Why would a pan of oil start "boiling" AFTER only the bottom was cooled?

Question

I was trying to sautee some stuff in oil, when I noticed the oil the food was starting to brown more than I wanted, I ran water in my sink, and put the bottom of the pan in the little water that didn't go down the drain. The oil, which was not boiling previously, started to boil, and I could see minuscule air bubbles rising from the pan.

Thanks.

Answer 1

You are right

When the bottom of the pan cooled suddenly due to the water in the sink, it created a very sharp temperature gradient (high change of temperature from one layer to the next layer of oil)

As you know boiling is a "convection" in which a liquid goes into a swirly circulation due to differing temperatures of various layers causing differing densities.

But in convection warmer layers from the bottom move up due to reduced density - but we seem to have the opposite situation here

Perhaps the oil at the edge of the surface got cooled and started sinking and displacing the rest of the hot oil...?

Or perhaps...its like the other answers: you might have got some moisture into the oil

Answer 2

oil doesnt boil, at least not at temps you can provid in your kitchen, you need to get it up in the 1,000 degree mark. for it to boil it must be evaporating, which we all know doesnt happen with oil, thats why its used in lotions, because it doesnt evap and locks in other liquids like water.

you probably got some water (maybe even a mist) in the pan. the oil was hot enough to heat the water to a boil.

Answer 3

You probably got water in the pan with the oil. the boiling of the Oil was actually the water violently boiling away.

FYI this is a dangerous situation and the cause of many kitchen burns. The boiling water can cause oil to splatter on your skin and cause a bad burn.

If you have a pan of oil that is too hot, remove it form the heat. I have also found that adding some fresh oil from the bottle at room temperature will help cool down the whole mess very quickly.