Copper is a far better metal for heat diffusers - because it is superior in thermal conductivity.
It works because copper conducts heat better than other metals - and your pans will heat more evenly!
Better cooking through modern material science!
Thermal conductivity data, @300 Deg. Kelvin (room temperature) in Watts/Meter-Degree Kelvin. (Science stuff)
Silver, Ag - 429 W/M-K
Copper, Cu - 401 W/M-K
Aluminum, Al - 237 W/M-K
Cast Iron, Fe - 80 W/M-K
Hi-Carbon Steel - 35 W/M-K
Stainless Steel - 15 W/M-K
Glass/Ceramic - 1 W/M-K
Copper is a superb conductor of heat, much better than other kitchen metals. Only silver is a better metal, but even silver is only about 7% better than copper.
Our Copper Heat Diffuser / Defroster Plates are made from C11000-High Conductivity Copper, 99.9% pure. This grade of Copper was developed for high conductivity, both electrical and thermal.
Also note that Gold comes in somewhere between Copper and Aluminum in thermal conductivity - It's just not that great of a heat conductor.
Relative metal mass and thermal capacity:
Copper is an excellent material for heat transfer, but can also hold more heat than ordinary cooking metals. This is called thermal mass. What this means is that a warm BellaCopper heat diffuser contains more heat than the same size aluminum or cast iron heat diffuser at the same temperature . More internal heat means no rapid cooling of the heat diffuser as it transfers heat to a cool pan. With the BellaCopper heat diffuser there are no transient hot or cold spots due to lack of thermal mass.
It's all about Entropy and Enthalpy (bet you never thought you would hear those words again after you got out of science class). Entropy is the property of heat transfer and conduction. Enthalpy is the property of how much heat something can hold. Copper is superb in both.
BellaCopper copper heat diffuser comparison to Aluminum:
The BellaCopper copper heat diffuser has 1.7 times the heat conduction of aluminum (70% better). This means the BellaCopper copper heat diffuser heats up almost twice as fast and far more evenly as the less efficient aluminum alternatives.
The BellaCopper copper heat diffuser has 3.3 times the mass of the same size aluminum heat diffuser. That means it will hold 3.3 times the heat. This insures your pans will come up to heat evenly and quickly. The low thermal mass of inferior aluminum heat diffusers means that cold spots and hot spots are inevitable, leading to possible damage to your delicate sauces and other fine foods
BellaCopper copper heat diffuser comparison to Cast Iron:
The BellaCopper copper heat diffuser has 5 times better heat transfer than iron pans and heat diffusers. The BellaCopper copper heat diffuser has 1.14 the density of Steel & Iron. This means better heat control (more thermal mass) and less cooling when a cool pan is put on the warm BellaCopper copper heat diffuser. Steel and Iron have a good thermal mass, almost as good as copper, but the poor heat conduction of iron allows hot and cold spots to develop while cooking.
BellaCopper copper heat diffuser heats up 5 times faster and far more evenly than inadequate iron and steel heat diffusers.
BellaCopper copper heat diffuser comparison to Stainless Steel:
The BellaCopper copper heat diffuser has 26 times better heat transfer than Stainless Steel pans, and has 1.14 the density of Stainless Steel. This means better heat control (more thermal mass) and less cooling when a cool pan is put on the BellaCopper copper heat diffuser. Steel has a good thermal mass, almost as good as Copper, but bad heat conduction of stainless steel allows hot and cold spots to develop while cooking. This is why good stainless pans have an aluminum bottom.
BellaCopper copper heat diffuser heats up 26 times faster and far more evenly than stainless steel pans. Using the BellaCopper copper heat diffuser will make the cooking surface of your stainless pans a more constant temperature from the center to the edge of the pan.