Source: Pota Phádraig or Patrick’s Pot
Ordain a Statute to be Drunk
And burn Tobacco free as Spunk
And fat shall never be forgot
In Usquebah, St Patrick’s Pot
The custom of imbibing alcohol on St Patrick’s Day comes from an old Irish legend. As the story goes, St Patrick was served a measure of whiskey that was considerably less than full. St Patrick took this as an opportunity to teach a lesson of generosity to the innkeeper. He told the innkeeper that in his cellar resided a monstrous devil who fed on the dishonesty of the innkeeper. In order to banish the devil, the man must change his ways. When St Patrick returned to the Inn some time later, he found the owner generously filling the patrons’ glasses to overflowing. He returned to the cellar with the innkeeper and found the devil emaciated from the landlord’s generosity, and promptly banished the demon, proclaiming thereafter everyone should have a drop of the “hard stuff” on his feast day.
This custom has come to be known as Pota Phádraig or Patrick’s Pot. The custom is called drowning the shamrock because it is customary to float a leaf of the plant in the whiskey before taking a shot.