Avodah Zarah 30 - Cooked Wine and Wine Left Uncovered
The Sages prohibited the consumption of wine, water, or milk that was left uncovered, for fear that a snake may have drunk from the liquid and cast its venom into it. The prohibition is based on the requirement to take great care of one's health and well-being. Today, when snakes are not prevalent, the prohibition does not apply, though some say that it has additional mystical connotations. In any case, it does not apply to cooked wine, because a snake would never drink such wine.
Art: The Winetaster by Heinrich Stelzner
