It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) forbade blowing into a drink.
Hadith Referenceسنن دارمي / من كتاب الاشربة / 2171
Hadith Takhrijاس روایت کی سند صحیح ہے۔ دیکھئے: [أبوداؤد 3728] ، [ترمذي 1888] ، [ابن ماجه 3428] ، [أبويعلی 2402] ، [ابن حبان 5316] ، [الحميدي 535] ، [بغوي فى شرح السنة 3035]
Brief Explanation
(Commentary on Ahadith 2169 to 2171)
In these ahadith, there is an instruction to refrain from blowing into water or any other drinkable thing. Lest something from the mouth falls and contaminates the water, causing harm or aversion and dislike to others. And Allah knows best.