Phase Diagram of Cheese?

Most recent answer: 10/22/2007

Q:
At room temperature, cheese is usually a solid. If you heat it up, it is a liquid. If you heat it up even more, does it turn into a gas? If so, at what temperature?
- Nick (age 22)
University of Illinois, Champaign, IL, USA
A:
Cheese is a complicated suspension of many different substances. There’s water, there are oils and fats of various kinds, calcium compounds, and all sorts of important nutrients that calves need in their mother’s milk. In addition, there are bacterial cultures which are responsible for the fermenting of the cheese, and maybe some mold too.

I wouldn’t expect the cheese to have just one melting or boiling temperature. It’ll probably get soft and gooey as the temperature goes up, and how gooey it gets at what temperature probably depends quite a lot on the kind of cheese and its own history. For example, cheese that’s been left in my refrigerator unwrapped for too long will be dry and brittle (sliced cheese in particular!). This cheese may not get soft and gooey when cooked on top of a pizza, but may stay hard until it burns. Your cheese may burn before turning into a gas.

Some cheeses will bubble if you cook them in a pot on a stove. This probably is the water boiling off. The oils will go at a much higher temperature (they may give off something that looks like smoke instead). The solids might burn before melting or boiling.

Tom

(published on 10/22/2007)

Follow-Up #1: extremely hot cheese

Q:
Eventually if you heat up your cheese (or whatever remains of it) to several thousands of degrees, the organic compounds will break up and you will end up with a very hot plasma. If you heat up this plasma in an small enclosed space to several millions of degrees, the hydrogen atoms will start nuclear fusion and you will have made some nuclear cheese (at least for few microseconds).
- Anonymous
A:
Thanks for the cooking tips.

Mike W.

(published on 04/09/2011)