Single barrel whiskey

Single barrel whiskey (or single cask whiskey) is a premium class of whiskey in which each bottle comes from an individual aging barrel, instead of coming from blending together the contents of various barrels to provide uniformity of color and taste.

By contrast, some other whiskeys, even ones that are not blends, may be combined from more than one batch, or even from differing years to achieve consistency.

Each barrel is believed to contribute unique characteristics to the finished whiskey.

Whiskeys sold by Scottish distilleries such as Ben Nevis and GlenDronach as "single casks" have been revealed to be vattings of multiple barrels, which may have been of different kinds, with the "single cask" designation referring only to the final cask for maturation.

[1] In the absence of specific regulation regarding this language, it is not clear to what extent this practice is prevalent in the industry as a whole.

Barrels of whiskey aging in a rick house. Most brands are a blend of multiple barrels, but whiskey may be bottled from a single barrel.
Bottle of Yoichi 10 Year Single Cask
A bottle of Jack Daniel's Silver Select Single Barrel Tennessee Whiskey