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Common Materials of Cookware

by Michael Chu
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Over the last year, I've received several requests to write an article on cookware. This is a huge subject, and I've been struggling to figure out a way to present the information accurately and concisely. I decided to divide the information up into separate articles and focus this one on some common materials used in the construction of cookware. I also had to decide how much science and math to include. After some thought on the subject, since this site is called "Cooking For Engineers" and not "Cooking for Physicists", I've decided to include enough information that my readers will grasp the concepts without actually doing any derivations (perhaps this could be a future article). Also, since this article is a bit long and relatively complicated, if I've made any mistakes, please let me know so I can correct them as soon as possible.

The selection of pots and pans can be a complicated affair. The shape of the cooking surface and handle(s), materials used in its construction, the intended purpose of the utensil's design, and its flexibility of use in the kitchen all are important factors in choosing cookware. Understanding the materials used is a good first step in understanding how cookware works and what factors may be important to your cooking style.

Basic principles
The purpose of cookware is to impart energy to ingredients. In America, the energy comes mainly in two forms: burning natural gas or propane gas and electrical resistivity. In both methods, the source of the heat is not uniformly spread over the pan. In a gas stove, the gas come out at regular intervals and forms a ring of individual flames. The heating elements of an electric range are designed to cover as much area as possible, but still have patterns (usually spirals) where there is no heat. Because the heat is not applied evenly, the cook must be aware of this and either compensate with cooking technique or through cookware.

High quality cookware should not only be durable, but also take the energy from the heat source and effectively transmit this energy to the ingredients. There are several factors that affect this capability. The two most important factors are thermal conductivity and heat capacity. Almost all discussions concerning the materials used in cookware are focused on these two factors.

Thermal conductivity
In short, the thermal conductivity of a material is how readily that material absorbs and transmits (releases) energy. When the fire or heating element of a range comes in contact to a pan, the energy from the heat source is transmitted to the pan. This increases the internal kinetic energy of the pan (commonly called "heating up"). The heated material then transmits the energy to nearby materials that are at a lower average molecular kinetic energy level (at a lower temperature than the material). The higher the thermal conductivity of the material, the faster it will heat up and also, the faster the heated area will spread to unheated areas of the same piece of material.

For example, if we placed a large sheet of stainless steel (fairly low thermal conductivity as cooking materials go) on a burner and turned on the burner, the area directly under the burner would get hot while the rest of the sheet slowly heats up. The burner imparts heat quickly only to the region of steel directly over it. The rest of the pan heats up from the conduction of the heat from that spot. When the outer edges of the sheet have reached a hot temperature, the spot directly over the burner would be extremely hot. The figure below shows an example of the temperature of the sheet of steel over a gas burner. The hottest parts are shown in white, hot is red and cool is blue.


One solution to this problem is to make the sheet thicker. When heating a thick piece of steel (instead of a thin sheet), the bottom surface of the steel does not have the same temperature pattern as the top surface. Because the top surface is a greater distance from the heating element, the energy needs to conduct from the bottom to the top (just like the energy conducts outwards). The top surface of the steel is more evenly heated in this case. The figure below shows the thick sheet of steel after it has been sliced so the center of the front edge is where the burner heat touches the bottom of the sheet. The hot spot (white) is reduced by the time the heat conducts to the top surface of the sheet. Where the sheet is being heated, the temperature is more uniform now, but we still have uneven heating with this material.


For this reason, the thicker the steel, the less variation in temperature on the top surface. Unfortunately, low thermal conductivity means it a lot of energy needs to be imparted to the bottom of the steel in order to get the top hot. So a pan made of a low thermally conductive material will take a longer time to reach cooking temperatures. In fact, materials with low thermal conductivity take longer to react to any change in temperature, so the thermal response of the pan would also be slow. (Thermal response is how quickly the surface temperature of the pan reacts to when we increase or decrease the flame of the burner.)

In most cooking applications, it is desirable to have the utensil heat up quickly, not develop hot spots, and react to changes we make to the range controls. Materials with high thermal conductivity fulfill our needs because they transmit heat quickly resulting in fast response to thermal changes and even distribution of the internal kinetic energy.


Here is a list of some common materials used in cookware and their respective thermal conductivity:
MaterialThermal conductivity
Copper401 W/m*K
Aluminum237 W/m*K
Cast Iron80 W/m*K
Carbon steel51 W/m*K
Stainless steel16 W/m*K


Heat capacity
The amount of internal kinetic energy stored in a material can be referred to as it's heat capacity. This isn't the same thing as temperature, which is the average molecular kinetic energy within the material. For example, a kg of water at 100°F contains more energy than a kg of steel at 100°F. While thermal conductivity describes the materials ability to absorb energy, heat capacity is the amount of energy that is needed to raise or lower the temperature of the material. The molecular composition of some materials is such that as they absorb energy, much of it gets converted into potential energy and only a small amount increases the molecular kinetic energy (water is a common example). Other materials, like most metals, increase their molecular kinetic energy readily and do not store much of the absorbed energy as potential energy. The heat capacity of a material is proportional to its mass. So, a 2 kg piece of steel has double the heat capacity of a 1 kg piece of steel (make sense, right?).

What this means is that cookware made of materials with high heat capacity, will take longer to heat up, but will also have a significant amount of energy stored up when it is hot. When energy is pulled out of the material, the temperature of the material will lower slowly when compared to materials with low heat capacity. Cast iron is often cited as an example of a high heat capacity cookware material. The specific heat (the heat capacity of a material for a given mass) of cast iron is half of aluminum's specific heat, but because cast iron cookware is generally several times the mass of aluminum cookware, it has a much higher heat capacity.

The thickness of metals used in the construction of cookware are often sited by the manufacturer (for example, 3 mm aluminum), but since heat capacity is a function of the mass of the material, density must be known to make comparisons between cookware of different materials.
MaterialSpecific HeatDensity
Aluminum910 J/kg*K2600 kg/m3
Stainless Steel500 J/kg*K7500 - 8000 kg/m3
Carbon Steel500 J/kg*K7500 - 8000 kg/m3
Cast Iron460 J/kg*K7900 kg/m3
Copper390 J/kg*K8900 kg/m3


Looking at the table above, if you multiply specific heat with density, you'll find that the heat capacity per unit volume of steel, cast iron, and copper are about 1.5 times that of aluminum. This means, to achieve the same heat capacity in an aluminum pan as in stainless steel pan, the aluminum pan needs to be 1.5 times as thick (assuming the other pan dimensions are the same).

Pulling it together: thermal diffusivity
If you've been paying attention, you'll realize that I've misled you when I discussed thermal conductivity. Thermal conductivity alone does not determine how fast the pan will heat up (and also how evenly it will heat). In fact, the heat capacity plays a role in determining this as well. Wouldn't it be great if we had a single number that told us at what rate heat would transfer through and spread out in the material? There is, it's called the thermal diffusivity of a material and is simply the thermal conductivity divided by the unit heat capacity (specific heat times density). Let's take a look at how the materials stack up:
MaterialThermal diffusivity
Copper120 * 10-6 m2/s
Aluminum100 * 10-6 m2/s
Cast Iron22 * 10-6 m2/s
Carbon Steel14 * 10-6 m2/s
Stainless Steel4.3 * 10-6 m2/s

Without additional calculations based on the heat conduction equation, there is very little that we can do with this table of values, except compare the materials against each other. It is clear, however, that the best performing materials (in terms of both holding and dishing out energy) are copper and aluminum. This leads us to our final consideration: reactivity.

Reactivity
Not only do we have to concern ourselves with the thermal properties of materials, but we need to make sure that the materials we use in our cookware do not harm us or adversely affect the taste of our food (you decide which is worse). For this reason, in addition to the high thermal diffusivity, we would also like a non-reactive material. Unfortunately, both copper and aluminum react readily to foods. (Copper, when ingested in quantity or consistently, can cause liver, stomach, and kidney problems as well as anemia. Also, aluminum has long been suspected of contributing to Alzheimer's disease. Oh, every cookbook mentions, at this point in the discussion, that the occasional foamed egg white whipped in a copper bowl is not enough to harm you - but refrain from cooking every day on exposed copper.) Stainless steel, the least reactive of all popular materials used in cookware, also has the worst thermal diffusivity.

It seems that today, physics is not our friend. But, through the magic of cookware companies wanting to find ways to charge us lots of money, solutions have been devised to enable us to enjoy cookware made of materials with high thermal diffusivity and low reactivity. By combining the non-reactive surface of stainless steel with the thermal properties of copper or aluminum, you get the best of both worlds. There are several variations on this theme: steel- or tin-lined copper, stainless steel with aluminum or copper disk, stainless steel cladded aluminum, and stainless steel cladded copper. The table below summarizes my subjective assessment of the effectiveness of various material combinations (they are listed in order from most effective to least):
RankCompositionComments
1Copper with tin liningHighest response; tin lining can be finicky can be susceptible to melting; copper exterior requires more care
2Copper with stainless steel liningCopper exterior requires more care but imparts the utensil with copper's excellent thermal properties
3Aluminum with stainless steel liningThick aluminum provides excellent thermal response to thin steel interior
4Copper fully clad by stainless steelCopper layer may be thinner than copper with stainless steel lining; exterior and interior are durable and easy to maintain
Aluminum fully clad by stainless steelAluminum layer may be thinner than aluminum with stainless steel lining; exterior and interior are durable and easy to maintain
Aluminum with stainless steel lining and copper exteriorSame performance as cladded aluminum, but with the difficulties in maintaining copper
5Stainless steel with copper diskCurved edge of the bottom causes the disk to not come into full contact with the complete bottom of the pan resulting in inferior heat conduction as compared to cladded copper
Stainless steel with aluminum diskSame as stainless steel with copper disk


Previously, I mentioned that cast iron has a large heat capacity as compared to the other materials (mostly because of the mass used when making the cookware). Because of this attribute, cast iron gets a special place in the kitchen. When the cooking task requires the ability to maintain consistent heat (and ample amounts of it), nothing beats cast iron. Because cast iron can react with acidic foods and ingredients that are cooked for a long time, cast iron cookware is seasoned - a process by which layers of fat are slowly cooked into the porous iron until the fat polymerizes forming a protective barrier (and makes the utensil relatively non-stick).

Common materials and how they compare
Now that we've looked at the important properties in selecting cookware material, let's take a look at each of the common materials used in cookware.

Copper
DescriptionCopper is a soft (scratches easily) but durable (will last a lifetime) material that has great thermal properties. The material is prone to oxidation but with care, will retain its beauty indefinitely.
Pros
  • High thermal diffusivity
  • With enough thickness, pans heat extremely evenly
  • Extremely responsive
Cons
  • Heavy
  • Extremely expensive
  • Copper surface can tarnish or scratch
  • Pan may cool too fast after removal from heat (due to extremely high thermal conductivity)
  • Cooking directly on copper may result in undesirable levels of copper intake
Best uses
  • When lined with tin, nickel, or stainless steel, excellent for all stovetop uses.
Care
  • Hand wash with a non-abrasive detergent and hand dry
  • Regularly use polish on exposed copper to preserve shine
Examples

Aluminum
DescriptionPlain aluminum utensils are low-cost, light-weight, and thermally responsive - but it's reactive. Teflon coated aluminum utensils are low-cost and both non-stick & non-reactive. Anondized aluminum has been treated to develop an aluminum oxide (extremely hard and non-reactive) coating on the surface of the utensil. Clad or lined aluminum has had stainless steel bonded to the interior of the utensil to form a non-reactive surface.
Pros
  • Extremely low cost if plain or teflon lined; moderated priced when anondized
  • Great thermal properties
Cons
  • Very expensive if stainless steel lined or clad
  • highly reactive to acid ingredients (and somewhat reactive to alkaline as well)
  • Lower density may require thicker construction to increase heat capacity
  • Unless anondized or lined or clad with stainless steel, may warp under high heat
  • Unless anondized or clad, aluminum is prone to scratching.
Best uses
  • Plain aluminum - good for non-acid foods, like boiling stock or cooking pasta
  • Coated aluminum - excellent for all purposes if aluminum is fairly thick
CareHand-wash with a mild detergent and washcloth or sponge.
Examples

Cast iron
DescriptionCast iron is composed on iron, carbon (more than carbon steel), and trace elements found in common clays. The iron is melted down and poured into a sand or clay mold to form the utensil. Enameled cast iron has a thin but durable nonreactive layer of glass fused to the surface of the utensil.
Pros
  • Plain cast iron is low cost
  • Manufacturing process results in thick and dense cookware for unparalleled heat capacity
  • Thickness also results in even heating
Cons
  • Enameled cast iron can be expensive (although some are moderately priced)
  • High heat capacity means the utensil takes longer to heat up
  • Although extremely hard, can crack or fracture if dropped or thermally shocked (pouring cold water into a hot pot)
Best uses
  • Traditional woks (plain cast iron), skillets, Dutch ovens
  • Southern cooking
CarePlain cast iron should be seasoned before first use and as needed. A seasoned utensil should receive minimal contact to soap or detergent. Wash by soaking in warm water for a few minutes and repeatedly scrubbing with salt and rinsing until salt remains white (usually one scrubbing is does it). Dry with a cloth and heat over low heat briefly to evaporate all moisture. For enameled cast iron, hand wash in hot soapy water.
Examples
  • Lodge Logic (low cost cast iron)
  • Wok Shop (low cost cast iron traditional Cantonese wok; this wok is awesome, but its rounded bottom works best on gas stoves)
  • Le Creuset (expensive enameled cast iron)

Carbon steel
DescriptionCarbon steel contains less carbon than cast iron and is formed and pressed from sheets instead of being casted. It can be annealed (heating the metal until its molecular structure realigns to alleviate internal stresses and then specially cooled to preserve the new structure) to form blue steel (or black steel), a harder and less reactive material. Carbon steel can also be enamel coated.
Pros
  • All variations are usually low cost
  • Fast seasoning process for carbon steel; enameled carbon steel and blue or black steel does not need seasoning
Cons
  • Poor thermal properties means slow heat up and uneven temperatures.
  • Thin and light (this might be a pro for some people) which results in very little heat capacity
Best uses
  • Fry pans, saute pans, woks
CareShould be seasoned before first use. Care for as if it was cast iron. If desired, pan can be washed in soapy water, scoured, and reseasoned quickly (15 minute seasoning) because of its less porous nature than cast iron.
Examples

Stainless steel
DescriptionMixing steel with chromium and nickel (18/8 stainless steel is 18% chromium and 8% nickel while 18/10 has 10% nickel) produces a corrosion resistance steel that is both hard and easy to maintain a shine. Disks of copper or aluminum can be fused to the stainless steel cookware to enhance its thermal properties. Stainless steel can also be used to line copper or aluminum utensils as well as cladding aluminum or copper (see aluminum and copper cookware summaries above).
Pros
  • Plain stainless steel and stainless steel with aluminum or copper disks are low cost to moderately priced
  • Shiny surface makes it easy to see how your food is browning
  • Corrosion resistant and easy to clean
  • With a thick aluminum or copper disk or clad around a core, stainless steel becomes one of the best materials to cook in (not just for its thermal properties, but as well as durability, ease of care, and visual control of cooking - all the benefits of stainless steel with very little of its drawbacks)
Cons
  • Plain stainless steel: worst material to cook on (in terms of thermal properties)
  • Salt may cause pitting over time unless added to boiling liquid
Best uses
  • Plain stainless steel: boiling water (steaming is okay) and non-cooking related tasks (mixing bowls, storage containers, etc.)
  • Stainless steel with copper or aluminum disk: great for all purposes if disk is well bonded and of a fair thickness
CareHand wash with mild detergent. Use gentle abrasives as needed.
Examples

My personal favorites for cookware materials are stainless steel clad aluminum or copper and cast iron (for skillets and woks). The stainless steel clad utensils perform well, are easy to clean, and look beautiful. Of course, not all stainless steel clad aluminum (sometimes called tri-ply or five-ply depending on construction) are the same. All-Clad has definitely earned their reputation as quite possibly the best general use cookware money can buy, but it's a lot of money to be spending. All-Clad rarely goes on sale, but other reputable brands, such as Calphalon, have clad lines as well - and they are more likely to have their product lines go on sale. Keep checking the Cooking For Engineers Deals Blog to see when deals do come up.

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Written by Michael Chu
Published on July 15, 2005 at 12:22 PM
95 comments on Common Materials of Cookware:(Post a comment)

On July 16, 2005 at 11:36 AM, Matt (guest) said...
Hi Michael,

Excellent post. I've been wondering recently whether to upgrade my cookware... and to what. I'm using a Viking saute pan at the moment, which i believe is very thick stainless steel with an aluminium base... but i find it takes so long to heat up that i often prefer cooking with my cheap K-mart brand frying pan...

After reading your post, it's confirmed a number of thought's i've had... in regards to heat transfer and capacity. I'm thinking a nice Mauviel saute pan would look great on my stove top.

Cheers :)
Matt


On July 16, 2005 at 12:01 PM, eesh said...
Subject: Teflon
Hi Michael,

I was hoping to see something about Teflon (Or any kind of non-stick coating), as well.. How it works, care it requires, etc. Will you write something about it in the future?


On July 16, 2005 at 01:37 PM, an anonymous reader said...
Farberware used to make aluminum-clad stainless steel cookware which had a a much thicker aluminum layer than the products they are now producing.

If you live in a metropolitan area you can often find them at garage sales -- and at 50 cents to a couple bucks per pan, this excellent cookware is a steal.

Often you can find the older stuff on eBay, as well. I recently puchased a huge skilllet, with lid, of this vintage Farberware for about 15.00.


On July 16, 2005 at 06:58 PM, Michael Chu said...
Subject: Re: Teflon
eesh wrote:
I was hoping to see something about Teflon (Or any kind of non-stick coating), as well.. How it works, care it requires, etc. Will you write something about it in the future?

In the future, I will have a (shorter) discussion on non-stick cookware. My current problem is that I can't seem to get enough info on the newer non-stick solutions (Scanpan, etc.) and I'd like to include those as well.


On July 16, 2005 at 08:23 PM, Adam Fields (guest) said...
Subject: cybernox
Definitely include cybernox in that list, if you can get any info about it.

I have a few cybernox pans, and they're great, but I have no idea what they actually are.


On July 17, 2005 at 05:00 AM, Ned Konz (guest) said...
Subject: Aluminum probably not suspect in Alzheimer's disease...
At least according to the Alzheimer's disease association, there doesn't seem to be a convincing link between aluminum and Alzheimer's disease.

Of course, I don't really like the taste of aluminum in my foods...

However, many of the non-stick coatings outgas irritating or toxic gases when heated strongly (which those of us who stir-fry a lot tend to do). These gases can sicken people and kill birds.


On July 18, 2005 at 05:03 PM, Streever (guest) said...
Subject: Teflon
Teflon certainly isn't a good material to cook on...you lose so many wonderful cooking techniques (such as deglazing...) & the health risks are many.

Teflon is a persistent chemical.


On July 18, 2005 at 07:18 PM, mole6e23 said...
Subject: Stainless clad cast iron
You didn't seem to mention stainless clad cast iron (unless I missed it). My mom has a set that she bought in roughly 1965 that are some of my favorite pans to cook with (she bought a 7 pan set from a door-to-door salesman for $300 which was close to their monthly income at the time!) Except for some problems with the handles, the pans still look almost new even though they've been through three children and numerous dishwasher cycles.

Are these types of pans still available?


On July 19, 2005 at 01:05 PM, Ht354 (guest) said...
Subject: Cookware Purchasing
I read the review with great interest. Although the research is reflective of the results found elsewhere, ie Consumer Reports/Cook's Illustrated, what is left out is the all important human factor.

How does the cookware feel when you handle it? Does the handle get Hot? Will it take hours a week to keep clean/looking nice? The easiest way to answer the question is to recommend any verison of the "All Clad" cooking tools. They come in both regular and nonestick, handles stay cool, they are comfortable, conduct heat well and evenly considering the Stainless Steel quotient, and will be the last set of pots & Pans you'll ever buy. Oh yea, "all Clad" is always rated in the top two by Consumer Reports/Cook's Illustrated etc., not to mention most major cooks without a cookware deal use it also, just watch the food network/TV.

Don't get me wrong, you can go with Faberware, and TFal and so on and so on, but you'll replace it every 5 to 7 years, and eventually pay more in a lifetime than if you bought "All Clad" up front.


On July 19, 2005 at 01:38 PM, Shalmanese said...
Subject: Egullet link
Hi,

Check out the egullet understanding stovetop cookware for another excellent take on this topic.


On July 19, 2005 at 05:46 PM, John Elledge (guest) said...
Subject: Cookware
No cookware does everything well. My opinion is that each piece should be selected for a specific technique. For example stainless with a thick disk bottom is good for sauce pans but poor for an omelet pan for the same reason: the sides don't get hot. Aluminum or copper stainless ply makes for a great skillet but would tend to radiate heat out the sides if used for a saucepan. I have some All-Clad stainless and like it's cooking performance but dislike the riveted handles (the rivets on the inside of the pan are difficult to clean) and the polished stainless exterior looks good when new but scratches if you use a Scotchbrite pad on it. I am now using Demeyere Apollo (stainless steel) sauce and saute pans and like the Silvinox finish and the welded handles. They do look a bit industrial though! I enjoyed the article, thanks for writing it.


On July 20, 2005 at 02:49 PM, RJ Keefe (guest) said...
Subject: All-Clad
All-Clad cookware may be expensive, but to all appearances it's eternal. I expect that people will be inheriting the stuff pretty soon, and I wonder what All-Clad plans to do about this, business-model-wise.


On July 20, 2005 at 09:45 PM, dakirw (guest) said...
Subject: Cookware Safety Links
Some cookware safety links:

Cookware Safety
FDA article

Might be a bit out of date, but still handy


On July 22, 2005 at 06:03 AM, mmcneill said...
The cookware I use most often is a 5 by 7 by 1.25
inch casserole pan from Nordic Ware. It has
badly applied non stick that I am pleased to see
is rapidly flaking off. It is steel so will
work on my induction cook top. The greatest
use is for baking between the smooth hot
upper and lower plates of my Griddler panini griddle.
It makes beautiful casseroles, bakes a roast, or heats frozen entres.
If I need a lid
another pan inverted and held on by two
one inch paper clamps that squeeze easily around
the two rims.
It has many uses except for microwaving.


On July 26, 2005 at 03:50 AM, Quelyn (guest) said...
Subject: Forgot a type of cookware
Enamel clad Aluminium You might be more familiar with one of the better brands called Graniteware. Usually dark blue with greyish flecks.

This type of cookware is thin aluminium coated with enamel inside and out. Used by our Grandmothers when cooking and still around. Relatively cheap. Usually found in camping stores or where you find home canning supplies for the larger pots.

Excellent if you want to boil anything. Horrible if you want to cook something slowly.


On July 26, 2005 at 09:06 AM, Cathy Tallmadge (guest) said...
Subject: Cookware
Some of the best cookware is availible at restaurant supply stores. I discovered a line that is like All Clad but at about half the price called Tribute, made by the Vollrath company. These stores also have the best non stick fry pans for eggs, omelets, frettattas etc. I recommend the Lincoln Wearever Ceramigard line for this type of cooking. There is no set of cookware that does everything. I use cast iron, enamel clad cast iron and even glass, depending on what I'm doing. Cookware doesn't have to match, it has to work. As for enamel clad aluminum cookware, it's good for one thing..... nothing. O.K. maybe boiling water.


On August 21, 2005 at 08:48 PM, connordr (guest) said...
Subject: Non-metallic cookware
You do not include Corningware or pyrex in your survey. I do use a Corning glass double boiler and also use itin the microwave. THe poor conductivity of glass makes it unacceptable for most other uses. I have not tried Corningware -pyroceramic- recently, but as I recall it had much the same problem. In general I find glass -pyrex- ideal for baking with the exception of slow cooked beans which do best in earthenware.
Will there be another article on what works best in an oven?


On August 22, 2005 at 03:50 AM, Chef Jim said...
As has been mentioned there's no set that will satisfy all needs. I use All-clad as my primary set, love it, does excellent job, great quality. I have a set of non-stick Calphalon that I am very disappointed with seems to wear out almost as quickly as T-fal, wearever, etc. but was far more costly. But now I'm limiting it's use to eggs and fish so no problem! I also have two non-stick Revereware sauce pans, they have pouring spouts and glass lids with strainers. These do come in handy, great for heating leftovers, sauces, etc. Also have two castiron pieces a 12in frypan and a two-burner grill/griddle. Next purchase will be Enamel over castiron dutch oven. 16Qt Stock pot is All-Clad but only the bottom is three-ply which is fine for simmering stock and Pasta Pot is inexpensive S/S with glass lid. Wore out one that I loved it had s/s lid with two vents and could cook pot of pasta with lid on and no boil overs! This glass lid only has one vent and it has to be watched for boilovers constantly, on the good side it is glass so you can anticipate better!


On August 29, 2005 at 03:19 PM, Mark Leng (guest) said...
Subject: No need for non-stick coating
Despite my wife's insistence, I had a hard time believing stainless steel would be almost as easy to clean as non-stick coated pans. I'm happy to say our All-Clad is very easy to clean, especially if you don't let the food dry on it overnight. ;-)

The worst cases have required some soaking with water and dish detergent but that's it. And there's no seasoning required, unlike cast iron.

The only thing that really stuck to the All-Clad was a melted $3 plastic steam basket. (don't ask)

Freezing, WD-40, Simple Green and Wright's Silver Cream cleaned the pan up nicely. My only hope is that I didn't damage the corrosion resistance of the stainless steel.

Does anyone know if I could have permanently damaged the stainless steel somehow?


On August 30, 2005 at 03:51 AM, jimjimjim9 said...
Stainless is an alloy from which the pan is made, not a coating ( ie teflon or anodized aluminum.

Here's a fun place to start inquiy into stainless:

http://www.corrosion-doctors.org/MatSelect/corrstainsteel.htm


On August 30, 2005 at 03:04 PM, an anonymous reader said...
Thanks Jim.

I had read about the chromium-oxide "layer" on stainless steel (see below) and wondered if I had damaged the corrosion resistance of the All-Clad, or any of its inherent non-stick properties.

I'm really out of my element here so my questions might seem a bit "daft." ;)

Is the chromium-oxide layer important for cookware? If so, does it require maintenance or special care?

Thanks.

"Stainless steel can corrode in service if there is contamination of the surface. Both pickling and passivation are chemical treatments applied to the surface of stainless steel to remove contaminants and assist the formation of a continuous chromium-oxide, passive film."

"The purpose of passivation of the surface is not only to clean and remove free iron, but to maximize the chromium content of that top, very thin "layer" of chromium oxide. (Other metals in the alloy also greatly affect this.) This gives the best corrosion resistance,"

"As you are no doubt aware, one of the attributes of stainless steel is the fact it has a built in oxide layer over it. This is in the form of chromium oxide and it is this that gives it its corrosion resistance. If you want to enhance this, you have to be careful how you do it; if you simply anodically polarise it, you will run the risk of breaking down the existing layer and dissolving out the metals. You could try putting it in hydrogen peroxide and leaving it, or better still, try electropolishing it."


On October 07, 2005 at 02:25 PM, geo said...
I am new to this forum but have been reading the excellent articles on cookware materials! Thank you! I have been ruminating for the past week almost all of my day! :shock: over which cookware set to purchase and hope someone can offer advice. I have a cast iron 5 qt dutch oven and cast iron frying pan. I am not a pro but just very interested in cooking/baking with high quality pans at a reasonable price. I read about some test that put tied for 1st place Tramolina and Cuisinart cookware. I have no other info on who did the test (read about it at Chef's Depot but no detail) I have seen at Burdines a Chef's Classic set by Cuisinart and there is a Cuisinart Multiclad which is what I was interested in and (I think) is their professional line. It has the aluminum going up the sides, too. The problem is, I have no idea how to find out the THICKNESS of the ALUMINUM. I don't know what else to do. Sale ends VERY soon on this 12 pc CUISINART MULTICLAD set which has ALL the pieces I need for $210. Any suggestions? Could the thickness of the aluminum be published anywhere or can anyone point me to any tests/awards? Supposedly, the Cuisinart line is endorsed by French chef (I think his name is) Paul Bocuse. He endorses the Chef's Classic line which has the aluminum disc only (not up the sides). I know endorsements often don't mean a thing. I am so confused. Any thoughts or advice would be appreciated.

geo


On October 07, 2005 at 04:54 PM, Guest (guest) said...
Subject: Teflon?
Nice, thorough discussion. There is more to cookware, of course, than the material, as other posters have noted.

Regarding the possible health risks of using teflon, there are none.

http://www.cei.org/gencon/019,04820.cfm

It is true that there may be some health risks caused by a chemical used to <b>make</B> teflon (namely perfluorooctanoic acid, or PFOA), but that is a problem for chemical factory workers and perhaps people who live near the factories, not people who use teflon. There is no PFOA in actual teflon.

http://www.planetark.com/dailynewsstory.cfm/newsid/29003/story.htm

Teflon itself is chemically unreactive; in fact, it is one of the least reactive substances ever discovered. If we ate some teflon, it would pass through our bodies unchanged. None of it would enter our blood stream. But even if it did, it would would not affect any of our biochemical processes, since it is unreactive. It would interact with the body about as much as a stone reacts to me shouting at it. In fact, that unreactivity is part of why it is so slippery. Maybe the subject of another article in Cooking for Engineers?

People pay lots of attention to health scares, as they should, but they often don't take time to look at it carefully. PFOA is not an "ingredient" of teflon, it is one of the chemical precursors of teflon, like oil is to polyurethane. If oil is bad for you, it doesn't mean that polyurethane is. (And in fact, high-density polyurethane is totally inert in the body just like teflon, so it is used in artificial joints and the like.)

Like EMF radiation from powerlines, this one appears to have been cooked up by trial attorneys looking to make a buck.

Karl


On October 26, 2005 at 08:10 PM, Misc (guest) said...
Subject: DDTs were great too.....
"Frying pan fumes kill canaries"
http://news.bbc.co.uk/2/hi/science/nature/3441255.stm

Admittedly, canaries are not humans, but Teflon seems to break down under high temperatures according to one group of researchers (absolutely not! says the other side - Teflon is unreactive).

It's always like this - everyone argues and there are strong motives for lying and exaggeration - but at the end of the day we're built out of the same basic stuff as canaries so I think I will give Teflon a miss - if it's killing them then it's most likely partially killing me...

(from the viewpoint of an economist in his 20s) < always important for evaluating info i.m.o - how much do they really know about x, y or z after all... perhaps not too much in my case, but I do like to think critically - I dislike selective evidence - now you have both sides to consider. ^.^

[edit] from that link posted earlier:

Although nonstick pans will wear away with hard use and particles may chip off, the Food and Drug Administration has stated that these particles would pass unchanged through your body and pose no health hazard. A coated pan heated for long periods at high temperatures will give off fumes, but these are less toxic than fumes given off by ordinary cooking oils.

Do these people ordinarily cook with crude oil or something!??!


On October 30, 2005 at 11:17 PM, Ted N. (guest) said...
Subject: Great stuff and solid advise
The info you tell reflects the experiences I have with cookware. it is accurate and on target in my opinion. I spent 20 years cooking and 5 selling cookware. all clad is good stuff but priced high, there is tri ply from cuisinart and calphalon at a lower cost. viking is great and more ample in space but way up in price. my personal favorite is the Gourmet standard tri ply, it has the best comfort with solid performance. I love the handle and the solid construction. I am not afraid of teflon but keep the heat down its not my choice for searing or high temps best for eggs and pasta. I protect the pan surface with the panjacket cover to store all my cookware that way. keep up the great info. Ted :)


On November 06, 2005 at 09:33 AM, dg (guest) said...
Subject: Cast Iron
After years of trying various combinations of expensive and more expensive aluminum, teflon coated aluminum, anodized aluminum, stainless clad aluminum etc we have gone back to cast iron for most uses except boiling. Cheap, easy to clean, bombproof, nonstick, even heating, and can be made really really hot for searing without worry. Heavy, so we just leave it on the stove.

Runner up is stainless clad aluminum, but it is harder to clean and not as nonstick, and much more expensive.


On November 29, 2005 at 10:08 PM, tg4360 said...
Subject: Tri-ply = good stuff
Thanks for the great information source.

To add a data point:

After much research and reading here and else where, I picked up the member's mark tri-ply cookware at Sam's club. I could never afford an All-clad set right off so this get's me the same performance at a great price. So far the quality and performance is right up there with All-Clad. I know I'll probably pop for something from the big "A" just for the fun of it but I'm very happy with my selection.

Reading about material and construction/performance here was a great help in my selection.

THanks!


On November 30, 2005 at 03:55 AM, hubiquitous (guest) said...
Subject: Induction cooktop vs Copper/Aluminum cookware
Thanks for the straight-up science. Bring on the physics!

I am very close to picking up a set of Copper-clad cookware from All-clad. It is copper-lined w/ stainless steel coating so it should have the best of both worlds- good heat properties and low reactivity with food. But, it will not work as good with an induction cooktop as good, old-fashioned steel or cast-iron.

There are several things I like about induction cooktops (stays cool to touch), but the biggest is it's rated efficiency. Can anyone compare the efficiency of an induction cooktop to a high-end ceramic cooktop? What about the heat properties of a good stainless steel set on an induction stove to a aluminum/copper clad set on a decent stove?

~Thanks


On December 08, 2005 at 03:11 PM, an anonymous reader said...
Subject: Stainless Steel and Chromium Oxide
For the poster who asked about maintaining the oxide layer on stainless steel, from a consulting metallurgist:

The oxide layer on stainless steels is (a) self-maintaining, and (b) very diffficult to remove. Unless you're performing electrochemical experiments in your cookware, or cooking with concentrated acids, you won't damage the stainless. If you are doing those things, the condition of your cookware is probably not your biggest problem.


On December 12, 2005 at 07:55 AM, largejunglecat (guest) said...
Subject: Stainless steel, oxide layer
The chromium-oxide layer on stainless steel is the result of oxygen in the air reacting with the chrome in the stainless steel alloy. Even if you did manage to remove it, the reaction is pretty fast (If you've ever welded on stainless steel you know how quickly the oxide layer returns), especially when the steel is heated, which is a regular occurence for a pot or a pan. Because this layer is pretty non-reactive, it actually serves to protect steel.

What makes stainless steel so much nicer than regular steels is that chromium oxide is not air-permeable, so only a very thin layer at the surface reacts. Iron-oxide, which developed when normal steel reacts in air, is much less attractive and is air permeable. As a result, a piece of mild steel can corrode all the way through.


On December 13, 2005 at 12:26 AM, largejunglecat (guest) said...
Subject: radiative heat transfer vs. looks/conductivity
Since this is cooking for engineers...

I was wondering a while back, while thinking of excuses not to clean the copper bottom of my cheap stainless steel pan, whether the better radiative heat transfer that I'm bound to get from the non-shiny, more darkly colored surface of my discolored copper is worth decrease in conductivity that I assume I will get due to the oxide layer that is causing the discoloration.

Obviosly this is assuming that I'm not concerned with the asthetic aspects of the pan, since shiny things are definitely prettier.

Anybody happen to know?


On December 14, 2005 at 03:45 PM, an anonymous reader said...
I have to say that I really enjoy cooking on my Calphalon commercial annodized alluminum pans. I got them for a real steal (90% off), but watch out for pans made in china rather than Toledo, OH. I've never used All-Clad as the price was prohibitive, and with a lifetime warranty on my Calphalon, I'll never need to.

As far as the Alzheimers thing goes. Studies have shown that the original premise was false. Doctors had been finding elevated levels of aluminum in the brains of Alzheimers patients so they naturally linked it to the disease. Now though, studies are showing that the Alzheimers may cause the elevated aluminum levels rather than the other way around, and that aluminum causes no harm to the body.


On December 19, 2005 at 05:14 PM, ken mines (guest) said...
Subject: problems with non-stick pans and induction hob
recently installed a Neff induction cooker and hob. New stainless steel pans work well, but two non-stick frying pans take for ever to heat up - in fact the smaller pan which we bought for omelette cooking is useless for this - as well as long time to heat it never gets to a high enough heat to cook quickly, as an omelette should. Has anyone else had problems with non-stick and induction (the pans are magnetic and are being sold for induction use)


On December 26, 2005 at 07:24 PM, Mike (guest) said...
Subject: aluminum and disease - rubbish
Most antacides are compunds of aluminum (eg. aluminum hydroxide). These have been sold for a long time - they're a standard therapy for heartburn, no-body considers them dangersous, and the amount of aluminum you actually swallow with antacids (excluding the calcium ones, like Tums) is at least 2 orders of magnitude greater than ANYTHING you'd ever get from cooking in an aluminum pot - like ten years exposure per teaspoon. So, if aluminum predisposed to alzheimers, people who take antacids would all be brain dead. Aluminum is HARMLESS.


On January 02, 2006 at 04:03 AM, Joe (guest) said...
Subject: yummy nonstick coating and working with bad cooktops
I was worried about this for a while when my mom continued to use a pan which was peeling. I did some research and found out dupont got teflon classified as a food additive. Though I personally stay a way from nonstick it isn't for any safety reasons.

Also, I have a horrible cook top in my apartment and often find myself doing dishes requiring searing. I can get around this using cast iron which holds enough heat that I can finish searing before the thing noticeably cools down.


On January 15, 2006 at 10:53 AM, TruthFinder (guest) said...
Subject: Aluminum Toxicity
Aluminum toxicity is a recognized medical condition.

http://www.healthy.net/asp/templates/article.asp?pagetype=article&id=1958

With use of aluminum pots and pans and aluminum foil, some aluminum leaches into food, especially with acid foods such as tomatoes or rhubarb. Cooking with fluoridated water in aluminum cookware increases the aluminum in the water and the food; still, the amounts we obtain in this manner are small in comparison with those from additives. Aluminum salts used in antiperspirants are not a major contaminant either, unless these products are overused. (Aerosol sprays, however, should be avoided for environmental toxicity reasons.) Antacids containing aluminum hydroxide can be a big source if they are taken regularly or abused, as antacids sometimes are. Some children's aspirins have been found to contain aluminum as well.

http://www.doctoryourself.com/alzheimer.html

A single aluminum coffee-pot was shown to have invisibly added over 1600 mcg aluminum per liter of water. This is 3,200% over the World Health Organizations set goal of 50 mcg per liter. Aluminum is known to build up in the bodily tissues of persons with Alzheimers disease, Parkinsons disease, and amyotrophic lateral sclerosis. Aluminum is a known neurotoxin. Aluminum is also a component of so- called silver amalgam dental fillings. Composite (white) fillings do not contain aluminum (or mercury, for that matter.) Most baking powder contains aluminum. Rumford brand baking powder does not, however. Neither does baking soda, which is a different substance entirely.

FACT: More than half of nursing home beds are occupied by AD [Alzheimers Disease] patients.

FACT: Alzheimers disease is the Number 4 Killer of Americans, causing over 100,000 deaths each year in the USA alone.


On January 15, 2006 at 11:04 AM, TruthFinder (guest) said...
Subject: Teflon Toxicity
http://www.ecomall.com/greenshopping/teflon4.htm

In new tests conducted by a university food safety professor, a generic non-stick frying pan preheated on a conventional, electric stovetop burner reached 736°F in three minutes and 20 seconds, with temperatures still rising when the tests were terminated. A Teflon pan reached 721°F in just five minutes under the same test conditions (See Figure 1), as measured by a commercially available infrared thermometer. DuPont studies show that the Teflon offgases toxic particulates at 446°F. At 680°F Teflon pans release at least six toxic gases, including two carcinogens, two global pollutants, and MFA, a chemical lethal to humans at low doses. At temperatures that DuPont scientists claim are reached on stovetop drip pans (1000°F), non-stick coatings break down to a chemical warfare agent known as PFIB, and a chemical analog of the WWII nerve gas phosgene.

http://ww3.komotv.com/Global/story.asp?S=3615478

A $5 billion class-action lawsuit is being filed against DuPont for failing to warn consumers of the dangers of an ingredient allegedly contained in Teflon, lawyers said Tuesday.

Two Florida law firms told the Associated Press they were filing the federal suit on behalf of 14 people in eight states who bought cookware coated with non-stick Teflon. It reportedly is made with a chemical called perfluorooctanoic acid (PFOA), which earlier this month the U.S. Environmental Protection agency said is "likely" to cause cancer in people, the AP said.

The plaintiffs contend DuPont has known for more than 20 years that the product caused cancer in lab animals, according to the AP. A company spokesman said federal t