Make It Monday: Cookware 101 - Different Construction Types
Cookware is the lifeblood of your kitchen, but the large number of options can be confusing. Stainless steel, carbon steel, cast iron, non-stick - what are the differences between these choices? In today's post I will break down the basic construction of cookware and lay out some advantages & disadvantages of each.
Job 1: Heat Transfer
The number one job of your cookware is to transfer the heat from your stove to the food you are cooking. Different materials do this better than others. The scientific property that measures the ability to transfer heat is call thermal conductivity. This is an attribute that can be measured, and thus ranked. The rank for common cookware materials by thermal conductivity, from best to worst is:
- Copper - 390
- Aluminum - 160
- Cast Iron & Carbon Steel - 50
- Stainless Steel - 16
- Stoneware - 2.5
- Glassware - 2.5
As you can see, there is a wide range in these materials. Copper is the best at distributing heat, and the 2nd best, Aluminum, is half as effective as Copper. And Stainless Steel is barely better than Stoneware.
Depending on what type of cooking you are doing, the thermal conductivity of Cast Iron or Carbon Steel would be fine. But for certain types of cooking where very exacting control of temperature is important (e.g. sauces), the Copper or Aluminum would be preferred.
Hot Spots or Not
A second property of cookware is to distribute the heat it is conducting across the cooking surface. When heat is distributed evenly the entire cooking surface is fairly uniform in temperature. When the heat is distributed poorly you will have hot spots and cool spots across your cooking surface. Again, this matters more in certain cooking instances than others - but it is good to know when you go to grab a pan.
Sometimes the best reaction is No Reaction
Ideally, you want your pan to be non-reactive. A non-reactive pan is one that will not impart any tastes into the food being cooked. Most pots an pans are non-reactive for most cooking chores. The one exception is Cast Iron, which may impart a metallic taste into acidic foods (e.g. tomato sauce).
He ain't heavy, he's my fry pan
Weight is another important characteristic to consider. While a big and heavy cast iron dutch oven will be perfect for a low and slow stew, you want a fry pan that is light enough for you to move it around on the burner with ease.
OK. Now that we have gotten a few of the basics out of the way, let's look at some of the popular options available to you.
If you review the list above on thermal conductivity you will notice that stainless steel is very far down the list. In fact, it is barely above stoneware and glass. So if it's thermal properties are so poor why are stainless steel pans so popular? Great question, young Jedi.
The answer is found in the magic of modern manufacturing. You see, all stainless steel pots and pans are CLADDED. This is a fancy way of saying that there are layers of metal put together in a a sandwich-like method, and wrapped in a stainless steel envelope (or cladding). And what is the metal that is sandwiched in between the layers of stainless steel? ALUMINUM!
Stainless steel pans have one or more layers of aluminum inside the cladding. If you refer to the ranking of metals for thermal conductivity you will see that aluminum is second only to copper in thermal conductivity. This is a brilliant way to combine the outstanding thermal properties of aluminum with the beauty and ease of stainless steel.
The basic stainless steel pan is a TRI-PLY. This means there are 3 layers in the pan: a heat conducting layer of aluminum sandwiched between two layers of stainless steel. The tri-ply is the most popular stainless steel pan.
But, manufacturers soon found out that they they could add more layers of aluminum in the pan sandwich, which had some very welcome benefits. By adding more layers they could increase the thermal conductivity as well as reduce the hot spots (or, if you want, increase the heat distribution). So now we have 5-PLY and 7-PLY stainless steel pans. These are "better" than tri-ply pans, but at a higher price point. The 5-ply and 7-ply pans feel more substantial. And they are.
Make sure you know if the stainless steel pan you are thinking of purchasing is a 3-ply, 5-ply, or a 7-ply. Be an educated consumer.
I started with the stainless steel pan because it is so popular, but we should immediately digress back to the king of pans: Copper. Copper is beautiful, cooks like a dream and become family heirlooms. But they don't come cheap. In fact, if you find a copper pan that is "cheap" (new, notused one) you should run away. There is no faking the fact that copper pans are expensive - and you want a reputable vendor if you are going to spend that kind of money.
Two things to remember about copper pots and pans:
- While they have outstanding thermal qualities they make a poor cooking surface. They are VERY REACTIVE. So you will find most copper pans have a layer of another metal on the cooking surface. The traditional metal cooking layer for copper is Tin. This metal has excellent thermal properties which don't detract from the core copper. Recently, manufacturers have been using stainless steel as a cooking surface. This has slightly less thermal properties than the tin, but it is easier to keep clean.
- Copper oxidizes like crazy. So, if you want your copper pans to stay coppery (instead of turning green), you will be polishing these regularly.
Moving down the list of thermal conductivity we get to #2: Aluminum. Why aren't there a flood aluminum pans on the market? They have great thermal properties. They are light and easy to maneuver. And aluminum is inexpensive. Great question, Grasshopper! I have one work for you: ALZHEIMER'S.
You see, it has been suggested that aluminum can cause Alzheimer's Disease. While this is true, no link has ever been made between using an aluminum pan and contracting Alzheimer's. Nonetheless, manufacturers stopped making pure aluminum pans. Aluminum pans are now available in 3 main categories:
- Anodized Aluminum. This is a manufacturing process which, essentially, keeps the aluminum from reacting (leeching) into the food when it is cooked. My head hurts when I try and understand the chemistry and physics on how this works. But it does work. You can buy some very good anodized aluminum cookware.
- Non-stick. Most non-stick pans are aluminum pans with a coating of non-stick material on the cooking surface. I will cover this in the Non-stick section further down in this post.
- Stainless steel. As we noted above, stainless steel pans are, mostly, an aluminum pan with a cladding of stainless steel. A brilliant solution to the problem.
Cast Iron pots and pans are wonderful additions to your cookware collection. They are virtually indestructible, offer incredible heat retention characteristics, and are very reasonably priced. If you want to sear a steak, or slow cook a stew, you would be hard pressed to find a better alternative (except for the carbon steel pan, discussed below).
While the thermal conductivity of cast iron is much lower than that of copper or aluminum, once it comes up to temperature it holds that temperature evenly for a very long time. This is what makes it great for searing, and for slow cooking. In both cases you want to maintain the temperature through the cooking cycle.
The challenges in using cast iron are principally:
- They are a porous, iron-rich metal which means that they must be "seasoned" to keep them from rusting. Seasoning is a very easy process and, once a good seasoning is achieved, they get better the more you use them.
- They can be reactive with certain foods (mostly acidic foods). This means they have the potential to impart unwanted tastes into food cooked in the pan. You will want to avoid using cast iron for tomato-based, or wine-based, foods.
- They are heavy. 'Nuff said.
- Because the process of casting (pouring molten metal into a mold) the cooking surface can be rough (rather than smooth). This can make it difficult to cook things like eggs.
These challenges notwithstanding, you would be hard pressed to find a better material for a Dutch Oven than cast iron.
Enameled Cast Iron
Enameled Cast Iron puts a layer of material on the cooking surface. This makes cast iron totally non-reactive. This is an excellent solution which provides you with all the thermal benefits of cast iron while removing the downside of possible unwanted flavors permeating your dish.
If you have been in our store, you know that carbon steel pans are a personal favorite of mine. "Mike's Favorite Pan" is a carbon steel pan. Carbon steel has the same positive characteristics of the cast iron pan, but with a few less drawback.
Carbon steel is the same metal that is used in cast iron pans - it is just the manufacturing process which is different. Rather than pour molten metal into mold and cast it, the metal is rolled into a sheet. This sheet metal is then formed into the shape of the pan by bending and shaping it. The resulting pan has the following benefits vis a vis the cast iron pan:
- A smooth surface, when compared to the cast iron pan. This surface is perfect for whatever egg dishes you want to make. In fact, the carbon steel pan is the classic omelet pan of the traditional french chef.
- The carbon steel pan does not weigh as much as the same size cast iron pan. Lighter is good.
- They are great for searing. You can heat a carbon steel pan to high temperature just like a cast iron pan - but it's smooth surface yields a better Maillard Effect and the food releases naturally when a perfect crust has formed.
- They are easier to clean than cast iron pans.
- They are slightly less prone to reactive transfer of taste to the cooked food.
While these benefits are real, the carbon steel pan does have the same requirement for seasoning as does the cast iron pan.
Modern manufacturing has given us a new class of cookware: Non-stick. While this seems to be a God-sent solution to common cooking problems, there are some issues which we need to be aware of.
All non-stick cookware is made by applying a coating of material on the cooking surface of the pot/pan. The original material used for non-stick cookware was Teflon. IF YOU HAVE AN OLDER TEFLON PAN YOU SHOULD THROW IT OUT IMMEDIATELY! Teflon contains a carcinogen that leeches out when heat is applied. This chemical is known by the acronym PFOA. YOU SHOULD ENSURE THAT ALL YOUR COOKWARE IS PFOA-FREE.
In response to this danger, manufacturers have switched to using ceramic-based coatings for their non-stick pans. Ceramics are inert and cannot transmit any chemicals into the food. Some of the ceramic coatings are layered onto the pan (and usually have a distinct color), or are infused into the base metal of the pan.
Non-stick pans are great for cooking eggs and you will probably want to have at least one non-stick pan in your cabinets.
Ceramic and stoneware are probably the oldest cooking vessels known to man. And they are still around and still provide a reasonable option for your cooking options. Ceramic dutch ovens are awesome. Baking dishes as well. And there are some great ceramic pieces which can be used on your grill. Did I mention Pizza Stones?! Or Tagines?
While ceramic cookware takes the longest to heat up (due to it's low thermal conductivity), they are quite good at long cooking chores. And they are MUCH lighter than their metal counterparts.
Yes - you there is glassware you can cook in. Glass has the same thermal properties as ceramic cookware. Glass roasting pans and cake pans are a favorite item. And they are significantly lower in cost than any other item on this list. Who doesn't have a glass roasting pan in their home?
I hope this was helpful. Look for the next installment of Cookware 101 - where we will go through the different shapes of cookware (e.g. What is the difference between a Sauce Pan and a Saucier?).