Maple Syrup Boiling / Evaporator Pans: use Mild Steel or Galvanized or What?

A. Hi Tom. I hope your natural-origin coating works, and Aaron Schlueter says below that it will. But unfortunately it wouldn't surprise me much if those layers of burned fat were somewhat soluble in water and watery solutions.

It might be a good idea to conduct a small-scale experiment like boiling water in a seasoned skillet, or putting a small seasoned skillet into a good-sized pot and filling it with water and boiling it, to see if you see a skim of grease on the top of the water. Periodic application of butcher's wax might also work, but there are certainly 'food-safe' clear coatings.
Luck & Regards,


Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

A. It depends on the status of the galvanize and on your opinions regarding "safe". There are some very informative letters about galvanized grills and smokehouses in the archives; if you use the search engine here on the site you should be able to find the answer to your question.

The galvanize itself would be okay (I think - I'm not a galvanizer and do NOT speak as an expert), but a lot of times the parts are coated with a top layer of chromate - which often contains hexavalent chrome, a very bad thing to have in contact with food. Like I said - use the search engine.

Good luck!

A. Hi, Sean. People eat off of cast iron pans & griddles all the time; they bake on steel cookie sheets; they picnic publicly, grilling hot dogs on steel fireplace grates. They continue to use nickel plated serving spoons and utensils long after the nickel is worn off and the underlying steel is rusting. They carve their turkeys with steel knives. Some of us receive our water through steel pipes. So I wouldn't worry about making syrup on a steel pan.

But if someone wants to look for reason to worry: How do we know it's truly mild steel and not leaded steel? Or that it wasn't cadmium plated and incompletely stripped? Or that the sheet was once used as a part of an Agent Orange spreader or as a drip pan for a PCB transformer? In other words, no matter what qualifications someone has, they cannot issue any guarantees from a distance. But if it's plain steel, and clean, odds seem very good that it should be just fine. Good luck.

A. Sean, I assume you're worried about what might leach out of the mild steel into the maple syrup. You shouldn't be. I've got baking pans made out of mild steel, and a couple of nice sharp knives that are made out of high carbon steel, and possibly a few more kitchen implements. I've got a favorite frying pan made out of cast iron- think mild steel with 2% instead of 0.2% carbon, and you're not far off. You probably have some pots & pans made out of non-stainless steel as well. Yeah, the stuff rusts ... so keep it clean, keep it dry, and it will serve you well.

I've been a metallurgist since '78, and have worked in the automotive and aerospace industries, and I've been eating since long before then.

Have fun!

A. Hi Chris. Galvanized means coated with zinc. Zinc is not a toxin ... in fact it's an essential nutrient.

But there is concern about "overdosing" on zinc because it dissolves pretty readily both in acids and in strong caustics, so zinc is not considered "food-safe" as a general purpose surface. Further, some galvanized metal was treated with a very low-concentration of hexavalent chromium -- which is a toxin and definitely not food safe. Finally, galvanizing, especially old galvanizing, could include more lead or cadmium than you would be comfortable with.

It's possible that a given sheet of galvanized is free of hexavalent chromium and low in lead, and that it will not be subjected to acid or alkali when used to boil maple syrup; so if you bought something specifically marketed as a syrup boiling pan it's probably fine. Further, although tin coating is not as common as zinc plating, it is available and looks a lot like zinc plating, and it is food safe; so it's possible that boiling pans purchased for the purpose are actually tin plated.

Personally, if it was an item sold for the purpose, I'd use it without qualms. But I wouldn't simply take a sheet of galvanized steel and form a boiling pan out of it. Best of luck.

Regards,

A. Hi Richard. I don't quite like to use the word "hazard" because hazards ought to be quantified (because everything is hazardous to some degree) and nobody can say exactly what the danger is and how severe it is. So I'd prefer to simply say that galvanized surfaces are not food safe so I think they should not be used for this. Stainless steel or tin plated would be ideal, but plain steel or aluminum would probably be better choices than galvanized. Good luck.

Regards,

A. Zinc coated, solid zinc, or galvanized steel should not be used on hot or cold syrup. The syrup has organic acids that dissolve zinc into the solution, and the flavor is ruined.

A. Hi George. I see no reason you couldn't. But the reduction is usually something like 40:1, which is probably why very large pans and even continuous operation is often done. A non-stick pan holding 2 quarts of sap would reduce to about one jigger of syrup. I'd probably drink at least 3 jiggers of bourbon while waiting for the maple flavoring for it :-)

Regards,

A. Hi Frank. I think boiling baking soda in it for several hours as you did repeatedly is the best way to fix it. Since it didn't work, maybe try letting a citric acid solution sit in it for a day before boiling the baking soda again.

But one final thought: are you 110% sure that the smell is actually coming from the pot, not from the fact that you're heating the surroundings and filling them with warm condensate? Our noses don't tend to be great direction finders. I had a "cat urine" smell in my house which seemed to wax & wane, but turned out to be a dead mouse in the wall. It really wouldn't surprise me if your problem is in the building rather than the pot. Good luck.

Regards,

A. Frank Solinger ... I have an answer for your cast iron and a question for you.
You did not ruin the CI. vinegar mixed with H2O is used in CI for cleaning up rust. It is usually followed up by a SMALL bit of soap and H2O and then rinsing with LOTS of H2O. The next step is to re-season it. There are lots of methods but my most reliable method is to use a VERY LITTLE BIT of Crisco rubbed on to the cooking surface (and exterior) and heating the pot to about 500 degrees (the Crisco smokes at this point) then rub a very little bit more Crisco on. Do this 5 or 6 times. It should darken with each coat until the cooking surface gets black.
Q. Have you made maple syrup in steel while your CI was out of commission? Did you notice any flavor differences? Please let us know, Thank you!

Frank, I missed the part about 8 months with the vinegar. It could have etched the CI or leached into it. Generally they say 15-30 minutes soaking in vinegar. I would re-season and cook some bacon and or fatty meat/ soup in it a few times. That may complete the process and allow the remaining vinegar to escape. Just guessing now but maybe a paste of baking soda [in bulk on eBay or Amazon [affil links] on the cooking surface?

A. Hi Grassa. You are certainly correct about the better heat transfer ability of copper, but copper is not considered food-safe in all circumstances (although it's apparently fine for maple syrup) ... plus stainless steel is cheaper, more corrosion resistant, and easier to clean.

Regards,

A. Hi Grassa,
To elaborate on Ted's response, you'll notice that when copper is used for cookware, it is either sandwiched between layers of stainless (most cookware lines) or plated onto the outside (Revereware). When used as the primary material of the pans themselves (classic French and Portuguese cookware, which I absolutely ADORE), the food contact surface is coated with tin. When the tin layer is scratched or worn through, it has to be reapplied by a craftsman specializing in retinning, which is quite an art [ed. note: see threads 25553 and 29192]. But the protection from an inert layer is critical.
The only exception you will see is egg white whisking bowls which are raw copper. They are always scoured with lemon and salt immediately before use to remove oxides, and then rinsed. And all they are ever used for is fluffing up some egg whites to make souffles and meringues and such, where the contact time is very short, never for actually cooking.
I kinda want to make souffle now :)

A. Hi Kris,
The bare copper zabaglione pan is exactly what I use to make Ganache, and I've never seen evidence after use that the chocolate mix (cocoa, butter, cream -- all fairly neutral pH, and short contact time) has reacted with the copper.

I can't speak to the safe contamination levels for ingesting copper so to give my very unscientific answer to the latter part of your inquiry, I have to quote the great Patsy Stone: "Not dead yet, sweetie darling!"

Also, I consume a lot of ganache. I expect to keel over of coronary failure long before the copper gets me.