterward, rinse with water and dry the pot.
Method 2: Use half a lemon to rub directly on the colored streaks, then rinse with water.
