Michter's US★1 Original Sour Mash Whiskey is a small-batch American whiskey distilled and bottled in Kentucky. With a unique grain selection that cannot be categorized as either rye or bourbon, it represents a truly distinctive expression in the American whiskey tradition. Originally Michter's most popular product throughout the 1970s and 1980s, it disappeared from the market in 1989 before making a triumphant return in 2012 as part of the US★1 line — named to honor Michter's heritage as America's first whiskey company.

The "sour mash" process draws its name from the fermentation technique in which a portion of previously fermented mash is used to start a new fermentation batch, similar in principle to sourdough bread making. This method ensures consistency across each small-batch bottling. Michter's current Sour Mash recipe was inspired by a historic formula of approximately 50% rye, 38% corn, and 12% barley, but reimagined with the intention of improving upon it.

Bottled at 86 proof (43% ABV), the whiskey is aged in fire-charred, new American white oak barrels in a heat-cycled warehouse, which causes the wood to expand and contract with temperature changes, mingling deeply with the spirit. The nose delivers warm toasted burnt sugar with spice, while the palate offers candied cherries, honeyed vanilla, dried fruits, and herbal tea with a hint of roasted nuts. It opens like a bourbon and finishes like a rye, with a long, slightly bitter close of pine needles, roasted coffee, and oak.

Michter's US★1 Sour Mash Whiskey was named "Whisky of the Year" for 2019 by The Whisky Exchange, becoming the first whiskey made in the United States to ever receive this honor. Each bottle is part of a limited, small-batch release overseen by Master Distiller Dan McKee and the Michter's tasting panel.