Why do I always burn my mouth when eating potatoes? Why do they stay so hot?
Dear Ms. Tater,
It is true that, long after the asparagus has gone cold, your baked potato will be deliciously, or perhaps dangerously warm. The reason behind this is the high heat capacity of a potato.
Technically speaking, heat capacity (or “specific heat”) is how much heat is needed to change the temperature of a substance by one degree. This specific measurement lets you compare the heat capacity of different things on an even scale. Potatoes, above freezing, weigh in at 3.43 kilojoules of energy to raise 1 kilogram of potatoes one degree centigrade.
However, asparagus has a specific heat of 3.94, meaning it holds heat better than a potato. So, what now?
Well that is a measure of the amount of heat held per a specific weight of the vegetable in question. Potatoes trump asparagus in the density department. With more than twice as much density, an equal serving of potatoes and asparagus would have the potatoes staying warm twice as long.
Another important part of your supper’s ability to retain heat is conductivity and surface area. The heat from your food gets transferred to the cooler air around it, and the more it is in contact with the air, the faster this transfer can take place. For this reason long skinny french fries will cool much faster than a solidly round baked potato. (a sphere is the best shape for minimal surface area to maximum volume)
So when your asparagus comes out of the oven at the same time as your potatoes, start with the greens to save yourself from a burning mouth.