Expositor's Bible Commentary Commentary John 2:9

"And when the ruler of the feast tasted the water now become wine, and knew not whence it was (but the servants that had drawn the water knew), the ruler of the feast calleth the bridegroom," — John 2:9 (ASV)

The “master of the banquet” was not the host, but a headwaiter or toastmaster called in to take care of the distribution of food and drink at a large social occasion. He was astounded by the high quality of the wine, since generally a poorer quality was served once the taste of the guests became dulled.