Do you have a pot, pan, or utensils that are starting to show signs of rust? The question is: should you throw them out or can you redeem them? Here I look at the cause of rusty pots and kitchen pieces, and what to do.
Why do pots and pans rust? (Or other kitchen gear for that matter)
You might be wondering if your rusty pots or kitchen goods should be thrown out or not. Let’s start with why they rust…
Pots and pans and utensils can rust with age and exposure to the elements. These elements are water and oxygen, which combine with the third element, iron, to form rust — a reddish-orange layer on the surface of the cookware.
It’s a process called oxidation, where oxygen molecules interact with the metal to create rust. The chromium in food grade stainless steel prohibits this rust forming. Good stainless steel pans may discolor (which you can fix) — they don’t rust.
Not all pots and pans (or utensils) made of metal, rust. It depends on the material of which they are made.
Copper doesn’t rust but loses it’s shiny copper color with oxidation, turning greenish-brown and dull. Most modern copper cookware is lined with tin to avoid this occurring. But if your copper cookware has this oxidized discoloration, it’s not safe to use. Clean and polish to restore it.
Note: Never use copper cookware with acidic ingredients as the copper reacts with acidic foods to form this verdigris, a greenish pigment that’s toxic if ingested.
Also, while our bodies need a certain amount of copper, too much can be toxic.
Aluminum can corrode forming a whitish residue with oxidation (I would definitely discard the pot or pan). I wrote about the concerns with aluminum in my post covering the different types of cookware material.
Pots and pans containing iron are those that rust. Utensils made of ordinary steel can rust.
Stainless steel contains chromium to prevent oxidation, but if it’s of poor quality composition it can show signs of rusting (I would discard in this case).
Cast iron cookware can rust if left unseasoned or where chipped (if it’s the enamelled type). But you can treat it. It is salvageable!
What can escalate rust forming:
- Incomplete drying of the goods before storing;
- exposure to the weather, if used with an outdoor grill and stored outdoors (for example);
- erosion of the surface sealing; and
- exposure to acid.
Acidic ingredients include, wine, citrus, tomatoes, and vinegar-based sauces.
Is it safe to use a rusty pan
When deciding whether or not it is safe to use a rusty pot, consider the following questions.
1. Is the pan still structurally sound?
2. Does it have any holes or cracks that could cause hot liquid to leak out while cooking?
3. What material is it made of? Is it made of cast iron? Can I clean and restore it?
Cast iron can can be treated to remove rust and prevent rust from recurring. Anything else, you may want to consider throwing it away (although you can restore copper by cleaning and polishing it to remove the harmful dull layer).
Can you get sick from rusty cast iron pans?
Rusty cast iron pans will leach iron into foods you are preparing. The iron itself may not make you sick, as iron is an essential element required in our diets, for instance, for healthy blood cells.1 But there’s a possibility the rust layer may contain other particles that will contaminate your food and which may pose a risk.
In any case, the added iron will probably ruin the flavor of your meal. It’s best, before going ahead and using it, to clean off the rust and season the cast iron pan to seal it — see my article on seasoning cast iron pans.
- University of California: Iron Requirements