You’ve just splurged for a fine piece of heavy copper cookware, perhaps the best cooking tool you’ve ever owned. It’s shiny and bright and ready to take your kitchen performance much higher. Unlike most other cookware, pure, elemental copper and tin are uniquely capable of letting you know how they’re improving every step of the way. It will be evident in the character of the metals themselves as well as the quality of your preparations.
Before We Start…
…it’s worth revisiting something that will have been stated (perhaps boldly) in the use and care instructions that came with your cookware:
Make sure there’s enough liquid or cooking fat in the pan to cover the bottom before applying heat.
Tin-lined copper cookware is extremely energy efficient, so excessive heat risks damaging the tin lining.
Generally, we advise that all lined pans be filled before heating. Doing so will protect enameled iron from shattering (“dinner plating”), stainless steel from delaminating and non-stick surfaces from outgassing toxic compounds. If you have to dry-sear or toast any food, it’s best to use a cast iron or heavy carbon steel pan.
Oh yes - definitely use wooden or silicone implements. Stainless steel tools bully the tin (which is pretty non-stick when it’s new, and only becomes more so with time — meaning, you won’t need to scrape (see below)).
Copper cookware comes with a fine, hand-buffed finish. Buffing metal is in fact microscopic etching which refracts light at all frequencies, resulting in the shine for which new copper is famous. As you first heat the pan, you activate the metal surface and cause it to begin reorganizing itself from a granularly chaotic (i.e., polished or buffed) crystalline structure into a harder, smoother, more uniform lattice of larger crystals (“aggregates”), which visually registers as the patina.
Patina is often confused with oxidation. While the two processes can occur on the same pan surface, influence each other, and represent state changes, patination is a mechanical process (operated on by force/energy) while oxidation is a chemical process (disparate molecules reacting to form new molecules).
The beginnings of patination is often first evident on the bottom of a pan, which makes first contact with heat. This is sometimes wrongly referred to as scorching, which would suggest the copper has burned. It has not; the buffed surface has begun settle down and form larger crystals. As the fine etching diminishes, light refracts along changing parts of the visible spectrum, resulting in the characteristic purple-blue-shifted coloration emerging from the pan base. At Brooklyn Copper Cookware we call this short-lived phenomenon the “bruise”.
What hue of pure copper’s many colorings your pan assumes will depend a lot on how much heat you put into it. Low heat will tend to shift to the red end of the spectrum, as evinced in the pictures above and characteristic of copper crystals organizing slowly. Higher heat and faster cooking will tend to shift to a yellower effect (see below), betraying larger crystal structure and shorter wavelengths of light reflecting from the surface. Generally speaking, you’ll get the same or better results from copper using lower heat, as the pan itself heats thoroughly without squandering energy.
Whether red or yellow shifted, the bruise yields fairly quickly to more uniform development of the copper’s patina. Again, with use the copper is becoming tougher and more efficient, progressively doing everything you count on it to do really well that much better.
It bears mentioning that, irrespective of which color shift your copper is showing, polishing will return a copper pan back to its original orange/pink copper hue.
A copper pan wears its patina like a badge of honor.
Much the same process will occur on the interior tin lining, but whereas copper needs polishing to remove the signs and stresses of its making into cookware, tin emerges from the molten hand-wiping process already shiny. Tinsmiths don’t generally polish linings after they wipe them in, which leaves the evidence of their hand-work intact as the classic wipe marks.
The transformation of tin from molten to solid (“seizing”) forms the bond between the lining and the copper pan body. Like copper, tin’s shine is a visual effect of a complex surface crystallization that will change with use, settling out to a matte gray color signifying a tougher, larger, smoother, highly uniform (“cured”) tin crystal lattice.
You can often see the tin organizing itself into larger crystals as you use the pan. This, again, is completely normal and signifies the working surface is becoming more durable and easier to use.
These effects are collectively known as tin’s patina. Patination is a characteristic common to materials that benefit from use. At Brooklyn Copper Cookware we encourage owners to think of tin (and copper) as they might leather — a bit of conditioning improves its performance, increases its lifespan and mellows its appearance.
With regard to cookware all of this “work-conditioning” is not exclusive to copper, but the thermally efficient nature of pure copper and tin allow the benefits to accrue quickly and uniformly. For many other cookware metals, such as stainless steel, work-conditioning happens slowly or not at all unless a great amount of heat is applied to an empty pan (never recommended), and then the conditioning can be irregular, as below.
Stainless steel has an extremely hard and complex crystal structure; curing and conditioning happen more readily and quickly through the thermally efficient nickel element of the alloy than, for example, through the iron element. These localized regions of bruising (i.e., conditioning) are what become the hot-spots for which stainless steel is unfortunately renowned.
Traditionally, iron handles on copper cookware are treated with a bit of culinary wax before shipping, which forms a “seasoned” finish at room temperature. Handling a handle softens the wax and causes what does not wipe off to penetrate over time, leaving plenty of surface porosity available for additional seasoning. The best quality iron handles for copper cookware are made with a specific process that, with the addition of a tiny bit of carbon and silicon, forms a finely tessellated crystalline lattice and allows them to expand and contract with the copper and tin. This tight crystal lattice has a concomitantly tight surface porosity, which seasons more readily as lipid chains settle closer to each other and link (polymerize) more easily.
With use a new iron handle will begin to shift shadings, likely darkening more toward the pan body, with variegated effects emerging further out from the pan. Whatever fats get on your handle (including skin oils), repeated heating and cooling cycles continuously re-seasons, protecting the iron from corrosion and giving it its own character — strictly speaking not patination (since the crystalline structure remains relatively unchanged), but no less lively.
Living with Lively Cookware
Pure elements such as copper, tin and iron are extremely responsive to energy and contact. You might think of these cookware ingredients as “living metals”, born dramatically, developing refinement and grit with experience, improving in all their relationships — with each other and with you.
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