Chill filtration is the process by which whisky (or whiskey) at the bottling stage is cooled to below freezing i.e. under 0 degrees Celsius and it is forced through a series of filters so as to remove the physical particles that are in the whisky so that when the whisky is bottled it’s lovely crystal clear and looks like a highland spring.
They use wood pulp cardboard, it’s perfectly natural, it’s inert and it does not affect the flavour of the whisky. What it does is removing mainly the oils. What happens is, when malted barley, or whatever grain you’re using is first milled, fermented and distilled a certain proportion of the oils in that grain will come through the process which means that you have, in your finished product, in your whisky bottle something which may look slightly hazy it’s known as Scotch mist.
I’ll show you, here is a branded whisky which will be familiar to many people; Johnnie Walker black label Good blend, I recommend it, it is consistent good quality, more about that later but it is a branded whisky and as you can see it’s a lovely colour because it’s got caramel in it and it’s crystal clear like a Highland spring. For the simple reason that that is what people who buy blended whisky expect and want; consistency, continuity and reliability of the brand.
Single malt drinkers are paying a lot more money for single malts than people who are buying blended malts, because blended malts are generally cheaper apart from the extravagantly packaged ones (such as Johnnie Walker Blue). So here we have an example of a very fine single malt whisky this is the rather excellent signatory of which I’m rather partial unchill-filtered, natural colour. So there is no caramel in this and it hasn’t been put through the filters.
Now I’m going to hold the bottles close so you can see the difference, chill filtered, with some caramel added, nice and clear, nice and dark and tasty. Non chill filtered, no caramel added, it looks paler and slightly hazy, not a problem. In fact it’s something to be encouraged if you have a more naturally presented, essentially raw product in the bottle it’s a good sign that the flavour is more rounded, more intact, has more depth and has better mouthfeel. It’s not a huge difference but when you’re paying the money you’re paying for single malt whisky that difference makes all the difference.
Now apart from chill filtration another phenomenon you might have encountered which I’m going to mention briefly is sediment, particularly in artisan whiskies. Now I’m going to hold this bottle at the end there, you may notice at the bottom of this bottle there is a deposit it looks slightly powdery, like a sediment in a port, perfectly natural.
What is it it’s just little bits of barrel, whisky is matured in barrels, oak barrels are living things, whisky is a natural living phenomenon and it’s perfectly natural that sediment will appear. It doesn’t do any harm, all it means is that the whisky has been barrier filtered i.e. put through a sieve but it hasn’t been chill filtered to remove any of these tiny little particles whether it be oils or whether it be little bits of sawdust and as a result you have a more full flavoured whisky.
And entirely to be encouraged so don’t be frightened by hazy whisky or by tiny bits of sediment in your bottle of whisky. If you want rid of it, if you want rid of that little haze down their all you have to do is get a funnel a piece of kitchen towel or a coffee filter and to strain the whisky. If you’re concerned that the whisky might be tainted by the coffee filter or the kitchen towel, no problem just get some blended whisky, or vodka and just wet the filter first it’s not going to be a problem.
So there you have it folks, chill filtration and what it’s all about.