In the distilling process, methanol has a lower Vaporization temperature than ethanol and thus is the first thing (heads) out of the still along with some other nasties. Good distillers carefully monitor the temperature and composition of the distillate. The goal is to separate the heads from the more desirable ethanol. the heads are discarded or used for windshield wiper fluid. Distillers that fail to do this deliver their customers a product that can blind and kill.
Good explanation. Thank you.