Whisky 101: Part 3. Chill Filtering and Caramel Colouring
In this latest chapter of The Quaich Podcast's Whisky 101 series, we will explore the cosmetic alteration of whisky that sometimes takes place prior to bottling. There are two main processes that are regularly deployed, and often debated: chill-filtration, an industrial process designed to create a crystal clear liquid and colour correction which involves the addition of colourant, in order to change the hue of the spirit.
When diluted below 46% alcohol by volume, whisky can develop a hazy appearance in low temperatures as a result of fatty acids, proteins and esters congealing. Preferring that their customers not be put off by a cloudy dram, the industry turned to a filtration process that would strip away the acids and esters that caused the problem in the first place. The procedure is purely cosmetic, with no benefit to aroma or taste, indeed many feel it has the opposite effect and a growing number of distillers and bottlers proudly declare that there whisky is "un-chill-filtered".
Without ever tasting the same whisky both before and after filtration, it is incredibly difficult to say conclusively that the change is a negative one. Certainly in my own experience, the very best whiskies, the ones that have truly blown my mind, have tended towards the higher strength, un-chill-filtered end of the spectrum and to my admittedly anything-but-expert mind, it seems ridiculous to suggest that there could be no detrimental effect on flavour afterwards. At the very least there must be consequences where weight and mouthfeel are concerned, but that of course is a personal opinion and you know what they say about those.
This is not an attempt to suggest that chill filtered whisky is of a substandard quality because that is demonstrably untrue it simply means that some of us will always wonder what certain drams would have been like had they been left untouched. It must also be noted that it is possible to filter at varying levels, with some producers removing less than others.
In terms of what to look out for, most who avoid chill filtering will shout from the rooftops but as a general rule, anything bottled under 46% has probably been chill-filtered whilst anything 46% or above has likely been left alone. Be aware however that as with any rule, there are exceptions.
Colour correction refers to the process of adding E150 food colouring in order to darken the appearance of a whisky. This is perfectly legal and is done on most occasions for the sake of consistency. Particularly where blended scotch is concerned (though it also applies to mass-produced single malts) every bottle must look, smell and taste exactly the same regardless of where and when it was bought but this isn't an easy thing to achieve with a product as complicated as whisky.
The creation of whisky is a batch process. Even grain spirit which is made in continuously flowing column stills must then be matured in unpredictable oak casks that can produce radically differing results. Immensely skilled master blenders ensure that all requirements are met so far as smell and taste are concerned but colour is another matter. In order that all batches appear the same then, small amounts of caramel colouring are permitted.
Like anything however, the practice can, at least in theory, be abused. Whisky drinkers have been trained for many generations to believe that dark whisky is good whisky. We think that the darker it is, the older and therefore better it is, which is of course, a complete misconception. Whisky that is young and pale can be just as delicious as that which is old and dark but it is said that we first taste with our eyes and there can be no argument as to the appeal of a dram the colour of mahogany. I make no accusation towards any particular company but armed with this knowledge, it is certainly conceivable that some might deploy colouring not for the sake of consistency but to enhance the appearance of their product and that, for an industry that trades on a reputation of provenance, should be viewed as customer deception.
Appearance aside, does the addition of E150 colouring affect the flavour of a whisky? Having tasted the substance myself I can tell you it has an incredibly strong, bitter taste but so very little of it is needed to have a dramatic effect on the colour of a liquid. A single drop in a glass of water for example, will create the appearance of a ten year old whisky. It seems unlikely therefore that it has much, if any, impact on the flavour of the dram in your glass.
The two processes are unrelated but tend to go hand in hand. Whisky that is un-chill-filtered for example, will often state that it has also been bottled at a natural colour. In the end it simply boils down to different techniques for different markets. The biggest brands have to satisfy millions of customers across the world, time and time again. Consistency and reliability are very much the name of the game. Smaller distillers meanwhile can cater purely to the connoisseur, who won't send their whisky back when it turns cloudy. These businesses can concern themselves only with producing the best possible product, even if that means it won't be exactly the same as the last batch. Neither approach is right and neither is wrong, they are simply utilised with different objectives in mind.
In any case, regardless of production method, the most important factor from the consumers point of view is how a whisky tastes. So long as you enjoy it, everything else is immaterial.