What is single barrel whisk(e)y? "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. Even whiskeys that are not blends may be combined from more than one batch, or even from differing years to achieve consistency. The whiskey from each barrel is bottled separately, with each bottle bearing the barrel number and in most cases the dates for the beginning and end of aging. Each barrel is believed to contribute unique characteristics to the finished whiskey." Source: Wikipedia. In short, single barrel whisk(e)y are bottles that come from one unique barrel, instead of from a blend of various casks. Single barrel whisk(e)y making is done in both North America and Scotland, and the producers aim to create an (ultra) premium whisk(e)y class.

Single barrel whisky ...

Wanna make a unique style even more unique? The iStill 2000 allows you to do your whole production process in one single batch. You can use the unit to mash, and help convert starches to fermentable sugars. You can then start the fermentation, in order to create alcohol and flavors. And when fermentation is done, just upload the relevant program and distill your wash into an amazing whisky. The iStill 2000 can help you migrate from a single barrel approach to a single mashed, single fermented, and single distilled whisky. Unique and special and versatile, even before barrel aging begins! One exact mash ... leads to one totally controlled ferment ... leads to one specific distillation run ... leads to one totally unique barrel!

Yield: a unique barrel of single mashed, fermented, and distilled whisky per run ...

https://istillblog.com/2016/05/22/revolutionizing-craft-distilling-once-more/