Chill filtration
Many whiskies are bottled after being “chill-filtered”. This is a process in which the whisky is chilled to near 0°C (32°F) and passed through a fine filter. This removes some of the compounds produced during distillation or extracted from the wood of the cask, and prevents the whisky from becoming hazy when chilled, or when water or ice is added.
Chill filtration also removes some of the flavour and body from the whisky, which is why some consider chill-filtered whiskies to be inferior.
