Casks come in all shapes and sizes. After distillation, a cask is usually “topped off” with new make spirit. Over time, the bulk volume will gradually decrease due to evaporation of the liquid through the pores of the wood. This is called “Angels’ Share” and the Scotch whisky industry has set this loss figure at an average of 2% annually. In general: the older the whisky, the less liquid will be left in the cask.
