The last “Scotch Whisky Uncovered” e-mail which covered the main types of scotch whisky which we categorised as “Single Malt,” “Grain,” “Blended” and “Blended Malt” prompted the following questions from readers;
I plan to cover the “Cask Strength/Chill filtering” questions below and detail the Scotch Whisky regions in the next e-mail – “Scotch Whisky Uncovered 5”
“Scotch Whisky Uncovered” #4 – What is “cask strength and chill filtering
“Cask strength” whiskies are whiskies which are bottled straight from the cask at the alcohol strength at which the spirit has naturally arrived following the maturation process – with no water added to dilute the strength. An above value of 50 to 55% would be a typical cask strength, but natural cask strength could be anything from 40% to over 60% depending on the whisky, cask type, maturation conditions and age.
What is “chill filtering”? As noted in an earlier edition of “Uncovered” when we reviewed the legal definition, the matured spirit has to have a minimum alcohol strength of 40% to be officially designated as “scotch whisky.” Many scotch whiskies are produced at this strength – or sometimes 43% – with water being added to the distilled and matured whisky to achieve the desired strength. However, as water is added to matured whisky straight from the cask, as the alcohol strength drops below 46%abv, the spirit goes “cloudy” as some elements of the whisky such as natural fats go into suspension. This feature is not a problem in terms of taste, but it is undesirable visually as consumers may assume that a problem exists with the spirit. To address this problem, these elements are removed by a “chill filtering” process. The process involves chilling the spirit to a low temperature, running the spirit through a filter to remove the fats which have come out of solution and then allowing the spirit to come back to ambient temperature at which point it will be perfectly clear.
Many whisky buffs/connoisseurs prefer whiskies which state “no chill filtering” on the label as they believe that they are sampling the whisky in its fully natural state. (One comparison often cited is “full” milk versus “semi-skimmed” milk but this is perhaps a bit unfair on the many excellent chill-filtered whiskies!).
Single cask whiskies – and many of the whiskies produced by independent bottlers in particular – emphasise their individuality by promoting the “non chill filtered” and “no additional colouring” features of their products. Single cask whiskies can emphasise the differences in colour that can be produced from whiskies matured in different casks. The large volume scotch whisky producers have to ensure that the flavour and colour profile of their whiskies are consistent from batch to batch and year to year. For this reason, the higher volume producers often add a small amount of colouring to their product. The colouring which is added must be simple caramel colouring.
Please look out for the next edition of “Scotch Whisky Uncovered” facts and tips.
(Please note that if you do not wish to receive any future correspondence from us, please click on the “Manage Your Subscription” link below.)
Thanks for your interest and “Slainte!”