This May, my friend Shae is shutting down her blog, Hitchhiking to Heaven. She has offered up some of her old posts so that they can continue to live and be useful after HtH closes its doors. This piece about preserving in copper is one I’ve referenced repeatedly over the years and so I’m delighted to bring it over to Food in Jars.
Some preserving experts swear by the centuries-old French practice of using unlined copper pans to make the finest preserves. Others swear it off, calling it unsafe.
When I outgrew my old 6-quart stockpot, I heard a copper jam pan calling my name, but then I got hung up worrying about poisoning people. (I hate it when that happens.) So is copper safe or not? It took some time to unravel the mystery. Here’s what I learned.
Why Use Copper?
There’s one big reason to use a copper jam pan: You won’t find a better heat conductor anywhere. Great heat conduction equals shorter cooking time — that means you spend less time boiling away the flavor, color, and texture of your fruit.
There are other features of a jam pan that will help you cook your mixtures quickly and evenly, most notably shallowness and slightly flared sides. (The slant helps moisture evaporate; it doesn’t run back into the mixture as with vertical sides.) Copper jam pans have it all.
I admit that I was also caught by the romance of using a gorgeous, heavy copper pan to make my jams. While I was shopping for copper, more than one person said to me, “This pan is something you’ll pass on to your heirs.” I don’t yet know who my heirs will be, but I was intrigued. We’re talking tradition here.
Finally, a good copper pan really lights up the kitchen. For a practice like jam making — as much art as science — investing in a tool that inspires you every day is a legitimate consideration.
When Copper’s Safe — And When It’s Not
Getting right to the point, an unlined copper pan is safe when you use it to cook a mixture of fruit and sugar. It’s not safe for fruit without added sugar. The road to this conclusion was a long one, and I’ll give you only an abbreviated version of the journey. (I know it doesn’t look abbreviated, but trust me.)
Confession: I somewhat impulsively spent a good chunk of this year’s tax refund on a copper pan without giving a thought to safety. But not long after I made my first batch of copper-pan jam, Stewart started pinging me with little emails about copper toxicity. He’s careful that way.
The more I read about cooking with copper, the more I worried about sickening myself and my loved ones with symptoms like fever, vomiting, and convulsions. (Here’s one source for more than you want to know about how too much copper can screw you up.)
When I turned to my preserving guides to learn more, I got confused. Christine Ferber, in Mes Confitures, states that she always uses a copper pan because of the superior heat conduction. On the other hand, in The Joy of Jams, Jellies, and Other Sweet Preserves (a book I love and use a lot), American expert Linda Ziedrich says copper’s not so smart:
The interior surface of the pan should be made of a substance that won’t react with acidic foods. This excludes iron and aluminum. Although French preserving pans were traditionally made of unlined copper — because copper would react with acid and thereby enhance gelling — such pans are frowned on today, at least in the United States, because copper can be toxic.
What’s the deal? Clearly, copper jam pans have been used for centuries without causing a mass die-off of jam eaters. But fruit is acidic and we know that acid and copper shouldn’t mix. Help!
For the final word, I contacted Rachel Saunders, former proprietress of Blue Chair Fruit. Rachel made all of Blue Chair’s small-batch preserves in unlined copper kettles — and she had the clearest, most practical answer to my question:
The key to using a copper pan is to put only the jam mixture in it — put the fruit in the pan only after it has been combined with sugar. Putting fruit in the pan on its own will cause the fruit to react with the copper and can be dangerous. I have made thousands of jars in our copper pans, and the results are excellent. The high concentration of sugar in the mixture prevents toxicity.
So there you go. Sugar prevents the acidic reaction. That’s why you should never prepare or macerate your fruit in unlined copper. Use glass or ceramic instead.
The truth about copper was good news and bad news for me. Good, because I can use my new copper pan for lots of preserves. Bad, because some won’t work.
I sometimes make jam with Pomona’s Pectin — a citrus-based pectin that allows you to dramatically cut the sugar in a recipe. The catch is that you add the sugar to the mixture very late. You prep and boil the fruit well before you add the sweet stuff — exactly what you don’t want to do with a copper pan. Boo. I still needed a pan I could use with my Pomona’s recipes. For that, I chose the Demeyere 10.6 Quart Maslin pan — stainless steel with a heavy bottom — which I’ve happily used for many years.
How to Care for a Copper Pan
When it comes to cleaning copper pans, it’s fine to keep things simple. The jam makers I talked to keep their pans clean and dry, but they’re not fussy about a little natural, penny-colored patina.
Rachel Saunders advises rinsing your pan right after you use it, cleaning it with a very mild detergent, and drying it at once. These simple precautions will help to prevent any unwanted reactions. If you do ever notice evidence of oxidation on your pan — a sort of green, mustardy ick, as I understand it — you can use a very gentle scouring pad to get rid of it.
Copper pans can take some abuse. From a safety perspective, there’s no need to worry about some scratches or scorching. Feel free to crank your copper to the highest heat. That’s what it’s made for.
Of course, if you want to keep your pan pristine, there’s lots of information out there about how to do it.
Want Copper? Sources for Your Fix
If copper grabs you like it did me, you’ve got a few choices to make: What brand? What size? How much are you willing to pay?
The brands you can most easily find and order in the U.S. are Mauviel, Matfer Bourgeat, and Baumalu. The smallest pans are around 10 quarts (Matfer makes one of these). None of them are cheap. Matfer is the lightest and least expensive of the bunch — you can find one for a little more than $100 — but keep in mind that lighter weight means lower quality.
A couple of places to start your search:
As with almost everything else on the planet, you can find Mauviel pans on Amazon.
For an interesting assortment of new and used pans, it’s fun to browse eBay. Search for “copper jam.” You may have to sort through a few pairs of copper-colored Nike Space Jam sneakers, but those are the search terms that will bring up the greatest number of copper jam pans, kettles, pots — whatever the seller decides to call them.
If you want to walk into a store, you can usually find the 11.6-quart Mauviel pan in stock at Williams Sonoma or Sur La Table. (Note from Marisa – If you’re local to Philadelphia, Fante’s in South Philadelphia typically has some lovely copper pans in stock.)
Of course, you don’t need copper to make good jam but, without a doubt, a quality pan can enhance your jamming experience. I love my copper pan. I feel almost like it talks to me — offering recognizable sights and sounds to indicate the phases my jam goes through as it cooks, especially when it’s ready to come off the heat. My old, dark pot didn’t provide the same clear signs about what my jam was up to. I say if you want copper and you’re willing to follow a few simple safety and cleaning precautions, go for it.
This piece was originally published on Hitchhiking to Heaven on June 1, 2010 and was written by Shae Irving.
I originally came across this article when I was trying to find evidence to convince a friend that she could safely use her traditional unlined polenta pan. I think the most important point to make – other than not cooking high acid food in unlined copper – is to make absolutely certain that the cooking surface is clear of any tarnish or verdigris before using it.
I was lucky enough to pick up an 11 qt Mauviel jam pan and a 2 qt Mauviel sugar pot within a couple of weeks of each other on Facebook Market. I’ve been using the sugar pot to make some small batches of jam since I find it to be more fun messing around experimenting with flavours. I’m very impressed with how the jams I’ve made this way have set without my having added any pectin.
Thanks for this. I was gifted a gorgeous copper jam pan for Christmas. My question is, if I am making jam that has a lot of sugar but also requires a few tablespoons of lemon juice, is it safe to use the copper pan (as long as I mix the fruit and sugar together before adding to the pan? Please advise – I appreciate it!
As long as you mix the lemon juice in with the sugar and fruit before pouring it into the copper pan, you should be fine.
My copper pan(ebay purchase)changed my jam game. Straight up. And it also inspires me to do more. It helps that I have an apricot tree, my neighbors on 2 sides plums, so sugar and jars are my main expense. I appreciate your clarification of always put fruit with sugar in the pan to avoid toxicity. I mainly use your recipes along with Rachel Saunders. Your tomato jam has put me on the map1
I’m so glad this post was helpful! And that tomato jam is just so good!
I used my matfer copper jam pot once, and have not used it since. I cooked a whole pot of apple compote for my Normandy Apple Tart and had to first sauté the Granny Smith apple cubes in butter, then added sugar and lemon juice. It was at the end of the cooking that I noticed the compote had turned green from copper leaching. I tossed the whole compote away. Very sad.
Copper pots have to be used in a very specific way to be safe. I’m sorry that your compote was ruined.
Here’s some reliable information from the National Institute of Health:
https://www.ncbi.nlm.nih.gov/books/NBK225400/ (It’s a bit of a read and it concentrates on acute copper poisoning. Still, it reviews cases of copper poisoning from a variety of containers. )
Also see: https://www.healthline.com/health/copper-toxicity (It’s straight forward and addresses the issue more extensively.
The bottom line is that copper is toxic at varying levels to humans and animals. It appears that poisoning most often is ingestion of copper from contaminated water or the leaching of copper from food or liquid in copper vessels.
The leaching of copper from bare copper pots is enhanced by the acidity of the foods placed in them. Think about it – copper can be cleaned with lemon juice because lemon juice is acidic and it dissolves and removes the oxidized copper molecules from the surface. Acidic foods do the same in those bare copper pots. Now add in high heat when using a copper pot an you’ve only increased the chemical reaction.
Most modern pots are lined with non-reactive surfaces, such as stainless steel or ceramic for the single reason of reducing the potential of leaching copper into food cooked in them. Copper is a great metal for pots as it is a very good conductor of heat and heats evenly. That’s why many good (and pricey!) skillets and pots have a copper core in there base.
It appears one way to reduce the risk of copper leaching is to reduce the acidity of the foods you are cooking in your bare copper pots. What about adding sugar? Well, chemically sugar does not reduce acidity but it does reduce our perception of it’s taste (adding sugar to bitter acidic tomato sauce, coffee or tea makes it *taste* less acidic. The chemistry to reduce acidity is to add an alkaline substance, such as baking soda. That’s why baking soda is added along with baking powder in some baking recipes with acidic ingredients like vinegar or citrus. It lessens the acidity so the baking powder can do it’s work to make your bread, pastry, etc. rise. I don’t know how much baking soda you would have to use for to reduce the acidity in your jam or what that would do to your recipe!
Use your best judgement but for me, it’s all about the safety and either eliminating or at least reducing the risk. I would think the risk here could be reduced by limiting how often you use your unlined copper cooking vessels and how often you eat foods prepared in them. I think it would be wise to consider your own person circumstances. Are you pregnant or nursing? Are you immunocompromised? Do you have an autoimmune disorder? Is your body already stressed with recovering from an illness or injury or do you receive treatment for a medical illness that already taxes your body? Be smart. It’s not always how likely something harmful will happed, but the severity of the consequences if it does happen. Think seatbelts. Are you likely to get in an accident every time you drive. Of course not but we wear them every time because the severity of the consequences if we do get into an accident, could be so severe (to us, others and our wallets),
Enjoy your copper pots but carefully consider your risks and consider verifiable information from RELIABLE sources – medical, laboratory and testing sites and even your own physician – not just someone online who says, “sure, it’s fine . . . we do it all the time.” You’ll find lots of that : ). I’ve done my research but I am NOT an expert nor a chemist and I’ve only given you a snapshot of what I’ve found. I’m sure there’s a ton of relevant and reliable information available if you look for it.
Incredibly helpful article – thanks! I am just about ready to take the plunge for a copper jam pot.
A few (hopefully) quick questions: Is there a minimum amount of sugar required? I tend to use less sugar than most recipes call for – for instance, my strawberry-rhubarb jam has ~16 cups of fruit and ~2.5-3 cups of sugar. (Some of my jams are by weight and have ~4:1 fruit to sugar ratio.)
Is it best to macerate the fruit for a couple of hours before placing in the copper jam pot?
Also, if using an unlined copper pot, should I leave out the lemon juice that many recipes include?
Much appreciated!
I find that a 4 to 1 ratio of fruit to sugar is sometimes a little too low for the copper pan. I have had a metallic flavor extract into the jam at that level of sugar. I find that you don’t want to drop below 3 to 1. It is best to fully macerate the fruit and sugar before putting it in the pan, and using lemon juice isn’t an issue as long as there’s enough sugar.
I so wish I had researched before asking for the beautiful Cooper Mauviel jam pan. We use SureJel low sugar pectin, which does give the recipe with 4 cups of sugar instead of the normal 8. I see no reason the sugar could not be added all at the beginning to help protect the jam from the copper. (I’m amazed that these pans are made without being made more safe.). I’m not sure how this differs from Pomona recipe? We have been making jam for years in a nonstick stock pot and just wanted the advantages of the more open pot. No idea that there was more than the copper version or that copper toxicity could be an issue!
Sorry for typos. My sisters say it keeps them mentally active working out what I mean.
I just made some sweet orange and lemon marmalade in my late mothers copper jam pan. Prior to buying this, in her 70s, we ussed a huge, oval, enameled pan for the tons of jam plus bittled fruit we did every autumn. (We had an acre garden eith fruit trees, greenhoyses and himalayan blackberries in the hedge). Then I recalked reading in my preserving book not to use unlined copper. Thanks for this article. My marmalade tastes fine by the way. But next batch will only use the pan to boil thecsugar mix. (I live in Andalucia and neighbours and my Spanish daughter in law have inundated me with citrus fruit. ) re pectin that my mother used innthe UK. No one in my village has ever heard of it. It isnt in any of the supermarkets either. Ah well. Note. In mainland Europe all jams, (US jellies) are called marmalade, Mermelada in Spanish.
Apple Butter in Appalachia is made in COPPER kettles, not brass.
Brass is a combination of 2 metals: copper and ____ (research). I’d research it carefully before using brass.
Late to find this post but still learning about my heirloom copper pan, big enough for 8-12 8oz jars of jams (more if I wanted to – but then the canner wouldn’t fit on the stove) Wish I could post a pic. Its a beauty
Hello thank you for your article! I am still confused about my chutney I used 5kg of green tomatoes, 2liters of vinegar, 1 kg of sugar 500gr of sultanas and spices. I have started by boiling the sugar and the vinegar and the sultanas and when boiling I added the tomatoes. I used an unlined copper pan so now I’m thinking that the sugar and sultanas weren’t enough in quantity to make up for the tomatoes and vinegar acidity?? Do you think it’s safe to eat or should I throw it all away? Its 17 post and 3.5hours of cooking…😟
Taste it. If it tastes highly metallic, then you have an issue. If it tastes fine, it is fine. It’s not a safety issue, it’s a flavor issue.
I bought a beautiful, old copper jam pan and it has been calling out to me to use it. I just saw a wonderful recipe for a pumpkin or butternut squash jam that is of Middle Eastern origin. It calls for 1 1/2 kg pumpkin, 2 oranges juice and zest some seasonings and 1 kg of sugar. It doesn’t say to macerate the pumpking overnight in the sugar, just to put all the ingredients in a pot and cook until the pumpkin is translucent and it has reached the right gelling stage. If I were to macerate the pumpking overnight in the sugar do you think it would be safe to use in my glorious copper pan?
I would certainly macerate the pumpkin with the sugar for a little while. However, there’s a bigger issue with that recipe and that is that pumpkin is very low in acid and so the resulting jam that you make will not be safe for canning.
Hi,
I was sad to pass on a beautiful French copper jam pan. However, since I only like low sugar jams and planned to use Pomona’s I did not click buy.
Instead I took your advice and bought the Demeyere RESTO Maslin Pan – 5Ply 10.6 Qt. Jam Pot.
Hard for this visual artist to decide not to go with the beautiful hammered copper jam pan so hope to hear from you that indeed I made a wise decision, lol.
Cheers,
Anne
I don’t think you will regret getting the maslin pan. It’s such a hard working, useful vessel.
I just got a new Mauviel cooper jam pan for Mothers day and I love it and can’t wait to make some jam.
Would love to know thought do you ever cook anything else in your pan. I’ve read not to cook salted preparation in raw cooper. Thanks Lisa
You really only want to use unlined copper for sweet preserves and candies.
Thanks, Just an old guy
So I think I’ll give my brass jelly pan a go then and let you know how it works (just hope you don’t read about it in the Scottish news!).
I’ve done some reading and brass is a highly reactive material, just like copper. I don’t know if the sugar will prevent the reaction from occurring. Just know that there’s a chance your jam will be inedible.
Folks up here in the mountains have been making apple butter in brass kettles over a wood fire for a couple of centuries. No cases of apple butter poisoning have been reported.
I have a beautiful copper jam pan I purchased last fall – I have looked everywhere for info on it. Your sight has the best information.
Do you know if candy would work well in jam pot? Toffee? Caramel? Fudge?
Copper is traditionally used for candy making. I’ve never tried it, though.
So for once sugar is the hero, not the villain! =)
It’s true!
It would be interesting to make two batches of the same jam, one using a copper pot, the other a non-copper pot. Then have both batches analyzed and see what the difference is in ppm of copper. And then determine if there might be a health hazard with that data.
This would probably not be a cheap experiment, but interesting. With two little kids in the family, it would be perhaps essential.
It’s an interesting suggestion. I don’t have the budget for it, but I wonder if a copper cookware manufacturer might take it on?
Very useful information. Which reminded me … I have a lovely old brass jelly pan. Very heavy, very old – not shiny and ‘ornamental’ but a practical piece of kitchen equipment that was probably used over an open fire in a crofters cottage in bygone years. Is brass safe for jam making? Any precautions?
Hmm. I’ve never heard anything about cooking in brass. You probably want to do some deeper investigation before proceeding.
I use my Mauviel copper pan for most of my European style soft non pectin jams that macerate overnight with sugar. I usually bring the fruit and sugar to a simmer in the pan, pour into a non reactive bowl (ceramic or Pyrex) to sit overnight and make the jam in the copper pan the next day. Copper pans clean beautifully with just hot water and a scrubbie. Tarnish is easily removed with a little acid (vinegar or I often use the half of a squeezed lemon I’ve used for lemon juice as an impromptu little scrub brush) with some salt as a mild abrasive. It takes very little work to keep it clean – you are only using it for fruit and sugar – all easily soluble in hot water. These pans cook like a dream, never scorch, heat up and cool down quickly. Usually 1 kg fruit such as raspberries will set in about 10-12 minutes without any added pectin.
They really are a joy to cook in when you’re making those traditional preserves.