Clay pots, birch bark pots, skin lined pits et al all using hot rocks perhaps but I doubt hot water was high on the agenda. I suspect if you could not eat food raw or cook using a fire (over, under, embers, rocks etc) you'd not eat it. I doubt there is anymore evidence to show our very distant ancestors sat down to a cup of pine needle tea than there is that they used friction fire lighting (in the UK), both of which are slim options in the real world of basic everyday survival.
Ye Oldie bushcraft must have been grim times to live to say the least.