Weird taste and smell after heating

So I'm making high ABV alcohol with just plain sugarwash, high alcohol yeast and freeze distilling. I added chitosan and kieselsol(turbo cleaner) to clear it before freeze distilling but my yeast was still live so it did nothing. I then heat up the liquid to 65 degrees to kill the yeast and maybe evaporate any weird things. Something smells and tastes really off, while before it was drinkable and actually pretty pleasant, even though it was just fermented sugar wash. I'm curious as to why the heating might have caused this and if it's still salvageable by normal distilling. I might give up on freeze distilling and just get a normal still.