By Rabbi Doniel Neustadt
For final rulings, consult your Rav
QUESTION: If one wants to cool off boiling hot tea or soup on Shabbos, may he put an ice cube into the cup or bowl?
DISCUSSION: If the tea cup or the soup bowl is a keli shelishi, as is most often the case, then it is permitted according to all views to put an ice cube in it. If, however, the cup or bowl is only a keli sheini and the tea or soup is piping hot, putting ice in may be a possible issur min ha-Torah and should be avoided