Chill filtration - what is it and should I care?

Whisky, the amber nectar, undergoes a meticulous journey from grain to glass, with each step influencing its character. One step in this process, often maligned by whisky drinkers, is chill filtration. In this exploration, we delve into the intricacies of chill filtration, its impact on whisky, and the age-old debate on whether we should care about the process or not.

Understanding Chill Filtration

Chill filtration is a technique employed during whisky production to remove certain compounds that may cause the spirit to become hazy or develop sediment when it is cold. After maturation, whisky contains fatty acids, or long-chain ethyl esters, that can form a residue in the liquid at low temperatures. Chill filtration involves cooling the whisky to near-freezing temperatures and passing it through a series of fine filters to remove these particles before bottling. The main purpose is to ensure that the whisky itself is always clear, even at low temperatures.

One important point to note is that whisky with an ABV above 46% does not suffer from this. At this strength the esters remain soluble in the liquid and will not clump together to form the dreaded haze, even at cold temperatures! It is also worth remembering that all whisky is filtered to some degree to remove any solid components picked up during the distillation or, more likely, maturation process.

The impact on whisky

While chill filtration serves a practical purpose, it is not without consequences. Some argue that this process of removing some of the esters may strip the whisky of certain congeners, flavourful compounds that contribute to its complexity. The removal of these compounds can alter the mouthfeel and taste of the whisky, potentially sacrificing some of its richness and depth.

Should we care? Aesthetics vs Authenticity

Very few side by side test have been run, especially with blind testing to ensure rigour. Therefore it is difficult to say for sure what impact there is on taste. Whilst some distillers will claim to have done these tests it is often coupled with an explanation as to why they have chosen to chill filter their expression (or not). It has frustratingly become more of a marketing term for the distillers.

The debate over chill filtration in whisky production is a long-standing one. Traditionalists argue that it interferes with the integrity of the spirit, diminishing its natural complexity. On the other hand, proponents of chill filtration emphasise the importance of visual appeal and stability, especially when appealing to new drinkers who are unaware of the potential presence of haze in the liquid.

In a world where presentation often plays a significant role in consumer perception, the clarity of a whisky can be a selling point. However, this raises the question: Should aesthetics take precedence over the authentic and unadulterated expression of the spirit? It's a dilemma that whisky enthusiasts must grapple with, weighing the visual appeal against the potential sacrifice of flavour nuances.

The changing landscape

In recent years, there has been a growing trend among distilleries to release non-chill filtered whiskies, catering to a market that seeks a more authentic and unaltered experience. The movement encourages transparency and a return to the traditional methods that showcase the true character of the whisky.

Conclusion

As whisky enthusiasts, the choice between seeking out a chill-filtered or non-chill filtered expression ultimately boils down to personal preference. Some may prioritise choosing a whisky that guarantees visual clarity and a pristine appearance, while others seek the unbridled complexity of a whisky left untouched by chill filtration. In the end, the beauty of whisky lies in its diversity, and whether or not we care about the chill filtration process is part of the ongoing dialogue that makes the world of whisky endlessly fascinating. So, the next time you savour a dram, consider the journey it undertook, and decide for yourself whether the process matters as much as the pleasure it imparts.

The Glenlivet distillery is refreshingly transparent about the choice they have made to chill-filter their whisky and why, read more here. Bruichladdich also explain why they choose not to chill-filter their whisky, available in their FAQs.