Why do people care about chill filtration so much?

If you are a regular to this blog you will know constantly and consistently I bang the Non Chill Filtered (NCF) drum. Why do I care so much and am I correct to be giving such kudo’s to the lack of a process which is meant to guarantee “quality”.

For any product on the market that you care to think of, each stage of the process is there for a reason. In the case of scotch whisky it is matured in Scotland because it legally has to be and it is matured in oak again because legally it has to be. No amount of cost cutting measures can change that. Why then is whisky put through an expensive piece of equipment? What problem is it trying to solve?

The problem to solve is the stability of the liquid when additional water is added by the consumer. For a whisky bottled at under 46% ABV (reader take note) the impurities in the whisky can cause it to cloud up when water is added. This could give the impression to a consumer the whisky is somehow defective or contaminated.

The solution to this problem is to remove these impurities from the liquid before bottling. The impurities are natural fatty acids, proteins and esters and can be removed fairly easily. The process in use is fundamentally as follows:

1. Cool the whisky down so impurities solidify
2. Fire the cooled whisky through filter paper
3. Bottle the resulting liquid

Problem solved right? Now when we add water the visual impression of the liquid in the glass does not change. There is one massive side effect to all this though. If we go back to our filter papers and swap in some new ones we will notice the things stink! A strong, delicious smell of pungent complex whisky. Strong pungent flavoursome compounds which were in the whisky and now are not.

This is the precise reason why I have a problem with chill filtering whisky. The process partially removes all the hard work of maturing that whisky for potentially decades. It seems like madness to invest all that time and money in delayed profits to then stick your flavour to some discard-able filter papers.

However, all is not lost dear reader all chill filtration processes are not created equally. The amount of devastation done to the whisky can be controlled by careful control of the temperature of the whisky, velocity of the whisky through the filters and the granularity of the paper. The warmer the whisky, faster the velocity and coarser the filter the less flavour is extracted but equally the greater the probability of instability in the consumer’s glass.

Below is an extract from a website manufacturing chill-filtration equipment to expand on this point:

Filtration at 3 to 7 degrees C is commonly referred to as attemperation and many whiskies are filtered within this range. The effect on flavour is minimal and chill haze stability is normally good although higher malt content whiskies could be expected to show a haze under certain conditions.

Filtration at -5 to 0 deg C would be correctly called chill filtration and a distict effect on flavour could be expected. Whiskies filtered at this temperature would be very stable although a slow deposition might occasionally be encountered.

Filtration at -10 to -5 deg C would offer maximum protection BUT could have a very significant effect on flavour.

So if everyone seems to agree NCF is the way forward then why does it still go on? Why are cost conscious multi national corporations throwing good money after bad when lets be honest this is a modern day step in the whisky process. Thankfully Glenlivet were nice enough to write a marketing post on the issue. The blog post can here found at https://uk.theglenlivet.com/chill-filtration-what-it-is-and-why-we-use-it/

The important paragraph has been copied below for your convenience:

Does removing this haze actually affect flavour, or is it superficial?

Human perception of flavour is complicated, so some of us will find whiskies less palatable if they’re hazy. It’s difficult to define what’s a true difference in flavour and what’s just perceived. Over the years, this has been debated constantly.

A clearer liquid can be seen as a sign of quality, but some people feel that by filtering out specific compounds, you’re taking away flavour or changing the mouthfeel. In taste tests, non-chill-filtered whiskies are often judged as “fuller”, “rounder” and “richer” than their chill-filtered counterparts.

George Smith didn’t have the option to chill-filter The Glenlivet. These days, we chill-filter most of our expressions – all, in fact, other than the Nàdurra range. Conduct some taste tests of your own, and see what you think.

So what they are basically saying is their core customer’s, in their opinion, taste whisky with their eyes which overrides the inherit quality within the liquid itself. The interesting part is their Nadurra range is the only ones not filtered. The ones directed towards to the experienced whisky drinker basically. This at least proves producers understand for the consumer who really cares about the whisky they buy they really do value a purer approach which harks back to days gone by when whisky was level industrialised.

The last thing I want to mention here is that at the top of this post I mentioned this haze problem only happens when  you bottle whisky at less than 46% ABV. This is also missing from the Glenlivet blog entry as it happens which is not surprising. The real solution to producing clear whisky which does not haze up is to only bottle at 46% or higher and do no filtering. That would definitely cost prohibitive for the younger volume core range bottles you see in every shop that sells spirits.

That is the REAL reason whisky is chill filtered.