This is handy

[Gymrat]

[Beer-lord]

In the old days when I was in high school (but we did have A/C back then) we did this in science class. We always said we'd try this on our fathers' beer (because we didn't drink in high school) but we always forgot about it.
It does really work.

[mashani]

Same principle as making ice cream the old fashioned way. Except less churning LOL.