Chill Filtering Explained
Guest post by Lukasz Dynowiak
Those of you who read labels carefully know that every bottle of Balblair Single Malt states that the whisky has not been chill-filtered. Most of you probably have a rough idea what that means or at least suspect that it's probably a good thing. Refraining from chill filtering single malt whisky has gained in popularity in recent years but while often quoted in promotional materials, the difference between chill-filtered and non chill-filtered whisky is not yet widely understood by the single malt community. And so in the spirit of always trying to make all things Balblair as clear as possible, bar those instances when chill filtration would have to be involved of course, I thought I'd try to explain the process and the effect it has on the liquid in your glass in a bit more depth than a single line on the label.
Clear as a whistle. Or is it?
In its natural state whisky is prone to throwing a haze and over time light sediment may appear in the bottle. It's a function of temperature and alcohol content, the colder the whisky and the lower the ABV, the more haze there is likely to be. All whisky will go cloudy if you cool it enough but between roughly 40% and 46% the haze will form at room temperature and there is precious little you can do about it. And since roughly 90% of all Scotch sold world-wide is blended whisky of which most is not only bottled at 40% ABV but usually served over ice, you can imagine that this lack of clarity was once commonplace. Somehow over time it became undesirable, the consumers didn't think it looked very premium, and the whisky industry came up with a clever way of removing this slight cosmetic problem. Enter chill filtering.
The Incredible Machine
A chill filtering unit is a fairly simple piece of equipment. Whisky which has been cut down to a desired strength is cooled down to around 0°C (temperatures may vary depending on the exact chemical composition of the whisky you're 'treating') which makes certain fatty acids, proteins and esters, the main culprits of clouding, precipitate or 'go out of solution'. The whisky is then pushed through a series of fine filters which to me look a bit like thin pieces of plaster board, smooth on one side and rough on the other. The number of filters matters, the more of them, the clearer the whisky is going to end up but the more of it you're going to lose along the way. The whisky is then returned to the ambient temperature and voilà, no more haze.
Well, it's not all rainbows and rose petals Especially if, like me, you're a single malt fanatic. The very thought of something being taken out of my whisky before it's bottled makes me shudder. If you live and breathe whisky, every nuance matters, no matter how slight. And having blind-tasted the same whisky before and after chill filtering on a couple of occasions, I can assure you that it definitely does make a difference. The industry has told us for a long time that chill filtering changes neither the aroma, nor the flavour of the whisky. And that's by and large true! But while the variance in taste may be almost imperceptible, the non chill-filtered drams invariably have more body on the palate and better flavour retention on the finish. And that's precisely why all Balblair Single Malt is now non chill-filtered, period.
Hazy is the new clear
This move to 100% non chill filtering has an important implication on the strength of bottling. To keep the whisky nice and clear in the bottles Balblair now keeps all expressions, including the youngest vintages, at 46% (or more in case of cask strength bottlings). The 46% won't stop your dram from going hazy if you add ice or a touch of water. But as we are a slightly better whisky-educated bunch than our forebearers, the honourable imbibers of the olden days, we know that haze means extra goodness in the glass. Hazy is, well and truly, the new clear.