How do you know if cookware is stainless or aluminum?

Answer 1

I was one of the people who had this question and since it wasn't answered yet, I dug for my own answers. This is what I've found.

Short answer: A Stainless Steel pot or pan is in many ways better than an aluminum pan, even though aluminum conducts heat better.

Expanded answer: Stainless Steel is one of the best "non-reactive" materials used in cookware. Aluminum is a reactive material which will change the way foods that are made in it look and taste. There are many arguments that aluminum cookware can cause health issues, but from what information I have found, aluminum cookware is safe for use as long as you avoid cooking acidic foods for long periods of time in them. It's also suggested that you don't store acidic food in aluminum pots and pans. Anodized Aluminum is safe to cook acidic foods in as long as there are not any pits and scratches on the surface.

Generally, a Stainless Steel pot will last much longer (sometimes generations) than an aluminum pot. No matter how many scratches and pits the Stainless Steel pot gets it'll always remain non-reactive, so you can cook any type of food in them. For these reasons, I say yes, a stainless steel pot is better than an aluminum one.

Answer 2

With a magnet. Aluminum is not magnetic. That is of course dependent on the steel. All aluminum is non magnetic, however so are some types of steel. The degree of magnetic response or magnetic permeability is derived from the microstructure of the steel.

A totally non-magnetic material has a magnetic permeability of 1. Austenitic structures are totally non-magnetic and so a 100% austenitic stainless steel would have a permeability of 1. In practice this is not achieved. There is always a small amount of ferrite and/or martensite in the steel and so permeability values are always above 1. Typical values for standard austenitic stainless steels can be in the order of 1.05 - 1.1. It is possible for the magnetic permeability of austenitic steels to be changed during processing. For example, cold work and welding are liable to increase the amount of martensite and ferrite respectively in the steel. A familiar example is in a stainless steel sink where the flat drainer has little magnetic response whereas the pressed bowl has a higher response due to the formation of martensite particularly in the corners. In practical terms, austenitic stainless steels are used for "non-magnetic" applications, for example magnetic resonance imaging (MRI). In these cases, it is often necessary to agree a maximum magnetic permeability between customer and supplier. It can be as low as 1.004. REF: http://www.bssa.org.uk/faq.php?id=24 (British Stainless Steel Association)

Answer 3

Cast iron is much heavier than cast aluminum. A magnet or compass needle will be attracted to cast iron, but will not be attracted to cast aluminum. Cast iron quickly develops a dark coating of iron oxide (rust) after being exposed to humid (damp) air and will continue to rust if left exposed, while cast aluminum becomes coated with an amost invisible whitish layer of aluminum oxide that protects it fom further oxidization. Cast iron is somewhat difficult to scratch compared to scratching the much softer cast aluminum.

Answer 4

Stainless steel is a very poor conductor of heat. Stainless steel pans have a layer of aluminum clad or bonded to it, usually in a sandwich layer. Inexpensive stainless pans have this layer only on the bottom and you can see the difference in thickness. Higher end cookware, such as All-Clad , have three layers of metals on the bottom of the pans and up the sides as well. The conductive layer is usually aluminum, but it can also be copper. The cooking surfaces of stainless pans are free of aluminum so that they are non-reactive.

Answer 5

Stainless steel is durable, heavy, doesn't have chemical reaction with food while aluminum clad cookware is lightweight, easily to scratch and has chemical reaction with acidic food. Stainless steel cookware has poor heat conduction unless it is sandwiched with aluminum or copper while aluminum cookware heats up quickly. Stainless steel cookware tends to be more expensive than aluminum clad cookware.