chill filtration is a process in which barrel-matured spirits are chilled to between −10° C to 4° C and then filtered through a membrane to remove molecular compounds such as fatty esters and other sediments suspended in the liquid. These compounds can cause whisky to haze when exposed to low temperatures, as in the addition of cold water or water. Distilleries that skillfully chill-filter can tweak the filter material, its porosity, its thickness, and the pressure and temperature of filtration—all conditions that will reduce the haze-inducing elements but also subtly alter the taste and texture of the final product. This increased clarity, improved liquid stability, and, its proponents claim, enhanced flavor are the main goals of chill filtration. Opponents of the process—and there are many—believe that eliminating the fatty esters and other molecular compounds diminishes mouth feel and taste. However, in a 2014 comparative blind tasting of over a thousand whiskies by 111 whisky connoisseurs, the chill-filtered whiskies received essentially the same ratings as non-chill-filtered whiskies.
Lüning, Horst. “Study on the Chill Filtration of Scotch Single Malt Whiskies: Comparative Assessment of a Blind Tasting.” Whisky.com, 2014. https://www.whisky.com/information/knowledge/science/study-on-the-chill-filtration-of-scotch-single-malt-whiskies.html (accessed February 24, 2021).By: Heather Greene