What Are Cask Strength Whiskies?

A Cask Strength Whisky is one not diluted with water to drinking strength when bottled. Typically this a stronger whisky with over 55% ABV though can in practice be far lower. This distinguishes strong bottling from regular versions, which often have an alcohol content of between 40 and 46% and are diluted with water when bottled.

Alcohol is an excellent flavor carrier and so Cask Strength Whiskys are considered the fuller, more intense, complex bottlings. Some connoisseurs consider a whisky at cask strength to be a more honest representation of the distillerybeing bottle directly from the cask. Nevertheless, several single malt casks are often married together at Cask Strength, so they should not be confused with single cask bottlings (single cask whiskies). Strictly speaking, while cask strength has nothing to do with the absence of chill-filtration or the addition of e150A, these criteria can generally be taken as given. ‘Cask strength, Non-chill-filtered, & Natural colour’ is the standard label.

What is the cask strength and why is it always different?

Almost all Scottish malt whiskies are distilled twice (occasionally three times) in copper stills. Double distillation increases the alcohol content to around 70% ABV, triple and continuous. Even before it is filled into cask, the strength of the New Make sprit is set to a lower value, typically around 63.5% ABV. though this often varies by a few percentage points. During maturation bond the whisky’s alcohol content is reduced year on year. The so-called Angels Share, i.e. the proportion of whisky that continuously evaporates through the barrel walls to blame. At most Scottish distilleries, it is 1-2% annually at the beginning of storage, slightly less in older age, in other countries it can be far higher at around 12%. How much alcohol actually evaporates depends on the barrel (e.g. size and age) as well as on the environment (including temperature, humidity).

After a maturation period of 10 to 12 years, the alcohol content of a whisky in a wooden barrel is reduced to around 60 percent. That is the barrel strength, which is only shown when the single malt is bottled at this age. Since each whisky matures differently in the oak barrel, the cask strength is always different in the end. With regular monitoring and their experience, the Master Blender and his team ensure that each barrel is filled at the right moment at the desired strength.

What is the minimum alcohol content of a cask strength whisky?

In fact, the term cask strength is not linked to the actual alcohol content. If you store a malt whisky in a wooden cask for 30 or 35 years, then after many years of maturation it often only a little over 40% alcohol. In this case the cask strength is at the absolute minumum but still a Cask Strength Whisky. A good example is the Laphroaig 25 years, after a quarter of a century it has fallen to 46.8% ABV in the cask and is yet offered as Cask Strength.

If the ABV falls below the minimum 40% the spirit can no longer legally be sold as whisky (in this instances however several barrels of similar age can be blended to increase the alcohol content to meet the minimum requirement). In practice, however, it is often younger whiskies that are explicitly filled as cask strength and these have a higher average alcohol content of around 55% ABV. Frequent intermediate strengths such as 46% or 43% for younger single malts are almost always caused by dilution, only that, compared to the minimum standard of 40%, a little less water is added before bottling.

Why is whisky filled at 40% ABV?

Up until the First World War, whisky was mostly bottled in Scotland with a strength of 44.6 to 48.6% ABV. The distilleries knew very well that a higher alcohol content was beneficial to the taste and aromatic depth of the whisky. Since 1915, UK tax laws have been continually adjusted to reduce the strength of alcoholic beverages such as whisky. It was the time of the abstinence movement, a war was coming and the soldiers should not drink too much and too much. At least that’s the plan of David Lloyd George, the Chancellor of the Exchequer of Great Britain. A revision of the tax laws he initiated in 1920 finally made it more unappealing for distilleries to fill whisky with more than 40%. As a result, the standard value prevailed and has persisted to this day.

One should not hide the fact that the lower alcohol content of 40% also has advantages for the whisky distilleries: For example, significantly more bottles can be filled from a barrel of malt whisky by diluting it with water. This remedy can of course also be used if a distillery notices that you are running out of some older malts, for example. Then the strength of special bottlings is reduced from 46% to 43% and the whisky lasts longer.

An important visual effect is closely linked to the dilution to 40 to 46%: If you add water or ice to a whisky of this strength, it can become cloudy (the so-called “whisky haze” occurs). This effect is often undesirable, as many connoisseurs prefer clear whisky without suspended particles (at least that’s what the sales and marketing staff believe). This effect does not occur with unfiltered whiskys that are stronger than 46%.

Is barrel proof the same as cask strength? When talking about Cask Strength Scottish whiskys when it comes to cask strength, the term barrel proof has become common for American whiskys. This is also due to the fact that bourbon barrels are called barrels in the states and the alcohol strength is given in the unit proof.

How do you properly enjoy Cask Strength Whisky? Pouring a dram and enjoying it at the same time is not so easy with Cask Strength Whiskys or it just doesn’t do them justice. On the one hand, most of the bottlings are very strong at around 60%, the alcohol is clearly present and can be anesthetic in the mouth. The flavors that you actually want to taste are often overlaid by him.

Die eigentliche Freude an Cask Strength Single Malts entsteht beim Experimentieren mit ihnen: Denn durch Zugabe von etwas Wasser kann man den fassstarken Whisky aufschließen und Tropfen für Tropfen auf die persönliche Trinkstärke reduzieren. Und die kann eben ganz unterschiedlich sein und wird häufig nicht bei genau 40 % Alkohol liegen, sondern bei vielen eher etwas darüber. Als Faustregel kann man sich merken, dass ein Teil Wasser auf drei Teile Single Malt den Alkoholgehalt von rund 60 % auf 45 % senkt.

Of course, a single malt can also be diluted with 40% with water and digested. But if you try this out, you will quickly find that the possibilities are limited. In this drinking strength, the whisky often simply does not offer enough potential for dilution, so the flavors tend to become even thinner with water. It is different with Cask Strength whiskys, which often show a variety of aromatic facets and reveal new dimensions with every drop added. The taste impression changes continuously, which contributes decisively to the enjoyment of strong whiskys.