If you hang around people who love whisky, you have probably heard a lot about chill filtering. This process is used often in whisky production, but many distilleries have begun skipping this step and proudly proclaiming this on their labels. While many people have an opinion about chill filtering, few actually understand what it is or how it affects whisky.
What If Chill Filtering?
Chill filtering happens in the exact manner that the name suggests; whisky is cooled and filtered. To be exact, it is cool to about 0 degrees and filtered with a metal filter. When the whisky is brought down to this low temperature, unwanted substances such as fatty acids, esters, proteins and lipids clump together and get stuck in the filter. This also removes larger impurities such as coal and organic matter.
Chill filtering can remove a small amount of matter or a relatively large amount, depending on several factors such as the pressure and speed with which whisky is pumped through the filter. It can also vary with the filter and also with the number of filters if there is more than one.
So What’s the Problem?
While removing impurities can sound like a good idea—no one wants to choke on a barley husk while sipping their favorite whisky, after all—there are drawbacks as well. Esters and fatty acids in whisky often donate a huge amount of flavor. Chill-filtering removes almost all of them. It is certainly not a step in the traditional Scotch whisky making process. On the other hand, whiskies that are not chill-filtered may develop sediment over time or turn cloudy when poured over ice or mixed with cold water. Advocates of chill-filtering also argue that the esters and other filtered elements are not an essential part of the whisky and may actually add unpleasant flavors and textures.
What Whiskies Are Chill Filtered?
One good way of deciding whether you like chill-filtering is to try both types of whisky. Select two whiskies in the same class and price range, one chill-filtered and one not. Perform your own taste test and see what you think! However, few chill-filtered whiskies actually advertise it. You can tell if a whisky is not chill-filtered because it usually will say as much on the bottle. In addition, some distilleries, such as Bruichladdich Distillery, do not chill filter any of their products. In addition, most cask strength whiskies are not chill filtered, although it is obviously unfair to compare these to normal, diluted whiskies. Some whiskies, such as Te Bheag, offer both chill filtered and non-chill filtered versions of the same whisky. That may be the best way to begin educating your palate about the matter.
Chill filtering is beginning to become somewhat of a controversy among whisky lovers; we all love a clear, well-balanced dram, but we also want to experience the traditional craft of whisky making in all of its glory. Some people insist that chill filtering does not affect the whisky at all, but it is difficult to see how this can be true. Whether that change makes a difference that negatively affects the whisky is in the eye of the beholder.