Brooklyn Copper Cookware specifies a special crystalline formulation of copper called C12200 phosphorus deoxidized, which is minimally 99.93% pure. The remaining .07% is mostly silver and phosphorus. Our copper is also RoHS (Restriction of Hazardous Substances) Directive compliant, i.e., effectively lead, cadmium and mercury-free. We keep these and other certifications updated and on file in case you’re interested.
No cookware material, not aluminum, not iron, not ceramic, and certainly not stainless steel, conducts heat like copper. Copper is 25 times more conductive than stainless steel, which can also be understood as copper cookware using 25 times less energy to move the thermometer up a degree. Those high-output (i.e., energy wasting) burners? They came along in response to the use of high-resistance stainless steel cookware.
“Copper is king here: It has nearly twice the thermal conductivity of aluminum… is five times more conductive than cast iron and 25 times more than stainless steel. Serious cooks love copper for this quality.”
– Nina Shen Rastogi, Slate.com
The first thing you’ll notice when using tin-lined copper cookware is how fast it heats up. You just don’t need a high-output burner when you use copper – the 3500°F at the tip of any propane or natural gas flame is plenty of heat. Whatever source of heat you use with copper cookware (except induction, which only works with ferrous metals), you can count on the energy going into the pot, rather than bouncing off the bottom and going up the outside while the metal figures out what to do with all those extra BTUs.
Stainless steel dominates the world of cookware, from pots and pans to knives. Certain of its working properties are justly appreciated, mostly that it’s stainless (read: mostly rust-free). In the case of knives the trade off for rustproofing is that stainless neither holds nor retakes an edge as readily as the other principle knife-making material, carbon steel. The purpose of a stainless knife – cutting – and how well it does that task is subordinated to how shiny it stays.
Stainless steel is a very hard metal, and in a knife that hardness resists taking and keeping a fine edge. That same hardness and resistance accounts for why the wires in your walls are not stainless steel – as tough and resilient as it may be, stainless is worthless for conducting electricity – too inflexible and resistant with a chaotic amalgam of metals with widely differing (and mostly low) electrical potentials. The wires in your walls are very likely made of copper, which conducts electricity with very little resistance. In fact, copper has the highest electrical potential of all the non-noble metals. We’re talking about cookware, however, and in cookware conduction is the name of the game.
Copper thick enough to get a fine, granular distribution of energy across the interior surface can also be so thick that it stores some of the heat energy; when, for example, you’re working with delicate sauces, this can be a real problem. An efficient metal sheds energy as quickly as it takes it on, so when you want your food off the heat, it’s off immediately.
This is why people have strong opinions about thickness and why most high-quality copper cookware is between 1.75 and 3mm. It’s thick enough to distribute energy uniformly, but not so thick that it stores too much of it, and what it takes in lightning fast it can get rid of just as fast. At about 3.25mm in thickness one begins to lose the fast heating advantages with no significant gains in distribution – the pot is just that much heavier and more expensive. The copper thickness of Brooklyn Copper Cookware is between 2.25 – 3.2mm depending upon the specific piece.
“Copper pots are the most satisfactory of all to cook in, as they hold and spread the heat well and their tin lining does not discolor food….. To get the full benefit of cooking in copper, the metal must be 1/8 inch thick, and the handle should be of heavy iron.”
-Julia Child, Mastering the Art of French Cooking, 1961
Note: 1/8 inch is equivalent to .125 (see above), or 3.2mm.