An exclamation of joy or description of great quality.
On International Beer Day the word "Beertastic" may be substituted for virtually any positive adjective.
"This meal is positively Beertastic!"
Guy 1: "Dude, it's raining beer outside!"
Guy 2: "Beertastic!"
Refers to the moment in which you realize that a specific alcoholic beverage, most likely beer, is insanely pleasing thus you must continue to drink. However Beertastic can be used simply to describe a moment in which you must drink, have drank, or when you simply want to display pleasure with a certain action non-alcoholic related!
Holy shit, that chick is beertastic.
OMG that was the most beertastic moment I have ever had at a bar!