The name describes a fermentation method rather than a flavour. In the sour mash process a portion of a previous fermentation is held back and used to start the next one — the same principle as a sourdough starter — which stabilises acidity and keeps character consistent from batch to batch. Nearly all Kentucky whiskey is made this way; Michter's is unusual in putting the term on the label, because the name traces to its own Original Sour Mash Whiskey. What separates this whiskey from its neighbours is the grain bill, which Michter's does not publish beyond saying that its selection means the result cannot be categorised as either a rye or a bourbon; the distillery has described a fair proportion of rye alongside corn and malted barley, and reviewers have inferred that corn sits below the 51% threshold US rules require for bourbon. The whiskey is distilled and bottled in Kentucky, matured in fire-charred new American white oak, batched in small quantities, and bottled at 86 proof. No US★1 whiskey is released until Master Distiller Dan McKee and the Michter's tasting panel judge it ready.

Every bottle sold through Midnight Whiskey is sourced as an authentic, sealed product and inspected before it ships. Orders are packed with padded, glass-rated handling and require an adult signature (21+) on delivery; we do not ship to anyone unable to verify legal drinking age. For our full sourcing and handling protocols, see our editorial and authentication standards.

Why is Michter's Sour Mash not called a bourbon?

Because of its grain recipe. Michter's states that the grain selection behind this whiskey means it cannot be categorized as a rye or a bourbon, and the distillery has described the mash as carrying a substantial share of rye alongside corn and malted barley. Reviewers reading that have concluded the corn content likely falls below the 51% minimum US rules require for bourbon, which is why the label simply reads whiskey. Michter's own shorthand for the result is that it starts out like a bourbon and finishes like a rye.

What proof is Michter's US*1 Small Batch Sour Mash?

86 proof, or 43% alcohol by volume — a fixed strength that every bottle carries. It is bottled in small batches rather than drawn from a single barrel, and unlike Michter's barrel-strength releases, whose alcohol level varies from barrel to barrel, this one is proofed to a consistent figure.

What does sour mash mean?

It is a fermentation method rather than a flavour. A portion of a previous fermentation is held back and used to start the next one, much the way a sourdough starter works, which keeps acidity and character consistent from batch to batch. Most Kentucky whiskey is made this way; what is unusual here is the name on the label, which traces back to the Original Sour Mash Whiskey that was Michter's best-selling product in the 1970s and 1980s.