The boiling point for ethanol and methanol are close and methanol boils at a lower temperature, so if you distill your alcohol incorrectly, your end product cou

The boiling point for ethanol and methanol are close and methanol boils at a lower temperature, so if you distill your alcohol incorrectly, your end product could have both ethanol and methanol. Unless you test for it, you won't know that you have both which is why illegally made alcohol would cause blindness, hence the turn "drinking yourself blind".