A variety of materials are used to manufacture cookware.  The surface of your cookware impacts both the resulting taste of your food and its safety related to the amount of metal that leaches into your food. Cooking materials give off atoms and molecules when heated and when immersed in acidic or alkaline solutions.  To appreciate the ease and safety of surgical stainless steel as a cooking surface, let’s look at various cookware materials and evaluate the dangers of releasing or leaching those materials into your foods.

Aluminum Cookware:

Aluminum is an excellent heat conductor but it’s also a fairly soft metal that leaches more molecules into food than harder metals used in other cookware. As a soft metal it is prone to scratching and it warps easily at high heats. A major health drawback to aluminum is that it is a reactive material. This means that it will react with acidic foods such as citrus and tomatoes, and also with alkaline foods such as cabbage and asparagus. The reaction causes foods to have an off, metallic taste, and also causes color changes in the foods, making them appear an unattractive grey shade. But, more importantly, foods cooked in aluminum can react with the metal to form aluminum salts. There are some theories that this is a contributing factor in the increase of Alzheimer's disease but this has not been proven.

Manufacturers have addressed aluminum leaching by anodizing the cookware. Through anodization, chemical baths are used to increase the thickness of the oxide layer making it harder, more durable, less likely to corrode and less likely to leach, provided the surface has not been damaged. Although it is more difficult to damage the surface of anodized versus non-anodized aluminum, its surface can still be damaged.

A key purchasing consideration is that not all cookware in the marketplace using anodized aluminum uses this material on the surface that comes in contact with food.  Instead they use the heat transfer properties of the anodized aluminum on the exterior of the cookware and a different non-stick surface on the interior of the cookware (with other potential toxicity problems much greater than anodized aluminum).

From an environmental perspective, aluminum can not be destroyed in the environment, it can only change form.  The Environmental Protection Agency has found aluminum in at least 596 of the 1,699 National Priority List sites.

Cast Iron Cookware:

Cast iron cookware has been in use for nearly 3,000 years (since it was first used in China to cook rice). It is strong, inexpensive and has excellent heat conducting capabilities for browning, frying and baking. Dangerous metal leaching is not an issue with cast iron cookware.  Iron is known to leach into the food with cast iron cookware once being a major source of iron in food. Since cast iron cookware is less prevalent it is thought to be a reason people sometimes need iron supplements. Iron toxicity is usually not a problem, except in children under the age of five years.

The downsides to cast iron cookware are that it is heavy, it must be seasoned for use, it is difficult to clean, it can rust and it can harbor bacteria. To prevent rust damage, the inside of cast iron cookware should be coated frequently with unsalted cooking oil, it should be dried thoroughly after each use and it should be stored with the lid off.  To prevent bacteria growth, it must be cleaned thoroughly after each use.  However, it can not be immersed in water and you should not use strong detergents or scour the cookware as each of these can cause damage to seasoning on the cookware.  

Teflon / Non-stick Cookware:

Teflon’s non-stick surface is the reason many people buy it. Yet, it is hazardous to our health.  Not just from the chipping and flaking but from the fumes.  When non-stick pans are heated to high temperatures, the coating breaks down and vaporizes, releasing toxic substances into the air.  Perfluorinated acid (PFOA) is used in the manufacture of non-stick pans.  It is not present in the pans themselves, but can reappear in the fumes when pans are overheated and the coating decomposes. It has been shown in many studies that PFOA accumulates in the body and in the environment.  Studies on animals suggest a link to birth defects. According to the National Resource Defense Counsel, Dupont, the maker of Teflon, admits the fumes contain PFOA but claims that temperatures must exceed 500 degrees Fahrenheit for ‘deterioration to occur’ and 660 degrees for ‘significant decomposition’…Non-stick pans do get that hot when preheated on high – a practice many cooks follow.  It doesn’t take much time either for temperatures to climb.  In tests conducted on ordinary gas and electric stoves, Teflon and other non-stick pans topped 700 degrees Fahrenheit in three to five minutes. 

Teflon and other similar non-stick coatings can be convenient and safe when used to cook on low – moderate heats such as with non-stick griddles.  High heat cooking must be avoided.

Copper Cookware:

Copper is beautiful cookware and has excellent heat conducting capabilities.  However, the cooking surface must be lined with a safe substance such as stainless steel. The FDA cautions against using unlined copper for general cooking because the metal is relatively easily dissolved by some foods with which it comes in contact and, in sufficient quantities, can cause nausea, vomiting and diarrhea.

The toxic effects of copper are well documented. A classic case reported by the New York Department of Health in the 1970s explores the dangers of unlined copper.  Children attending a movie matinee bought soda from the type of vending machine that drops a cup and fills it with carbonated water from one side and syrup from another. The check valve for dispensing the carbonated water was made of copper. Overnight, a significant amount of copper had dissolved into the carbonated water. The children became ill from drinking the soda contaminated with copper salts.

Pyrex:

Pyrex has an extremely low transfer rate of molecules but it only can be used in the oven and not on the stove top.

Stainless Steel Cookware:

Stainless steel itself is not a good heat conductor.  To be efficient cookware, it needs layers of other metals in its inner construction.  Without those inner layers, stainless steel cookware will heat food unevenly.  High grade stainless steel as the outer layer, in contact with food, is easy to clean and will not harbor bacterial and germs.  Stainless steel that has been cleaned and scoured with a metallic pad may leach a small amount of nickel into the food, when exposed to alkaline food.  Nickel is not poisonous but people with nickel allergies should avoid cooking with stainless steel.

Cookware Demonstrations

The above evaluation would not be complete without addressing some of the cookware demonstrations you may see.  It’s always a good idea to evaluate your cookware for pitting, deep scratches, and flaking.  However, you may be exposed to the following cookware tests:

1.  The Baking Soda Taste Test

A common demonstration for stainless steel waterless cookware is to heat baking soda and water in various pots, including the brand being sold. Often cheap aluminum cookware (which is likely to leach higher quantities of aluminum) is used for the demonstration. When the customer tastes the water from the other cookware, a strong metallic taste it noticed. On the other hand, the water from the demonstration stainless steel cookware simply tastes like baking soda.

As noted above, baking soda in water is highly alkaline and reacts with aluminum.  This creates the metallic taste in cookware with an aluminum cooking surface. Baking soda also reacts somewhat in iron pots, but it does not react with new stainless steel.

Sometimes customers will be asked to include their own stainless steel cookware in the test. Stainless steel cookware that has been scoured with steel wool will have small scratches that allow nickel to react with the alkaline baking soda solution. This implies that the brand for sale is superior to their own stainless steel cookware. 

The demonstration is dramatic but it functions here as a sales tool for new stainless steel cookware. Most foods are not as highly alkaline as baking soda so the metals leaching from the cookware would not react as severely with the foods being cooked.  

2. The Hot Spot Sugar Test

This test is useful in evaluating hot spots in your cookware.  Gas and electrical stoves do not uniformly spread the heat source over the pan’s bottom.  As noted above, different cookware material has different heat conducting capabilities.  When your cookware does not evenly distribute the heat source, food scorching will occur. Quality waterless cookware relies on the heat transferring capabilities of its cookware to cook food efficiently on low heats.

To check the heat transferring capabilities of your cookware, preheat your stove to medium low.  Coat the cookware evenly with a cooking spray then lightly coat the cookware with sugar.  Pour off the excess sugar the center the cookware on the preheated burner. 

Watch where the sugar melts across the pan and look to see if it starts to burn anywhere.  Where it burns will be the hot spots on your cookware.  High quality waterless cookware should melt the sugar evenly with no hot spots.