Cooling a hot drink by blowing on it?
In Shariah, eating or drinking hot things is not preferred, and it is also severely harmful from a medical perspective; therefore, hot things should be consumed only after they have cooled down a little. And if one blows from the mouth to cool it, saliva, etc., might get mixed in, creating an unpleasant situation. Therefore, the Holy Prophet (Peace be upon him) has forbidden cooling food and drinks by blowing on them. (Kitab al-Nawazil / Vol: 16 / Page: 129)