Upvote:3
Here are a few points I got from a book on the Ancient Indus, by Rita P. Wright.
Archaeologically, you can look for burnt stones. Here for example is a mention from a site from around 25K BP: http://prfdec.natur.cuni.cz/~kfggsekr/rggg/pdf/Svoboda_etal_09.pdf
Upvote:8
I can't speak to boiling in particular, but if it's just evidence you're asking about, there's evidence of Homo Erectus (a human ancestor) using controlled fires about a million years ago.
Archeologists are actually involved in a raging debate about human cooking right now. The oldest faction argues based on artifacts and skeletal features like dentition that it was an innate behavior of Homo Erectus, which would make it about 1.8 million years old. The youngest faction argues that man certainly "harvested" wildfires when available, but didn't master the ability to create fires at will until only about 12,000 years ago (which would make it a part of the Neolithic Revolution).