There is no formal definition of ‘single estate’ spirits, but it is widely understood that producers source the vast majority of ingredients, or at least the primary ingredient, for their product from one specific area of land (much like you would expect single estate coffee to be).
Typically the distillery in question also owns this area of land and/or played a role in overseeing the growth and harvesting of the produce, but it’s not always the case.
For example, a Cognac created from eau-de-vie that’s been grown on a single vineyard is sometimes described as single estate, because it is different to the usual practice of blending eaux-de-vie made from grapes sourced from various different estates and/or regions.
Rum pushes the concept a little more loosely, where Molasses rums can be deemed as ‘single estate’ if the producers own sugar factories and therefore use their own molasses in their production process, (even if they may not own all the cane fields the starting ingredient comes from or that the cane was grown at multiple farms). Make of that what you will…
Single Estate is different from Farm to Bottle, as it’s less about a from scratch production process and more about the terroir of the raw material itself.