The British Navy’s Rum Vatting System: An inside look

As the 50th anniversary of Black Tot Day approaches, interest in all things British Navy rum is rising. A topic rarely discussed is how and where the navy actually blended their rum.

Britain’s navy had a series of victualling (pronounced “vitalling”) yards in various places in the U.K., and elsewhere around the globe where they had bases. Victualling yards are supply depots and factories for provisioning ships. Meat, cheese, biscuits, candles, clothing, rum, and just about any consumable item you can imagine came via the victualling yards.

The largest and most important victualling yard was the Royal Victoria Victualling Yard in London’s Deptford neighborhood. The navy blended prodigious amounts of rum within the compound, and at smaller victualling yards in Portsmouth and Plymouth. There’s also evidence the navy blended rums at a victualling yard in the South Pacific, but details are far complete.

Now, about the rum blending itself. Several newspaper reports and periodicals provide basic details of how it happened. The first is from 1900:[i]

The rum is purchased by the Government at the prodigious strength of 40 degrees above proof, and this has to be reduced to 4.5 under proof. This process is effected in thirty-two vats of enormous size, housed in specially constructed buildings along the riverside. They have a total capacity of 230,000 gallons, the largest bolding 32,817 gallons. This vat is two-thirds the size of the famous Heidelberg Tun, and, having regard to the far greater potency of its contents, I am not sure that it is not the more impressive sight. From the vats the rum is run into casks, ready for despatch to all parts of the world, and while witnessing this operation at a discreet distance I could readily believe that to the midst of this immense quantity of fiery spirit one could easily become inebriated without a drop of the liquid passing the lips

Other texts indicate some of those 32 vats were dedicated for use as starting vats, into which rum casks were emptied. Others were issuing vats, kept at “4.5 degrees under proof”. That phrase, “4.5 under proof” was the common way of the time to designation alcoholic strength. It’s the equivalent of 54.5 percent ABV. The issuing vats were the final stop for rum as it proceeded though the vats.

Small Deptford Victualling Yard vats

Another text provides a bit more information about the size of Deptford’s vats, and includes an amusing anecdote:[ii]

The vats at Deptford vary in size from 4600 gallons to 32,000 gallons. There was for a long time a legend which said that a certain small terrier which had mysteriously disappeared was last seen alive on the edge of one of the vats. But when in the course of time the vat was emptied for examination and cleaning, no skeleton was found there. But relics which told a much more pathetic tale were discovered. There were a large number of bottles at the bottom of the vat, to which were attached pieces of string! Ingenious and thirsty workmen in the yard bad been in the habit of getting their grog by illicit means, and had been forced to abandon their attempts occasionally when detection seemed near.

Appendix I from the Nelson’s Blood book[iii] contains an excerpt from an 1888 text with yet more details on the vatting setup, and references the issuing vats mentioned previously:

The Rum is started into the vats which are all connected one with the other, although any one or more can be shut off, with such a quantity of water as will, it is estimated, reduce it as nearly as possible to issuing strength (4.5 under Proof) but as it would be difficult to hit off this strength precisely in all the 32 vats, two of them, (Nos 1 and 2), containing 17,960 and 17,820 gallons respectively, are appropriated as issuing vats in which the spirit is always kept at the precise issuing strength.

How long did rum flow in the vats? A short excerpt from an 1876 article provides some interesting insights:[iv]

As it arrives from the contractors it is poured into open vats, and allowed to flow from vat to vat for a period of two years. The result is that the hot spirit or volatile is discharged and thrown off. The rum, on being issued to the service, is ripe, mellow, and aged, the action on the human system being altogether different to the effect produced by fiery spirits.

Two important things jump out from this short passage. First, the rum (at least at that time) spent around two years mellowing in the vatting system. Second, that the vats were open vats, i.e. without a cover. This would assuredly lead to significant loss of alcoholic strength. On the other hand, the rum makers needed to reduce the strength anyhow.

Both are fascinating observations that lead to many more questions. I’m always looking for additional documents that shed further light on this.

One of the remaining rum stores at Deptford

Unfortunately, existing records are surprisingly sparse about the navy’s rum vatting procedures used at Deptford and elsewhere. I and other historians have speculated on how the vats were arranged and operated. Unfortunately, pictures of the vats are also exceedingly rare. Nonetheless, I believe that in time, and with access to the right archival sources, we may just learn a great deal more about this fascination corner of British Navy rum history.


[i] Sheffield Weekly Telegraph 03 November 1900

[ii] Hampshire Chronicle 23 June 1906

[iii] James Pack, Nelson’s Blood: The Story of Naval Rum; 1982

[iv] Northern Whig 28 September 1876