In 1933, winning Indy 500 driver Louis Meyer requested a bottle of buttermilk (his favorite beverage) to refresh himself after winning his second race at Indy.
Three years passed before Meyer won the title again. Again he asked for the milk. But this time, a local newspaper snapped a pic and the sensation took off.
Every year since Meyer's picture, the Indy 500 winner has downed a bottle of milk.
The difference between then and now? There are three bottles of regular milk (not buttermilk) kept in a chilled refrigerator trackside. The winning driver has his choice of either whole, 2 percent or skim. Oh yeah, and etched in the bottle, an even better tradition drivers love, "Indianapolis 500 winner."
And now the mystery is solved! A nice, tall glass of milk after 500 grueling miles in a very hot car is just what each of these drivers wants. That, and win the most coveted race in the IRL.