Cookware Color and Heat Transfer

[Shel_B]

The other day I cooked up some corned beef in a black Le Creuset Dutch oven. In the past I've uses a white one, about the same size. It seems that the black LC would have the water boiling at an oven setting less than the white pot. In fact, I had to turn the oven down twice to maintain a simmer.

So, will a black pot absorb more heat in an oven, and, by extension, transfer that heat to the food and the cooking liquid?

Thanks!

[dougal]

Good observation!

Black should certainly heat up faster - because it better absorbs whatever radiant heat is on offer.

As almost all cooking is done under non-equilibrium conditions, black will be 'faster'.

But long slow simmering is as close as you'll get to an equilibrium situation outside sous vide.

The rate of bubbling you see while simmering a braise is a function of the rate of heat input to the stew.

Its actually a measure of that input energy.

The total heat energy input to the pan is from the combination of radiation, conduction and convection.

As you have noted, to get the same energy input to the stew, you need to set the oven at a lower heat output (a lower temperature setting), because the energy transfer to the black pan is more efficient, which is because the black one is capturing more of the radiant component of the energy.

A big question question though is how much of the heat is radiant. And that will differ for different oven designs.

You normally encounter the "black is better" phenomenon with bakeware.

A black bread tin will indeed give a better-risen loaf than a shiny new one! (Even when all other factors are identical.)

However, I suspect that Rose Levy Berenbaum, (who teaches the insulation of cake tin sides to get a flatter top), might therefore advise that shiny was better than black for the specific task of cake-baking ...

The difference between black and white casseroles is rather like the difference between using natural and fan-forced convection in the oven. The fan increases the rate at which energy is transferred by convection at the same temperature - hence the cooking advice to turn the temperature a little lower when using the fan, and thereby maintain the same traditional rate of energy transfer to the food.

[paulraphael]

You normally encounter the "black is better" phenomenon with bakeware.

A black bread tin will indeed give a better-risen loaf than a shiny new one! (Even when all other factors are identical.)

However, I suspect that Rose Levy Berenbaum, (who teaches the insulation of cake tin sides to get a flatter top), might therefore advise that shiny was better than black for the specific task of cake-baking ...

This is because the goal in baking is generally not to have the most radiant heat absorption possible, but the amount that gives a similar level of browning on the parts of the food in contact with the pan and the parts in contact with the air.

Dark colored pans will brown faster than the air; you'll have bread or cakes that are darker on the sides and bottom than on the top. Brightly polished metal will brown more slowly than the air; you'll see the opposite result. Light but unpolished metal (which describes most professional bakeware) generally comes closest to even browning.

Insulating the sides of cake pans is for the purpose of a flatter top, as you suggested. It will also give you less browning on the sides, but presumeably no one cares much, if the cake will be frosted.

I've found dark (black steel) pans to give the best results with tarts; in this case crisping the bottom without overcooking the top can be a challenge.