Wine is blessed on the Feast of St. John in remembrance of the legend that St. John safely drank poisoned wine offered to him by his enemy after blessing it. In Rome we carried our bottles of wine to church in a basket on this day for the blessing after Holy Mass.
Source: Roman Ritual
P: Our help is in the name of the Lord.
All: Who made heaven and earth.
P: The Lord be with you.
All: May He also be with you.
Let us pray.
Lord, Jesus Christ, Son of the living God, who in Cana of Galilee changed water into wine, be pleased to bless + and to hallow + this creature, wine, which you have given as refreshment for your
servants. And grant that whenever it is taken as drink or poured into
wounds it will be accompanied by an outpouring of grace from on high.
It is sprinkled with holy water.