Rephrasing - When's the RATE of heat loss greatest, before or after COLD milk is added to HOT coffee?

Answer 1

Scientists at the Massachusetts Institute of Technology (MIT) did a scientific study on this years ago.

The rate of loss of heat from a liquid is a function of the starting temperature to the 4th power (T^4). So, if you want your coffee to stay warmer longer, add the milk immediately. It immediately reduces the initial temperature.

Answer 2

generally, the rate of heat loss depends on the difference in temperature between the hotter and colder sides of the barrier, - if the difference is greater, then the rate is greater, but I guess if you added a lot of milk the surface area might be much greater, so the loss might be increased from that point of view.... that is, you have a cup of hot coffee and it's losing heat to the air. OK, you add three cups of cold milk, the temperature of the coffee milk mixture is much lower so the rate of loss per suare inch of surface is less, but there are more square inches of interface.

If you are thinking about the rate of heat loss at the instant that you add the milk, that would be a high rate for a short time until the mixture equilibrated....

Answer 3

Upon adding the milk to the coffee