Going by the barbed wire you'd think that these casks might actually be full of whisky, and that the coating of frost was part of the secret alchemy that turns barley, water and yeast into the water of life. They're certainly precious enough - many are old sherry casks from Spain, or Bourbon casks from the USA - but they're all empty, and stored in these pyramids until they're needed.
Each cask is stamped with the name of the distillery, or group of distilleries - in this case the Highland Distillers - a serial number, and the year in which the cask was filled. I think I can make out 1994 on one, and possibly 1988 on another. Their turn will come round again.