You can test for methanol in various ways during destillation. But also you don’t need to test for it, if you control your temperature properly and discard a sufficient amount at the beginning.

Even if you would not discard anything, if you fill all your destillate in one container, so ethanol and methanol mix again, it decreases the effectiveness of the methanol.

Methanol itself is not directly toxic. The damage is done by formaldehyde and formic acid that come from your body metabolising the methanol. Methanol gets metabolized on the same routes as ethanol, which the body favors. So one way to treat methanol poisoning is by ingesting untainted ethanol.

https://en.wikipedia.org/wiki/Methanol_poisoning

All fermented drinks contain both ethanol and methanol. But because the ratio is not altered with bad distillation, you wont get methanol poisoning from untainted beer or wine.

The only quick and easy way I know is to burn it in a dark room. If you get a pure blue flame you’re good. But if it’s at all orange, it needs another go through the still.

Do you realise how fucking regulated alcohol making and indeed, any sort of food or beverage making is in Europe? This sort of shit only happens in countries where you have a deadly mixture of ignorance, poverty and corruption.

Farmers in rural France know you throw away the first part of the moonshine because it’s the part that makes you go blind, for example. And it’s precisely to prevent any sort of accidental mishaps they ended up forbidding the making of it anyway (it used to be allowed for cattle farmers, iirc). Although I believe they rolled back that one, what with the explosion of microbreweriea and such. Also if it’s legal can tax it.

Before the Russians went full stupid, they would bring illegal booze across the border into Poland and most of it should have been poured into a fuel tank.