Steel Pan Rust: Myth Or Reality?

Despite the name, stainless steel isn't entirely immune to rust. While it's certainly resistant to rust and corrosion, it's not entirely stainless. Stainless steel pans can become discoloured, burned, and covered in residue and food bits with consistent use and without proper care. One of the key components of stainless steel is chromium, which when oxidised, creates chromium oxide—a protective barrier against rust, corrosion, and staining. However, this barrier can be damaged by metal cookware, harsh detergents, or other elements, exposing the metal to oxygen and water, which causes rust to form. Pans with a lower chromium percentage are more vulnerable to rust, so it's recommended to opt for a higher percentage, such as an 18/10 ratio of chromium to nickel.

Stainless steel pans are fairly rust-resistant

The chromium oxide barrier can be damaged by harsh detergents, metal utensils, or other elements, exposing the metal to oxygen and water, which causes rust to form. Pans with a lower chromium percentage are more vulnerable to rust, so it is recommended to opt for a higher percentage, such as an 18/10 ratio of chromium to nickel.

Additionally, certain conditions can accelerate rusting. For example, stainless steel pans can easily rust in salty and moist environments, especially if left unwashed with salty water that dries out. Acids can also cause rusting.

To prevent rust, it is important to properly care for your stainless steel pans. Always dry your pans immediately after washing them, using a soft dish towel or microfiber cloth. Avoid air drying as this can lead to water spots and increase the risk of rusting if the pan is scratched. If stacking your pans, place a protective layer between each pan to prevent scratching.

While stainless steel pans are fairly rust-resistant, proper care and maintenance are necessary to prevent rust and ensure the longevity of your cookware.

Pans with a lower chromium percentage are more vulnerable to rusting

While stainless steel is known for its resistance to rust, it is not entirely rust-proof. The inclusion of chromium in stainless steel is what makes it resistant to rust. When chromium oxidizes, it creates chromium oxide, which forms a protective barrier against rust, corrosion, and staining. However, pans with a lower chromium percentage are more vulnerable to rusting.

The minimum chromium content in stainless steel is 10.5%. The higher the chromium content, the less likely the metal will rust. For example, the most common type of stainless steel, 304, has a chromium content of 18%. Increasing the chromium content to more than 11% can further increase corrosion resistance. Additionally, adding nickel to at least 8% and molybdenum can also improve resistance to pitting corrosion.

Pans made of stainless steel with a lower chromium percentage are more susceptible to rust, especially when exposed to certain conditions. For instance, stainless steel can rust when exposed to salty and moist conditions or acidic substances. Boiling dry with salt in the water, leaving salty water to dry in the pan, or adding salt to cold water before boiling can all lead to rusting or pitting in stainless steel cookware.

To prevent rust on stainless steel cookware, it is important to properly care for and maintain the pans. This includes drying the pans immediately after washing, using soft dish towels or microfiber cloths, and avoiding harsh detergents or abrasive scouring pads that can damage the finish. It is also recommended to stack pans with a protective layer in between and to clean the cookware after each use.

Salt is a common cause of rusting

Stainless steel pans are generally resistant to rust, but they are not entirely rust-proof. One of the most common causes of rust on stainless steel pans is salt. Salt can cause rusting even if the pan is not completely submerged in water, as increased moisture in the air and salt spray can provide the necessary conditions for rust to form.

Salt water does not make a metal rust, but it does accelerate the rusting process. This is because salt water is an electrolyte solution, which means it contains more dissolved ions than fresh water. Electrons can move more easily in salt water, and since rusting is the result of the movement of electrons, iron rusts more quickly in salt water than in fresh water.

There are several ways in which salt can cause stainless steel pans to rust. One way is if salt is left on the pan after cooking. For example, if you boil pasta in salted water, and then leave the pot unwashed and allow it to dry, this can cause rust spots to form. Similarly, if you add salt to cold water in a stainless steel pan and then heat it up, this can also lead to rusting. The best way to avoid this is to only add salt to water once it has come to a boil.

Another way that salt can cause rusting is if a stainless steel pan is left unwashed with salty water residue and then dried. This can happen if you do not properly clean your cookware after each use, or if you leave a wet stainless steel pan in the dishwasher, as this can lead to water spots and provide an environment for rust to form. To prevent this, always hand wash your stainless steel pans with hot water, dish soap, and a soft dish towel, and dry them immediately by hand.

By understanding the role of salt in causing rust, you can take the necessary precautions to prevent rusting and keep your stainless steel pans in good condition.

How to clean rust spots off stainless steel pans

While stainless steel is fairly resistant to rust, it is not completely rust-proof. If you notice rust spots on your stainless steel pans, there are several methods you can use to clean them. Here is a step-by-step guide:

The Baking Soda Method:

• Make a thick paste by mixing baking soda with water.
• Apply the paste generously to the rusted areas of your pan.
• Let the paste sit for a few hours or overnight for better results.
• Using steel wool, a scouring pad, or a wire brush, scrub the paste in a circular motion to remove the rust.
• Rinse the pan with water and dry it completely to prevent new rust from forming.

The Vinegar Method:

• Submerge the rusty pan in white vinegar, ensuring it is completely covered.
• Let the pan sit overnight. The acetic acid in vinegar breaks down rust, making it easier to scrub off.
• Rinse the pan with water and dry it completely.

The Lemon Juice and Salt Method:

• Sprinkle salt over the rusted area.
• Squeeze lemon juice over the salt.
• Allow the mixture to sit for a few hours, as the acid in the lemon juice reacts with the rust.
• Use a scouring pad or brush to scrub away the rust.

The Potato and Dish Soap Method:

• Cut a potato in half and dip the cut end in dish soap.
• Rub the potato over the rusted area. The oxalic acid in the potato helps break down the rust.
• Let the juice sit for a few hours before rinsing.

Commercial Rust Removers:

Commercial rust removers are also an option for stubborn rust. Always follow the manufacturer's instructions and wear protective gear when using these products.

Sandpaper for Severe Rust:

For severe rust that has deeply penetrated the metal surface, you may need to use sandpaper or a metal brush. Start with coarse-grit sandpaper to remove most of the rust, then switch to finer-grit sandpaper to smooth the surface.

Tips to Prevent Rust:

• Always dry your pans immediately after washing.
• Stack pans with a dish towel, trivet, or other protective layer between them to prevent scratching.
• Properly clean your cookware after each use.
• Avoid air-drying as it can lead to water spots and scratches, making the pan more susceptible to rust.
• Only add salt to water after it has come to a boil.

How to prevent rusting on stainless steel pans

While stainless steel is resistant to rust, it is not completely rust-proof. To prevent rusting on your stainless steel pans, you should:

• Always dry your pans immediately after washing them with a soft dish towel or microfiber cloth. Never air-dry as this can lead to water spots and cause scratches that may result in rust.
• Place a dish towel, trivet, or other protective layer between pans if you stack them in a cupboard to prevent scratching.
• Invest in high-quality stainless steel pans made from 18/10 or 304 stainless steel. 304 stainless steel is commonly used and is fairly rust-resistant, but it will rust easily in salty and moist conditions. 316 stainless steel is more resistant to salt corrosion.
• Clean your pans properly after each use to prevent dried and burnt food from building up, and to ensure the surface is ready for polishing.
• Polish your pans to keep the chromium oxide layer intact. This layer is what prevents the pans from rusting.
• Only use soft sponges to scrub your pans. Avoid harsh dish scrubbers or abrasive scouring pads, as these can damage the finish.
• Avoid using steel wool, hard metal brushes, or abrasive cleaners on your pans, as these will make them more susceptible to corrosion.
• Avoid using the dishwasher to clean your pans, as the detergent may harm the finish and cause spotting.
• Only add salt to water once it has come to a boil to prevent a form of rusting called "pitting".

Frequently asked questions