30-Year Old Scotch

A man walks into a bar and says to the bartender, "Give me a double shot of 30-year old scotch!"

The bartender thinks for a minute and decides to give the man 8-year old scotch. How could he know the difference?

He serves the man who drinks the scotch, spits it out and says, "This is 8-year old scotch--I ordered 30-year old scotch!"

The bartender apologizes, and figures, well, 20-year-old should be close enough.

He serves the man who again spits it out and yells, "I know scotch and this is only 20 years old! Now give me what I ordered or I'll take my business elsewhere."

The bartender then says "I'll get it from the back room, but that's amazing how you can tell the age like that".

Just then a drunk wanders over with a glass and tells the man "Try this!"

The man drinks it, spits it out and says, "This tastes like piss!"

The drunk says, "Yeah, but how old am I?"