Whether you plan to enjoy the race from Churchill Downs or don an elaborate hat in the comfort of your own home, if you're watching the Kentucky Derby, you may find yourself sipping on a refreshing mint julep this weekend. But, why?

The drink—a cocktail traditionally composed of bourbon, sugar, water, and mint—has been a Kentucky favorite since long before Churchill Downs came into play. In fact, in 1816, silver julep cups were given as prizes at Kentucky county fairs (a change from the stuffed animals they offer today). And before that, a “julep” was considered medicinal, “prescribed” for stomach problems and sore throats.

Though mint juleps have likely been enjoyed at the Kentucky Derby since the beginning—legend has it that founder Meriwether Lewis Clark, Jr., planted mint for cocktails when he founded the track in 1875—the cocktail wasn’t declared the “official” Derby drink until 1938.

Just last year, the Derby switched to a more “authentic” version of the mint julep. For almost two decades, the 120,000 mint juleps served at the races were made with Early Times. Based on the aging process, Early Times isn’t considered bourbon (just “Kentucky whisky”) in the U.S. In 2015, they switched to Old Forester, which is also owned by the Brown-Forman Corporation.

Even with the switch to “real” bourbon, what most revelers actually get is the Old Forester Ready-to-Serve Cocktail mix, not a handcrafted mint julep—unless you’re willing to pony up $1000. For the past decade Brown-Forman has served a special version of the drink made with Woodford Reserve small batch bourbon. It’ll set you back a grand, but hey, you get to keep the pewter cup—and proceeds go to benefit the Wounded Warrior Equestrian Program.

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