Abu Sa'id Al-Khudri (May Allah be pleased with him) reported:
Messenger of Allah ﷺ prohibited us blowing in the drinking water. A man said: "O Messenger of Allah! Sometimes I see some litter floating about on the surface. What should I do then?" He ﷺ replied, "Pour them out." Then the man said: "My thirst is not quenched with one draught." Messenger of Allah ﷺ said, "Then put away the cup from your mouth (in between three gulps), and take breath."

[At-Tirmidhi].

عن أبى سعيد الخدرى رضى الله عنه أن النبي ﷺ نهى عن النفخ في الشراب، فقال رجل : القذاة أراها في الإناء؟ فقالب: "أهرقها" قال: إني لا أروى من نفس واحد؟ قال: "فأبن القدح إذاً عن فيك" .