Look at most labels on a bottle of whisky and you will see indicators (in most cases, poor ones) of what’s inside. Age, distillery, finish or maturation, the strength etc. Some brands are even kind enough to indicate what the contents might actually taste of which seems to be a radical move as it is certainly not the normal practice. Now and then you will see the words “non-chill filtered” which indicates another process the whisky has undergone (or not) before bottling.
Great. So it’s non-chill filtered. That’s reassuring to the purchasing consumer isn’t it and helps him justify the price based on those words and the higher alcoholic level. Well no, actually it does neither. Labels on whisky are still, like labels on French wine, unfathomable to most and no indicator of the quality within. Brands seem to be approaching this from two sides, either wholeheartedly throwing out the rule book such as Balblair, Glenrothes, Wemyss and others. But others seem frightened of alienating the old guard of customers who might be shocked not to see a highland cow on a label, or a misty glen of reassurance that it’s authentic and traditional scotch. What a load of bollocks.
Anyway, I could go on (and on and on) about various aspects of this, but I want to concentrate on just one. The chill filtered bit.
Chill filtration is a process employed by some distillers at the point between removing the matured whisky from the cask and bottling it. All whisky is filtered to remove any residual particles that may be have been picked up from the cask itself by passing it though fine gauze or absorption filters. This can be done without chilling the whisky and simply passing it through the filter. But this simply approach leaves fatty acids, fusel oils and other hydrophobic elements in the whisky which will cause a haze when the whisky is cold or the whisky will turn cloudy when water or ice is added.
By chilling the whisky those elements responsible for causing a change in appearance will clump together and become too large in their composition, stopping them getting through the filter. The haze is only noticeable in whisky below 46% ABV, although it all depends on where the distiller has chosen to “cut” the still run.
Once the still is heated, the heads or foreshots are the first parts in distillation to come over the still and contain some of the lightest alcoholic elements such as methanol. From then on, various compounds will each in turn become activated and vapourise and pass over the neck for collection. Distillers will usually direct this first run back into the wash still for re-distillation. The later part of the run know as the tails or feints is where we see the temperature of the spirit in the still reaching top levels, and thus the start of water elements coming through along with the heaviest alcohol elements (fatty acids and fusel oils). Each element has it’s place in creating the style and character of the whisky, but it’s the choice of the distiller to decide the point where he switches from diverting the heads to collecting the heart and again switching off as it enters the feints stage.
The longer you wait or cut into the feints, the more heavier elements you bring over the still neck which will produce an oily spirit, heavy and rich. If the wash is from pleated barley, then you will actually want to hold a deep cut as the phenolic elements which carry the smokey nature are found in this latter part of the process. You can see this most apparent with Islay examples such as Laphroaig Quarter Cask which is at 48% abv against something much lighter such as The English Whisky Company Chapter 6. Pop a sample of each in a glass, say 50ml and add 5 ml of water to each and see the difference. Laphroaig will haze much more as the cut from the still is deep into the feints to ensure the classic phenolic and oily nature of the whisky is maintained. The English example, which is unpeated, cuts early in the run, avoiding the weightier elements and as a result, the haze is a lot less….in fact, David Fitt, the master distiller at TEWC indicated recently that even at 43% abv their spirit did not have a haze, despite being no-chill filtered.
Many people believe that chill filtration will cause some of the congeners (the esters, aldehydes, acids and higher alcohols contained in the distillate) are hampered and as the elements “clump” together in the cold state, they trap some of the other elements that would otherwise pass through, effecting the final character. I’m not entirely sure this is the case or if it is would we be able to pick up the change? What I do know from the many tasting we have held with Dramatic Whisky is that consumers note the “oily” and heavier mouth-feel to the whisky which most of the time helps belay the higher alcoholic amount and creates a rounded, fuller whisky.