Molotov question.

A recent conversation brought to mind a poster a friend of mine has that says something along the lines of, "the only thing worse than a zombie trying to eat your brains is a zombie trying to eat your brains while on fire" suggesting that the use of fire as a weapon may be unadvisable.

However it occurred to me that, given you're not within immediate chasing distance, fire may be a good way to clear a large crowd.

Am I incorrect in thinking that the brain of a zombie will, essentially, rupture on a cellular level when heated like that and you therefore don't need to wait for them to burn completely?