What does Barrel Proof mean?

What does Barrel Proof mean?

The term ‘Barrel Proof’ or ‘Cask Strength’ can be a little misleading in some instances. The term refers to the strength of the whiskey, measured in ABV% or PROOF. Most whiskey is cut with water to reduce its strength, to make it more palatable and also to increase the yield.

The strength of the alcohol varies from barrel to barrel based on entry proof, weather, warehouse placement and number of years the liquid stays in the barrel. Strength variation is further influenced by how much of the distilled spirit evaporates through the barrel during the ageing process. If more alcohol evaporates proof will reduce, if more water evaporates proof will increase.

• "Barrel Proof' or ‘Cask Strength’ is used by some producers to describe a whiskey that has not been 'substantially' diluted when bottled. 
• In other instances and when the bottle states that the whiskey is 'undiluted' or 'uncut', Barrel Proof / Cask Strength means the whiskey is bottled at the same strength as it left the barrel / cask.

The terms are used for both ‘single barrel’ and ‘small batch’ whiskey.