Unlike beer or wine, batches of moonshine have been known to cause blindness -- and there are multiple reasons why.
During distillation, a byproduct of alcohol forms. This byproduct, known as methanol, is concentrated in the first ounces of each round of moonshine. Scrupulous moonshiners discard these ounces, but if you happen to drink a bad batch, methanol directly affects the optic nerve and the body as a whole. It's a lightning-quick buzz, more effective than even the most potent alcohol, but just 10 milliliters (0.02 pint) of methanol can cause permanent blindness. Drink more than your body can metabolize, and it could kill you.
The scary truth is that some 'shiners have been known to sell methanol-tainted moonshine. In 2011, 168 people died in India after drinking methanol-laced alcohol. It all depends on the distillation process and the care of the person doling out the homemade hooch. Some have been known to trade copper tubing for truck radiators in the distillation process, which leach lead and glycol into the mix [source: Dillow].