Then he [Jesus] called the bridegroom aside and said, “Everyone brings out the choice wine first and then the cheaper wine after the guests have had too much to drink; but you have saved the best till now.”

This, the first of his miraculous signs, Jesus performed in Cana of Galilee. He thus revealed his glory, and his disciples put their faith in him.

(from John 2:1-11)

I know that this passage probably has some deeper meaning, but I found a sermon online, which summed up this passage thus: “Jesus even seemed reluctant to get involved in the impending social faux pas that was about to occur until his Jewish mother prodded him and said “Jesus, my son, they have no wine.”

All I have to add is that figuring out the correct amount to alcohol to buy for your wedding has clearly always been a problem, even in ancient times.