Chemistry - How to test for methanol?
For more information, read the Wikipedia page having Azeotrope tables.
There's probably no reliable chemical test for the presence of methanol in alcohol mixtures that could be carried out at home without decent laboratory equipment.
Qualitative tests such as esterification with boric acid and subsequent flame test or oxidation to formaldehyde and its detection are unreliable, especially in the presence of ethanol. I advise against using such tests to decide about the presence of methanol in distilled liquors.