Paul John (whisky) evaporation during aging, known as the angels' share, is also higher in India, at 10–12% per year, than in Scotland, where the annual evaporative loss is about 2%. This leaves a hogshead with only 150 bottles left in it, after three years, compared to around 350 in a Scotland. Michael John describes it this way, "Whisky matured at these temperatures simply cannot be aged for the kind of time expected with Scotch, even trying to mature our whisky for just 10 years would leave barely a bottle of liquid in the barrel. Fortunately, the heat actually speeds up the maturation
Barrel the much lower cost. Sherry is stored in casks made of North American oak, which is slightly more porous than French or Spanish oak. The casks, or butts, are filled five-sixths full, leaving "the space of two fists" empty at the top to allow flor to develop on top of the wine. Sherry is also commonly swapped between barrels of different ages, a process that is known as Solera. Laws in several jurisdictions require that whisky be aged in wooden barrels. The law in the United States requires that "straight whisky" (with the exception of corn whisky) must be stored