The world of spirits, like any other field, has its own vocabulary that can be quite opaque to those who are new to it. These terms are often used imprecisely, or even with multiple meanings.

However, some of these mysterious words, such as single cask and navy strength, have precise meanings that can help us understand what the label on a bottle is telling us.

Let’s start with single cask, a term that originated in the world of whisky but has since expanded to other categories.

— Single Cask

This could be translated into “from a single barrel,” but this seemingly simple phrase reveals several elements.

Most whiskies are the opposite of a single cask; they are blends, meaning they are a combination of whiskies from different barrels, distilleries, and even whiskies made from different types of grains.

Whisky relies on the art of master blenders, people with a heightened sense of smell whose work, of crucial importance, involves blending different whiskies to achieve specific characteristics.

Obviously, to choose the whiskies to blend and in what proportions, the master blenders must taste the contents of very many barrels and do so at different times (because liquids are constantly evolving). But what happens when they find a truly exceptional whisky, a barrel that, for some reason, has given those 200 liters of whisky exceptional characteristics? Well, they don’t blend it. And the 260 bottles on average that come out of a normal-sized barrel are bottled as single cask.

What’s the magic for a consumer? Well, knowing that they have something unique, limited, and very specific in origin: it comes from a single barrel, so a single distillery, and it’s probably made from a spirit derived from a single type of grain (but not necessarily). It’s a bit fetishistic.

— Navy Strength

This naval term is mainly associated with the world of gin and, to a lesser extent, rum. It refers to spirits bottled at 57% alcohol by volume (gin and rum start at around 40% ABV) and, although many legends circulate about its origin, it’s actually very pragmatic.

It’s said that the British Navy required its suppliers to provide gin at this strength because it’s the amount of alcohol needed to ignite wet gunpowder. If their explosives were accidentally wet, they could regain their war potential by soaking them in gin. Although it has some historical basis, this claim isn’t entirely true.

In fact, the Navy required this alcohol content from its suppliers because, before there were tools to measure the alcohol content of a drink, hydrometers, the only way to determine the alcohol content of purchased gin (or rum), and thus be sure it wasn’t a diluted spirit, was to make a paste with gunpowder and try to ignite it. If it ignited, the spirit contained 57% alcohol.

But why did naval armies buy rum and gin? Because soldiers of a certain rank and officers received a daily dose as payment or reward for their services to their country.

Navy Strength has a similar meaning to overproof, although the latter isn’t as precise. Any spirit that exceeds by a certain margin the minimum alcohol level to enter its category can be called overproof, and this margin is usually around 50% ABV.

What does a navy strength or overproof spirit mean? It contains more alcohol than average, which is useful for cocktails. For example, Bacardí Superior Heritage, which contains 7.5% more alcohol than usual, is ideal for making Daiquiris because it balances citrus flavors better and gives a stronger character. Alcohol gives structure to cocktails.

As for gin, if you want to try the navy strength that’s attributed to the origin of the term, you should try Plymouth Navy Strength. It’s a potent gin with notes of coriander and cardamom, a silky texture, and a spicy finish (due to the extra alcohol).