Ever noticed how certain foods seem to get a lot hotter than others? I almost never burn my tongue or mouth… except on tomatoes; Pizza sauce, tomatoes in panini sandwiches or spaghetti sauce.
Tomatoes always seem to get hotter and retain their heat longer than almost any other food I've encountered. And they are nearly always the culprit when I succeed in burning my mouth.
Why would that be? Is there something about their chemistry that causes them to have a higher heat capacity? Do they hold their heat longer? Or is it simply a figment of my imagination and bad luck with hot tomatoes?
Best Answer
Another physics digression.
All cooked food gets hot, and everything in any given dish will have the same temperature {*}. The tomatoes don't get hotter than the other ingredients. But they do have a tendency to burn more than certain other substances, so the question is "Why?".
You get burned when a portion of your flesh reaches a high enough temperature{+}. The food warms your tongue, lips, etc. by heat conduction until either you move the food or your mouth parts and the food reach the same temperature (a condition known as thermal equilibrium). What that common temperature is depends on the amount of heat (i.e. thermal energy) in the system. Some of the factors that come into play are:
How fast the common temperature is reached depends on
Some consequences of all this:
{*} Well, sort of. But take that as true for any particular region of any particular dish.
{+} What temperature is that? Good question. Maybe there is a medical professional around, 'cause I don't know. I'd guess around 140--150 degrees F (call it 60--65 degrees C), but don't quote me.