Copper Cookware: 11 Burning Questions Answered!

A Definitive Guide to Copper Cookware

I was recently on a guided tour of a chocolate factory that makes gourmet, hand-made chocolates in small batches. While stuffing my face with free samples, I noticed something.

The lady operator was stirring melted chocolate in….. an UNLINED copper drum!

Unlined Mauviel Pot

“Unlined copper? But isn’t that dangerous?”, I asked, suddenly worried about the generous portion of samples I had ingested.

The tour guide smiled, shook her head and proceeded with the speech. Hmm, my curiosity was piqued.

The next day, one of my readers emailed to ask about re-tinning her copper pans and if tin lining is safe.

Re-tinning? Do people still do that?

Obviously, there was a lot I didn’t know.

All I knew was that copper cookware was something I seriously needed to understand:

Is it safe?

Is it good?

And does it really need to be lined with tin or something else?

This is the result – the most definitive guide to copper cookware that you will ever need.

Read on…..

 

1.     Why use Copper cookware?

Copper cookware is like the Rolls-Royce of all pots and pans!  Not only is it aesthetically appealing, it is the ultimate conductor of heat!

A copper pan will heat up quickly and evenly along the bottom, walls and edges with no hotspots or uneven heating.   This means the top of the pan will be as hot as the bottom so your food heats and cooks evenly.

To give you an idea, copper has a thermal conductivity (i.e. ability to conduct heat) that is TWICE that of aluminum (which is considered a good conductor of heat anyway) and almost 20 TIMES that of stainless steel!

This means a copper pan will heat up twice as quickly as an aluminum pan and 20 TIMES as quickly as a stainless steel pan.   

Not only is that saving you time, but is a much more efficient use of energy.

Copper electric wires work for the same reasons as pans

If you’re curious about how the most common cookware materials stack up against each other in terms of thermal conductivity (measured in W/m2k), here’s a comparison:

Copper401 W/m2K
Aluminum237 W/m2K
Nickel91 W/m2K
Cast Iron:80 W/m2K
Tin:67 W/m2K
Stainless Steel:14.2 W/m2K

Source:  http://www.tibtech.com/conductivity.php

This excellent conductivity means a copper pot will also cool down quickly if needed.  This gives a lot of control for dishes that are made at strictly controlled temperatures – like sauces and risottos for example. It also explains the popularity of Moscow Mule mugs.  Since copper quickly takes on the temperature of the chilled drink, it heightens the enjoyment and the experience!

Copper cookware is well suited for the chef or home cook who wants precision and control in their cooking.  It is for this reason that world renowned chefs like Julia Childs favor copper cookware above all other pots and pans.

As a side note of interest, Julia Child’s entire kitchen including 30 well used copper pans are now on display at The National Museum of American History.

Fun fact: A museum at the University of Pennsylvania displays a copper frying pan that has been dated to be more than 50 centuries old. (copper.org)

 

2. Why is copper cookware usually lined?

Copper is a trace element that is essential to the normal functioning of the human body.  In fact, it is present in common foods like seafood, kale, mushrooms, nuts, beans, avocados to name a few.

So why all this hoopla about lining copper pots?

The reason for that is that Copper is not inert.  It reacts with acidic foods like tomatoes to create reactive copper salts called verdigris poison that can make you quite sick, with symptoms like nausea, diarrhea, and vomiting.  If copper is ingested in a large quantity or consistently over some time, it can cause problems in the liver, stomach, and kidney.  It can also cause anemia (source: cookingforengineers.com).

Many countries and states don’t even allow unlined copper pans to be sold.

 

3. Is it safe to use copper cookware then?

In a word, yes!

You really don’t need to worry about copper poisoning from cookware.  Almost all copper cookware sold commercially is lined with stainless steel, tin or nickel. Unlined copper cookware is available primarily in the form of jam pans and mixing bowls for beating egg whites.  See section on using unlined pans for more.

So, as long as the interior of a copper pan is coated with an inert lining like tin or stainless steel, the lining prevents any reaction between copper and acidic food and it’s perfectly safe to cook in that copper pan.

As a point of interest, according to this article on Copper.org, acute copper poisoning is a rare event, caused mostly by accidentally drinking a solution of a copper salt …. which most of us are not doing!  Additionally, chronic copper poisoning, which means small and continuous exposure over an extended period, is also rare because a healthy body has the capability to excrete excess copper and maintain the balance in the body.

 

4. Why was tin lining so popular for copper pans?

In the words of a devout home cook friend, copper cookware with tin lining is ‘pure tradition’!

Tin is considered the original non-stick coating material – as non-stick a cooking surface as can be found.  It is chemically inert, which means it does not react with any food, nor does it impart any flavor to food.

If you noticed the thermal conductivity table above, you’ll see that tin is a much better conductor of heat than stainless steel.  Which means that the effect of tin lining on the performance of copper cookware is minimal.   It also means that there is less chance that the tin lining will de-laminate (which means separate) from the copper pan, something that can happen with a stainless steel lining.

Another advantage that tin offers is that copper cookware with a damaged or old tin lining can be ‘re-tinned so that the pot can last for generations.

 

5. What is re-tinning of copper cookware?

Over time, tin-lined copper pans will eventually need to be re-tinned, i.e., have the tin lining redone.   After how long depends on usage and care.   Some people get decades of use out of their tin-lined pots, others just a few years.

Re-tinning of copper cookware involves scouring off the old tin and corrosion and application of a fresh coat of melted tin.  It is truly a lost art and has virtually disappeared from the developed world where everything is disposable.

 

6. Is tin-lining safe on copper cookware?

Absolutely yes!

Tin cans got a bad rap in recent years because of the lining in the cans which contains Bisphenol A (BPA) which is a harmful plastic.

Tin, on its own, is an inert metal which does not react with, nor leach into food.

Tin melts at about 450F, which means that the lining on a tin-lined copper pan would deteriorate at that temperature and melt, possibly emitting fumes.  Three points of interest:

  1. A pan would only reach a temperature of 450 F if it is heated empty. No coated or lined pan, be it Teflon, ceramic or tin lined, should ever be heated empty.  So, if you’re doing that, then yes, the coating will get damaged.
  2. At 450 F, most cooking oils would be beyond their smoke point so if you are heating your pans/food to that level, then your food is probably burnt anyway.
  3. If by accident you did heat a tin lined pan to that point, there is no known danger of tin fumes or metal fume fever caused by tin. (Wikipedia).

Now, having said all that, it is important to note that tin is a much softer metal which means it can scour off easily.  So take a few precautions if you use tin-lined copper pans and you will get years out of your pans before you need re-tinning:

  1. Use medium heat and don’t over heat an empty pan
  2. Use only wooden or silicone utensils so that you don’t scratch through the tin to expose the copper.
  3. Avoid hard scrubbing or scouring that can wear down the tin coating

If you see that the lining is coming off and copper starts showing through, avoid using those pans till you can get them restored.

 

7. Can I use unlined copper cookware for anything?

Unlined copper bowls are used primarily for baking as mixing bowls, for making jams and candies

First, let’s talk about beating egg whites.  Apparently, egg whites will beat up to a significantly higher volume when whisked in a copper bowl.

But is that true?  Is a copper bowl really better for whipping egg whites?

According to CEH.org, yes.  It’s actually a chemical reaction between the copper and the whipped egg whites that creates a much more stable foam.    If the term ‘chemical reaction’ has you worried, don’t.  Beating egg whites in copper bowls does not present any danger to you and while it would be outside the scope of this article to explain the chemical reaction, you can read all about it here.

Unlined copper pans are also used to make jams.  According to traditionalists who swear by using copper pans for making jam, copper is THE pan for making jams.  Once the fruit has been combined with sugar, it does not react with the pan and the little amount of lemon juice is apparently not enough acid to cause a reaction.   So the trick is to combine the sugar with the fruit BEFORE it is added to the copper pan.

Because of the excellent heat conductivity of a copper jam pan, it means the fruit has to cook for a shorter time, preserving the flavor, color and texture.

So, to summarize: Copper Jam Pan = Better Jam

Last but not least, let’s get back to the use of copper pans when making candies and chocolate.  Personally, I needed to get an answer to the question that had been burning in me ever since my visit (above) to a chocolate factory.

Turns out, candy makers have been using unlined copper kettles for centuries for making sweets.  Sugary foods like candies, chocolate, and the aforementioned jam, do not react with copper.  The superior heat conductivity of a copper pan allows great control when it comes to heating and quickly cooling down a confectionery, especially when caramelizing sugar.

mauviel copper skillet with stainless steel lining

8. Tin-lined or stainless steel lined?

I get asked this question so often that it deserves its own section here:

“Should I get tin-lined or stainless steel lined copper cookware?”

There’s no straight answer and it really boils down to personal preference and cooking choices.  Anyhow, here is my analysis and conclusion:

Refinishing

Tin: If the tin lining gets scratched or worn, it can be refinished again and again so that the pan is like new again.

Stainless Steel: If the stainless steel lining separates from copper due to uneven amounts of heat, the pan is ruined.

Maintenance

Tin: Tin is softer than steel which means it requires special care to prevent it from getting scratched and worn. Which means don’t heat the pan empty, don’t use metal utensils and don’t scrub too hard.

Stainless Steel: Stainless steel can withstand a lot more use and abuse without damage.

Melting point

Tin: Tin melts at about 450 F, a temperature that is relatively easy to attain on a kitchen  stove.

Stainless Steel: Stainless steel melts at over 2500 F, meaning little chance of it melting in a kitchen.  This means you could sear a piece of meat on high with little worry.

Heat conductivity

Tin:  Tin is a better conductor of heat than stainless steel.  About 4 times better.  Which means your pan will heat up quicker and cook the food faster.

Stainless Steel: Stainless steel takes a bit longer to heat up than tin.  In actual use, however, users report that the difference is only marginal.

 Convenience

Tin Yes, tin can be restored.  Again and again.  But unless you are handy and want to deal with melting tin ingots, restoration is a lost art with few artisans who still do it.

Stainless Steel: Stainless steel lining doesn’t much in terms of maintenance so is much more convenient.

Conclusion: In the humble opinion of The Cookware Advisor, if you are debating between tin-lined and stainless steel-lined copper cookware, my choice would be Stainless Steel lined.  I personally prefer low hassle cookware and stainless steel lined copper cookware fits the bill.  It is more durable, does not need the same level of maintenance and the difference in performance is only marginal.

 

9. Why is copper cookware so expensive?

Firstly, Copper is a much more expensive material than stainless steel or aluminum.  In fact, according to the Copper Development Association Inc. (copper.org) it is a semi-precious element.  In fact, copper is considered the benchmark among semi-precious metals and is often quoted as a leading indicator of economic growth.

Secondly and maybe more importantly, Copper cookware is the cookware of choice for elite chefs.  This is because of its excellent heat conductivity, even heating, and beautiful appearance.  It is therefore positioned as a prestige item and priced accordingly.  Good quality copper cookware is definitely not intended for the mass market.  The higher price tag only helps to make it the exclusive product that it is today.

 

10. How to clean copper cookware?

While copper cookware looks beautiful when its new, over time, the exterior of the pot gets tarnished with a ‘rust-like’ coating due to oxidation.  You could get a commercially available chemical cleaner or you could use a more DIY method with things you probably have at home.  Here are some of my favorite methods:

  1. The lemon salt method: Dip half a lemon in some coarse salt and rub over the copper.
  2. The salt, vinegar and scour pad method: coat the pan with salt.  Add vinegar, more salt and let sit for a couple of minutes.   Scrub it off with a scouring pad.  Rinse with water.
  3. The ketchup method: Pour a layer of ketchup. Let sit for a few minutes.   Scrub it off and rinse.
  4. Baking soda and lemon method: Combine some lemon juice with baking soda. Rub into copper.  Wipe off with a dry cloth.

11. What kinds of copper cookware are available today? What are the pros and cons of each?

For this article, I’m going to focus on the 6 main types of copper cookware that are available, ranging from expensive to most affordable. There are other types including nickel lined and alloys with zinc (brass) and tin (bronze) but those are not used much for cooking and are more for decorative purposes.

Interestingly enough, Health Canada actually recommends even using tin-lined copper for decorative purposes only, probably because the lining eventually wears off and most people would not know how or where to get it re-tinned.

 1. Unlined copper

Pros:

  • Beautiful to look at
  • Last forever, often passed down as family heirlooms.
  • Excellent heat conductivity

Cons:

  • High maintenance. Copper tarnishes very easily
  • Reacts with food so use is limited e.g mixing bowls, jam and candy making
  • Expensive

Best Brands for Unlined Copper:

2. Tin-lined copper

Pros:

  • Best combination of metals for heat conductivity
  • Can be restored again and again if the lining wears off
  • Family heirlooms

Cons:

  • High maintenance. Copper exterior can tarnish and stain.  Interior needs to be handled with care as tin lining can scratch or come off while scouring.
  • Tin melts at 450F so pan cannot be heated too high, even accidentally
  • Tin lining will eventually need to be re-applied which is a lost art.

Best Brands for tin-lined Copper:

 

3. Stainless Steel lined copper

Pros:

  • Low maintenance interior.
  • Can heat to high, great for searing meats.

Cons:

  • Slower to heat than unlined or tin-lined copper since stainless steel is not a good conductor of heat.
  • The steel lining can warp or come off (de-laminate) due to the big difference in the heat conductivity of steel and copper. While not likely in a good brand, once the lining de-laminates, pan must be discarded unlike a tin-lined pan which can be restored.

Best Brands for Stainless steel lined Copper:

 

4. Stainless Steel Copper sandwich. (Stainless steel on the exterior and interior sandwiching a copper interior).

Pros:

  • Low maintenance interior and exterior

Cons:

  • Lower heat conductivity than plain copper due to 2 layers of stainless steel.

Best Brands for Stainless steel Copper Sandwich:

5. Tri-ply Copper Cookware with Aluminum core and Stainless steel lining

Pros:

  • Combines superior heat conductivity of aluminum and copper
  • Stainless steel interior is non-reactive and hardy
  • Beautiful appearance with copper exterior and shining steel inside

Cons:

  • More expensive than regular triply cookware because of the copper component

Best brands for Tri-ply Copper cookware:

6. Stainless Steel with Copper Core/ Copper bottom

Pros:

  • Most affordable option in range of copper cookware
  • Combines the durability and low maintenance of stainless steel with the heat efficiency of copper

Cons:

  • Copper is limited to the bottom of the pan unlike copper clad cookware which goes up the sides.

Best brands for Stainless Steel with Copper Bottom:

 

2 Responses to Copper Cookware: 11 Burning Questions Answered!

  1. John Banister says:

    Copper isn’t actually the ultimate conductor of heat. Silver is. Silver is just way too expensive to use for cookware, though. Also, it may be interesting for you to consider the thermal diffusivity chart at the cookingforengineers site, as this value takes into account also the density and specific heat of the metals. The diffusivity copper:aluminum ratio is more like 6:5 rather than the 5:3 ratio suggested by thermal conductivity alone. Sitram Catering and Demeyere Atlantis are known for having comparatively thick copper discs sandwitched in the bottom of stainless pans.

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