Brenne is a single malt whisky produced with copper alembic stills as opposed to copper pot stills. It ages first in new Limousin oak barrels, used typically to age brandy, before finishing in ex-Cognac casks. They are bottled in batches and never blend the barrels together. Each bottle is numbered with the barrel number from whence it came. Bottle variation will occur, but on average the whisky is 7 years old.