Chill Filtering
Chill filtering is a method in whisky making for removing residue. In chill filtering, whisky is cooled to between -10° and 4° Celsius (often roughly 0°) and passed through a fine adsorption filter. This is done mostly for cosmetic reasons – to remove cloudiness, rather than to improve taste or consistency.
Method
Chill filtering prevents the whisky from becoming hazy when in the bottle, when served, when chilled, or when water or ice is added, as well as precluding sedimentation from occurring in the bottles.
Chill filtering works by reducing the temperature sufficiently that some fatty acids, proteins and some esters precipitate out so that they are caught on the filter. Single malt whiskeys are usually chilled down to 0°C, while the temperature for blended whiskey tends to be lower since they have lower levels of fatty acid.