Well, this article could be quite short. The Colour comes from the cask and, if added from caramel colour (E150), on the other hand a filtration does not alter the colour. That’s it. I guess that this is something even a non Whisky drinker might know. Maybe the colouring with E150 might not be that widely known, but that the cask has a major influence on the Whisky is common knowledge. Everyone satisfied with this information can stop reading. But this short sentence does leave some questions open. And I’m going to answer – at least I’ll try – these in the following two articles.
What happens to a cask before it is filled with New Make/White Dog? How does the cask influence the colour of the final Whisky? Does it matter what was in the cask before? What’s E150 at all? Do I have to use it or can I use something different? How much E150 is used commonly? Why do you said something about filtration, if it doesn’t affect the colour? And only to prevent any misunderstanding: When I speak about unfiltered Whisky I mean non chill filtered Whiskys, nearly every Whisky is filtered, only some Whisky is chill filtered, some non chill filtered, but I’ll come to that later.
In the Scotch Whisky Regulations 2009 (SWR) we find everything we need to follow so that the product may be called Whisky. I couldn’t find anything (correct me if I’m wrong) that a used cask must be used. I found just this: „… that has been matured only in oak cask of a capacity not exceeding 700 litres.“ In other words, the distillery can do with their casks what they want. Usually they toast the cask before usage to get a charcoal layer inside the cask. The heat not only forms this additional filter layer, it also caramelizes the sugar in the oak. Depending on the temperature and duration of this toasting the thickness of this layer will vary accordingly. And this influences the colour and sweetness of the Whisky too.
Of course the pre occupation of the cask is something that influences the outcome of the maturation. Red wine, white wine, Bourbon, Sherry, Rum, new or used, of course the oak interacts with the liquids it touches. And when the New Make or Whisky is poured into the cask it starts interacting with it too. It also matters, how often the cask was previously used, say a 2nd fill ex-Sherry cask will give less flavour and colour than a 1st fill ex-Sherry cask. Before we turn to what E150 is, the SWR allows to add only water, E150a, or water and E150a to the Whisky. Anything else and you aren’t allowed to call it Whisky anymore. And yes, there are more than one E150, to be specific a, b, c and d.
E150a, caramel colour, is a black(!) colour which may be used to colour food and beverages. It is produced (as the other three, there are just slightly differences on how exactly they are made and what they can be used for) by heatingsolution of sugar or to be a little bit more chemical, carbohydrates. Depending on the class (a, b, c or d) sulphuric acid, as well as ammonium may or may not be used. For the colouring of Whisky neither of these two chemicals may be used. Instead phosphoric or citric acid can be used, as well as sodium or calcium hydroxide. As a chemist I can tell you that these and the previously mentioned substances are quite strong oxidising agents and quite harmful! Of course these chemicals react during the formation of the finished product and will not harm anyone who uses a product coloured with it. There are some critical voices that there might be some health issues but I’m no doctor to confirm or dismiss these allegations.
Despite the fact that only a few drops (I’d guess that might be an understatement) to some hundred millilitres (more likely) are used to colour a batch of several hundreds or even thousands litres, lots of (Whisky drinking) people don’t like the idea of a coloured Whisky. But why is that? The tasted is not influenced, at least everyone is saying that. Wikipedia states that the taste of caramel colour is bitter, but of course that is the concentrated product. I don’t think that a few hundred millilitres will change the taste of the Whisky. So why is adding a little bit of colour to the Whisky „that bad“? I’ll try to answer that question together with some pros and cons on colouring and filtration in my next article!