Bar History: What's Navy Strength Rum?

How did that sailor get drunk in the first place? Drinking navy strength booze, probably. Fun fact: rum was issued as a daily ration to the British Navy until July 31st, 1970. This date became known as “Black Tot Day” to mourn the end of the daily rum ration tradition that started way back in 1655. But what is navy strength booze in the first place, and where can you find it?

How strong is “navy strength” rum?

Prior to 1816 there was no hydrometer that was capable of accurately measuring the strength of spirits. To make sure they weren’t getting taken advantage of and being sold watered down rum, the British Royal Navy mixed a small amount of the spirit with gunpowder and then attempted to set it on fire. If the liquid set alight then the rum was proved to meet a minimum strength and could be described as being “overproof.” In fact, it was this exact method of testing spirit strength that led us to use the term “proof” today! After the adoption of the hydrometer, the point of flammability that the navy tested was discovered to be 57% alcohol by volume - a pretty strong rum indeed. By today’s standards that’s 100 proof liquor. Drinking like a sailor is no joke!

Is that all it had to do with the navy?

No, actually. Navy strength rum did more than make the navy merry. It quite literally preserved the fire in the belly of the ship! Should the gunpowder become soaked at sea or in the midst of a battle, it was critical to preserve its flammable properties. Making sure that the rum was above a certain strength would ensure that rum soaked gunpowder would stay explosive in case the firepower got wet while out on the sea.

What changed after the hydrometer was popularized?

Not much! Following the invention of the Sikes’ hydrometer, the navy tested samples of the rum they received with this tool rather than lighting it on fire. But they continued to purchase rum at 100 proof out of tradition. It was at this point that the term “navy strength” was coined.

How did sailors drink their rum?

To combat scurvy, the navy added some water to their rum and squeezed in some lime juice. This concoction became known as grog. If you’d like to try some, check out this recipe:

Dissolve 1 oz rum and 1 oz warm water in a stainless steel shaker. Add 1 oz of lime juice, 2 oz of navy strength rum, 3 oz of water, and ice. Shake and pour in a copper mug filled with smashed ice. Garnish with a cinnamon stick and a piece of orange, or with a lime if desired.

Is all rum over 100 proof “navy strength”?

Technically manufacturers that meet the 100 proof minimum in their rum have a right to sell it as a navy strength spirit. However, the British Royal Navy bought rum of a particular style from a single merchant with the contract to sell rum to the navy. Navy rum came from a single source between the late 16th century and the end of the ration in 1970. While their rum recipe has never been made public, there are still manufacturers of navy style overproof rum on the market today!

Amazing! Where can I find navy strength rum?

Here’s what we recommend when it comes to the navy strength stuff:

Pusser's Rum Black Label: Gunpowder Proof ($35)

Pusser’s founder acquired the rights to the blending information from the British Admiralty and founded this brand, ensuring that it’s styled just like the original. It’s 54% alcohol volume though, which is just a little bit short of the 57% standard of the old tradition.

Rumbullion! Navy Strength ($70)

Many believe that the word rum is a shortened version of the word rumbullion, which is old English for noisy and uncontrollable. You’ll taste some lovely notes of vanilla, clove, and other spices in this one. But watch out! It comes bottled 114 proof, which meets the 57% minimum and would pass the old ignition test.

Black Tot 'Last Consignment' British Royal Naval Rum ($1,000)

This rum actually comes from the last existing kegs of British Royal Navy rum! You can’t get more authentic than that, although it’ll definitely cost you. Some say that its flavor gives them a chocolatey impression.