As a homebrewer there is always the danger of Methanol being produced instead of ethanol. How do i test for this? Drinking my homebrew, certain batches make me feel really tired, is this a symptom of methanol poisoning?

No, its a symptom of getting drunk!!!

you`ll get many different types of alc in homebrew, not usualy in quantities to do any real harm though, it`s during distilation that problems can occur.

there are also different levels of congeners in any brew, depending on what type of mash you`re making, these can leave you feeling a little Ill too.

Generally speaking, the major side effect of methanol poisoning is going blind. Not really too nice of a side effect.

Methanol and ethanol are really similar, smells and taste the same. You don't need much methanol to make You're world spin /I've checked that on myself, oh my sacrifice in the name of science.../ Books always says it's impossible to say where is methanol and where ethanol without a lab full of funky stuff, but that's a lie. There's an easy way to check that, I don’t remember exactly how, but when using sth. with Iodium methanol change color to yellow

I can tell the difference based upon the smells. Methanol has a much 'sweeter' smell to it than ethanol does. Ethanol has a bit more 'alcohol-like' odor to it while methanol tends to have a sugary sweet odor. Methanol is also incredibly toxic, but that's not something you can just tell by the odor or looks. Approximately 2 shot-glasses full of methanol will kill a typical adult, while far less than that will make them violently ill and/or blind. Oddly enough, the best antidote to methanol poisoning is ethanol. If someone is admitted to the ER after ingesting something with methanol in it, they will give them straight ethanol instead. The body would rather metabolise ethanol than it would methanol, so the methanol winds up being filtered out of the system unaltered. Methanol itself is not poisonous to human beings, its the metabolite of it that is deadly. Methanol is metabolised by the body into formaldehyde which does the major damage. Unaltered methanol will just pass right through your body and is quickly excreted. Hence why they treat methanol poisoning with ethanol. The alcohol dehydrogenase enzyme is better suited to attacking ethanol than methanol, so if there's a bunch of ethanol in the system it will 'ignore' the methanol which is promptly excreted in the urine. This is the reason why the small bit of methanol which exists in all alcoholic beverages is nothing to worry about. The proportion of methanol to ethanol is far to small to cause any harm.