Understanding Cookware, Materials and finding the best Frying Pan

Introduction Cookware Materials

Before we jump right into understanding the different cookware materials out there, we recommend you having a quick read on the two basic principles underlying cookware materials. It offers a basic understanding that will be helpful for everything else that is to come.

 

Materials

Comparison of cookware materials stainless steel carbon steel iron copper aluminum along the most important criteria weight cost price design safety health used in fry pans, cookware pots

Comparison of cookware materials along the most important criteria used in fry pans, cookware pots

We will compare common cookware materials along the most important criteria to consider. These are:

 

  • Heat Diffusivity (ability to spread temperature)
  • Heat Capacity (ability to store heat)
  • Weight (density)
  • Food reactivity
  • Cost
  • Design

Note: A great heat capacity means that the pan has the ability to store a lot of heat. At similar conductivity, a pan with higher capacity stays hot for longer and has more energy stored to heat up a cold piece of meat before cooling down itself. However, it would also be less reactive to changes in temperature unless it has a very high conductivity (see copper)

 

So let’s take a more detailed look at the most common materials that are used in pots and pans:

 

Aluminum

Aluminum cookware pots and pans

Picture: thin aluminum cookware pots and pans

Properties: Aluminum is a relatively cheap, weak and low weight metal with good thermal conductivity. In addition, is not induction compatible on its own and reacts to food.

 

Manufacturing: Pure aluminum pans are usually casted. However, different casting methods exist to eliminate air inclusion and improve properties such as heat shock resistance.

 

Advantages:

  • Thermal diffusivity: Aluminum is the second-best cookware material in terms of spreading heat across the pan
  • Low weight: It’s very low density (2600 kg/m3 compared to e.g. 7900 kg/m3 of cast iron) gives aluminum a very low weight-per-unit-of-volume.
  • Low cost: Aluminum is the cheapest of all cookware materials

 

Disadvantages:

  • Low heat capacity gives the material less “power”
  • Reacts to food, especially acidic food, which makes it necessary to coat aluminum or to use a cladded construction
  • Aluminum is weak and tends to warp, especially when too thin or not casted correctly
  • Aluminum is not induction compatible

 

Technically it is relatively difficult to deduct the exact ability to store heat. However, aluminum’s overall ability to store heat is low to mediocre and should be slightly better than that of copper. Therefore, due to its low density and good conductivity, it reacts to changes in heat fast, even if not as fast as copper. In other words, aluminum allows for precise but not as precise cooking results as copper.

 

Copper:

copper cookware pots and fry frying pans

Picture: pure Copper cookware which is rarely used due to high cost and raction with food

Properties: Copper, like aluminum, is a relatively weak (a tensile strength about half that of mild carbon steel) but at the same time is a long lasting metal. In addition, copper has excellent thermal properties. Unfortunately, copper is a very expensive metal. It reacts with food and oxidizes quickly which is why it requires the right construction. When copper is exposed, a special treatment to keep its look and protect against sediments is required.

 

Manufacturing: The copper cookware raw material comes in sheets. These sheets are subsequently bonded with other materials. Then they are punched and subsequently deep drawn. Even though copper is relatively easily formed, handling it as part of a ply construction is particularly difficult and can only be achieved at high quality by a handful of manufacturers worldwide.

 

Advantages:

  • Thermal diffusivity: heats evenly and allows to control the heat. This is because copper spreads temperature across the pan 20% faster than aluminum, more than 500% faster than cast iron and up to 2800% faster than stainless steel
  • Heat capacity: Copper heats up and cools down faster (thermal diffusivity) than any other cookware material. At the same time, it stores a lot of energy. Therefore more energy is stored in a copper pan than for example in a aluminum pan. This means that it won’t cool out as quickly when cold food is placed in the pan.
  • Design: copper has a majestic, classy and warm look which is why it is a desired cookware to decorate traditional and modern kitchens across the globe. Our designers here at Olav have explored different ways that would allow exposing copper on a ply construction.

 

Disadvantages:

 

  • Weight: Coppers has the highest density among all cookware materials. It is 11% heavier than stainless or carbon steel, 13% heavier than cast iron and 340% heavier than aluminum.
  • Price: The high raw material price and the difficulty to manufacture copper cookware (read more here soon) drives price of copper cookware.
  • Food reaction: Copper requires regular attention to avoid toxic copper acetate which should never touch your food (read more about coatings here).
  • Copper is not induction compatible.

 

In Practice

For beginners as well as pro-cooks and home décor lovers, we believe it’s a great choice as long as it is purchased as part of a cladded copper core construction. This way its possible to profit from copper’s great diffusivity while eliminating most of its disadvantages. Copper as a material is also technically the best choice as it allows for precise heat control of your cooking.

 

Excursion: Conductivity is copper’s unrivalled strength. It conducts 1.7 times faster than Aluminum, 5 times faster than iron, 4.5 times faster than carbon steel and 25 times faster than commonly used 18/10 Stainless Steel. Even though copper comes at a high weight, its resulting thermal diffusivity (ability to spread temperature) is still the best among all cookware materials.

 

Stainless Steel:

stainless steel cookware pots and fry frying pans

Picture: stainless steel cookware

Description: Stainless steel is a steel enriched with nickel and chromium to increase corrosion resistance while making it durable, strong and easy to use. In order to increase its thermal properties, stainless steel is often combined with aluminum and sometimes even with copper. See construction types.

Manufacturing: unalloyed steel is enriched with nickel, chromium and other components. Similar to carbon steel, it is then formed into sheets out of which circular discs are stamped and deep drawn to form the final shape of the pan.

 

Advantages

  • Low food reactivity
  • High heat capacity
  • Great design as it is a shiny metal that can be exposed due to its corrosion resistance and low food reactivity.

Disadvantages

  • Low diffusivity
  • High weight

 

Excursion:

Stainless steel isn’t stainless steel. In fact, stainless steel comprises various alloying elements. Those depend on the specific grade and composition. Different alloys are responsible for different steel properties. Broadly speaking, stainless steel can be classified into three major groups: ferritic (and martensitic), austenitic and other duplex (and precipitation hardening) alloys. The different alloys distinguish themselves mostly in their strength, durability, corrosion resistance, ability to shine and induction compatibility.

 

Below is a short summary of the most important alloying additions and their reason for presence:

 

Nickel: added to increase corrosion resistance. Furthermore, it’s the reason why polished steel is shiny and not dull, it increases formability, welding properties and delays the risk of cracking when a pan is deep drawn. However, nickel decreases magnetic properties and therefore reduces induction compatibility. For more information, see here.

 

Chromium: chromium is added to steel to increase resistance to oxidation. The more chromium, the better resistance to oxidation. SS has a minimum of 10.5% Chromium.

 

Molybdenum: Molybdenum is another expensive raw material that can increase corrosion resistance.

 

Titanium: Titanium can increase the carbide stabilization which is important when the material is welded. Adding 0.25-0.6% titanium cause the carbon to combine with titanium instead of chromium which ultimately minimizes the risk of inter-granular corrosion. However, as modern steel possesses less carbon, the use of titanium significantly decreases.

 

What becomes apparent is that, as so often in cookware, no stainless steel option has it all. If we prefer very corrosion resistant and shiny, high nickel grade alloys, we need to trade it for induction compatibility. However, there are ways in between which are suitable for a great everyday pan.

 

Cast Iron

enameled cast iron cookware pots and fry frying pans

Picture: enameled cast iron fry pan

Description: Cast iron is made of iron, carbon (more carbon than carbon steel, above 2.06%) and a low proportion of other materials.

 

Manufacturing: Metal is heated and casted into the final shape to cool down. A detailed description of the process can be read here.

 

Advantages:

  • Cost effective raw material and production
  • Great look, even if less modern and noble touch. The look can be enhanced through an enamel coating.
  • High heat capacity

Disadvantages

  • Thermal diffusivity is low. This results in heat spots during long warming-up period
  • Cast Iron skillets are very heavy
  • Prone to corrosion if not treated properly

Due to their high heat capacity and low conductivity, cast iron skillets have a great ability to store heat. Therefore, they stay hot for long after being removed from the heat source and don’t cool down quickly if filled with cold food. On the other hand, cooking a sauce on point or not-burning your simmering onions is practically impossible.

 

Cast Iron skillets require significant attention and work. The pan requires regular seasoning (which can be a relatively dirty process) and regular coating. Cast iron pans are not dishwasher safe and should be cleaned without detergent.

 

Carbon Steel

Description: Carbon steel contains less carbon than iron. The concentration of carbon is somewhere between 0.6 and 2%.

 

Manufacturing: In a several-step process, the iron is worked into sheets out of which discs are stamped. These are subsequently deep drawn.

 

Advantages:

  • Cost effective raw material and production
  • Great look, even if less modern and noble touch
  • Significantly more expensive than cast iron but still cheap in comparison to steel or copper

Disadvantage:

  • Thermal diffusivity is low. This results in heat spots during long warming-up period
  • Cast Iron skillets are very heavy
  • Prone to corrosion if kept wet or in humid conditions

 

Excursion: Comparing Cast Iron, Carbon Steel and Stainless Steel Frying Pans

On first sight you will have noticed the similarity between carbon steel and cast iron. Even though the materials are relatively similar in their properties, there are subtle differences. On foodal, you can find a very good comparison of iron vs carbon steel skillets. Here we try to summarize them on a practical comparison of carbon steel and cast fry pans.

We found this heat map comparison of a steel vs carbon steel and cast iron pan which perfectly demonstrates their difference in the ability to spread temperature.

 

 

Heat map of stainless steel, carbon steel and cast iron fry pan.

Heat map of stainless steel, carbon steel and cast iron fry pan. Source: @Kenjilopezalt

 

In the Olav lab, we have done more extensive testing of the world’s best cladded and disc-bottom cookware. Check out our results here.

 

Conclusion:

We have evaluated different materials according to preset criteria which we argue are the most important to consider for cookware.

 

Performance: check out our thermal comparison here.

 

Conductivity: Copper and aluminum are the materials that transfer and distribute heat significantly better than stainless steel, iron and carbon steel. In comparison to aluminum, copper conducts 20% better. In addition, copper has a very high heat capacity which gives the material more power while still being the most reactive to temperature changes. However, it comes at a higher weight.

 

Reactivity: Other than the less conductive materials, aluminum and copper are both food reactive which is why in everyday cookware they are covered by stainless steel in clad constructions or by a coating.

 

Capacity: Stainless steel, iron and carbon steel have high heat capacity at low conductivity. The cookware will stay hot for long and won’t cool out as fast as aluminum when adding large amount of refrigerated food.

 

Weight: Aluminum is very lightweight whereas al other materials are relatively heavy.

 

Maintenance & design: Carbon Steel and Iron require regular maintenance whereas stainless steel is probably the easiest to handle and (arguably) the most beautiful material.

 

 

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