@G8GDS - Yes, it is possible that methanol was deliberately added. It's also possible that a distiller used pomace, skins, peels: fruit by-products which are high in pectin, which converts to methanol and requires additional attention to the "cuts", the portion that you discard from the still. These are popular with moonshiners because as a waste product, they are cheap or free. A skilled distiller can make grappa from them, an unskilled one can kill someone.