Colouring and Filtering Scotch Whisky


Examples of various shades of scotch whisky without caramel colour

There are few practices in the whisky world that are met with with more derision and ire than the addition of caramel colour (e150a), and chill filtration.  Many whisky bottlings now proudly display “natural colour” or “non-chill filtered” on the labels.  This begs the questions, what exactly are these practices and why do distilleries undertake them if they’re so negatively viewed?

What is E150A caramel colouring?

There’s a lot of chemistry behind even the relatively simple concept of caramel colouring, but I’m going to try and keep things absolutely basic as possible.

The “E” in E150A is part of a number scheme used in the European Union for food additives (“E” = Europe).  Within that scheme, numbers 100 – 199 are used for colorants, with 150 being assigned to a range (A – D) of caramels.  Of these four caramel compounds, only the lightest (E150A) known as “plain caramel” can be used in the production of scotch, as specified under the Scotch Whisky Regulations 2009 (link: here).  The rest of the range (B – D) becomes darker in colour as you move through the range, and can involve the use of additional ammonium or sulfite components in its production (these are not used in the productions of A).  These B-D variants aren’t really germane to a discussion on whisky though, so in an effort to remain brief, we’ll focus only on plain caramel.

Plain caramel… Sounds pretty innocuous, right?  At its most basic, it is produced by the “heat treatment” of carbohydrates (ie. food-grade sugars).  So, in very basic terms you heat up sugar and you get caramel.  Cool…. But what is caramel?  It’s sweet.  And now you’re adding that to your finished whisky product.

Now a few statements, out of fairness:

  1. Only a very small amount of caramel colour is required relative to the total volume of the whisky product.  Is the quantity enough (even if the caramel is sweet) to noticeably impact the whisky’s taste?
  2. It’s entirely possible that a little addition sweetness may well improve the final taste profile of some whiskies.
  3. Some large-scale producers of caramel colour state that they are able to produce products that have no discernable taste.  That said, I don’t know if distilleries source those kinds of products, nor whether they are feasibly used in high-alcohol products.

So why is caramel colour used?

This is a little easier to theorize on, and can probably be attributed primarily to consumer behaviour.

First and foremost we have to remember that consumers of whisky are, generally speaking, just casual imbibers.  The enthusiast segment of the market is tiny compared to those who only partake once in awhile, or aren’t interested in learning much about whisky.  Distillers, and certainly larger-scale distillers, have to keep those casual drinkers in mind when plan their production.  

In a mass-production world, we have grown used to uniformity.  If we buy a product more than once, we generally expect the second product to be the same as the first.  As enthusiasts, we understand that whisky production varies from batch to batch.  Taste profiles may differ slightly and, more importantly for this post, appearance may differ slightly.  The provenance and history of use of a cask plays a huge role in the final colour and appearance of a scotch.  If you know that, you may not be overly concerned that the bottle of Springbank that you bought this year is a shade or two darker than the same bottle you bought two years ago.  But if you’re a casual consumer with less knowledge of scotch production, you may be put off buying a new bottle if it suddenly appears different on the shelf.  For mass-market producers in particular, this is behaviour to be deterred.

Additionally, we’ve all been subtly exposed to the notion that darker, richer colours in a whisky imply fuller and more complete flavour profiles.  Again, if you know the role of barrels and aging on the final appearance of a whisky you understand that a dark, rich colour may imply something about the bottle’s expected flavour profile, but it’s hardly definitive, and certainly no definite indication of quality.  But again, there does seem to be the general belief that darker equates to better quality, and if you’re tapping into the casual purchaser, then you want your product to take advantage of that belief.

Ok, enough about caramel already… What’s chill filtration?

Chill filtering of whisky is a process undertaken for (almost exclusively) aesthetic reasons to remove fatty acids created during distillation from the finished whisky.  

This is done by simply cooling the liquid down to the point where the fatty acids precipitate out of the whisky (in the case of single malts 0 – 4 degrees celsius) and then running the material through one or more fine mesh filters.  

In discussing why these lipids should be removed, consider the comments about caramel above.  Producers need to be aware of their casual consumer base and their drinking habits.  The fatty acids can precipitate out of the whisky (ie. become visible) and cause the whisky to become cloudy, particularly if the drink is cooled with water or ice.  Removing the lipids ensures that the drink remains transparent regardless of condition.

Further, non-chill filtered whiskies are typically bottled at 46% ABV or higher, as to drop below that alcohol level makes the solution of lipids in the whisky less stable, and more prone to precipitate out and form mistiness, even at room temperature.  This means that even if the chill-filtration process adds an extra process step and cost to the whisky production, that cost may well be offset (at least in part) by the ability of the producer to bottle its product at a lower ABV.

So are these things bad?

So we have two practices that are in place for aesthetic reasons, and generally looked down upon by the scotch enthusiast community.  But are they bad?  

In the case of chill-filtration, the argument against it is primarily that by removing part of the flavour-containing fatty acids in the whisky you are then curbing the final product’s flavour potential.  This makes a certain amount of logical sense, though the reality of that statement is difficult to test, given that (to my knowledge) no producer releases the same batch of whisky both filtered and unfiltered.  Horst Luening of conducted an interesting experimental survey (link: here), wherein he took 24 samples of unfiltered whisky, filtered half of their volume (two create half filtered and unfiltered samples of the same whisky) and then distributed both samples as blind taste tests to over 100 panelists.  It’s a very interesting tasting experiment that’s worth reading in its entirety, but, in essence, he found that there was no evidence to support the notion that unfiltered whisky is preferable in taste to filtered whisky.  Granted this is only one experiment on the subject, but it’s also by far the best-conducted investigation into the subject that I’ve been able to find.

In the case of caramel colour, again it’s a difficult thing to test given that no bottlings are released in coloured and uncoloured variants.  Further, we also don’t know the specific formulation of the plain caramel used in many coloured whiskies.  It may be that there are added sweet (or even bitter) notes that come from caramel additives, but as mentioned above, there are certainly commercially-available products that claim to have zero taste impact.


At the end of the day, we have two processes here that probably have very little impact on the final whisky product.  There may well be connoisseurs out there with extremely well developed palates, who may be able to discern differences more acutely, but for the vast majority of whisky drinkers, we won’t notice any difference.  

My own personal aversion to colour and filtering of whiskies (though not particularly strong) is mostly because I would prefer to experience the final whisky product as close to its state coming from the barrel as possible.  In an ideal world I would love to have a natural, unfiltered, barrel-strength bottle that I could sample and dilute progressively with water to my own taste.  I’m sure I’m not alone in that, but that’s also not a reasonable commercial expectation (though hoping for 46% ABV or higher is not too unreasonable!).

So at the end of the day, I’d probably be happy if these two practices went by the wayside, but I’m also not going to hold a distiller’s feet to the fire for doing it. In fact, after doing a little research for this particular post, I’m even less inclined to discuss colouring or filtration as negatives than I was going in.

2 thoughts on “Colouring and Filtering Scotch Whisky

  1. The more I drink whiskey the increasingly concerned I get about added caramel.
    You only need to taste the cloying sweetness of a Jura to get that caramel hit.
    My biggest bug bear is the fact there is no legal obligation on the producers to inform you of the added colouring.
    In most other food & drinks products this is a basic.
    Why not in whiskey?


    1. You’re right… At the end of the day added caramel is still added sugar, and when done in great enough quantities it may well add that cloying sweetness. That said, I often wonder how much of the experience is our own expectation. If we know
      something has caramel in it, do we automatically begin to taste that sweetness because we’re looking for it? I don’t know, but that’s why I find the few blind taste testings available so interesting.

      As much as I’m trying to keep an open mind about caramel, I still would far prefer to see the most natural product possible in the bottle (especially in older/high-end bottlings). And absolutely I agree with you that they should be required to print on the bottle exactly what’s being added.

      Liked by 1 person

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