Hot liquid on Shabbat

Hi,

We generally rule that one may not heat liquids on Shabbat above approximately 113 degrees (Fahrenheit), even if they have been heated to that level before. There is a leniency, though, for liquids which have not cooled off entirely.

According to Rav Moshe Feinstein, the standard for "not cooled off entirely" is that people who want to drink a hot drink would consider this hot enough for their purposes.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 4:74:Bishul 2)

Have a great day,
Mordechai