What is chill filtration and how does it affect my choice of single malt? The purpose of chill filtering is to remove naturally occurring fatty acids, proteins and esters that are first formed by enzyme reaction of yeast and alcohol during fermentation. This is to eliminate the cloudiness these elements create when the whisky is cooled. The main reason to chill filter a whisky is purely cosmetic.
A non-filtered whisky that is 46% ABV (alcohol by volume) orlowerwill go cloudy when ice is added. However, whiskies with an ABV above46% do not require chill filtration, as the higher alcohol level prevents this cloudiness from occurring.
Fatty acids, esters and proteins occur naturally during the distillation process. When the whisky is cooled, these fatty acids, esters and proteins clump together to give the cloudy effect. A whisky that is not chill filtered is also likely to develop sediment in the bottle if stored in a cool place. The assumption is that cloudiness and sediment have been frowned upon by the consuming public. So early in the 20th century, distillers figured out how these elements could be removed.
Chill filtration involves dropping the temperature of the whisky to zero degrees Celsius for single malts (and lower for blends). Once chilled, the whisky is passed under pressure through a series of tightly knit metallic meshes or paper filters. The filtering process is designed to also remove other impurities from the cask during maturation that may be present.
The subject of chill filtration seems to be an ongoing debate. On one hand, there is a demanding consumer who expects and desires more natural or organic products in their lifestyle choices. And, there those who believe that chill filtering a whisky alters the aroma and flavour. On the other hand, there are those who are caught believing that consistency of color means quality. If lifestyle choices or standards are important to you, then either look for a single malt that is non-filtered or pick a whisky that is cask strength or higher than 46% ABV. Whatever your choice…just enjoy.