Apparently Blackbeards favourite drink was rum and gunpowder. Was gunpowder regularly consumed in the past, was it dangerous, did it add flavour? Is it still used today in food / drink?

#Was Gunpowder Regularly Consumed?

I would not go so far as to say that it was regularly consumed. But it certainly was not unheard of.

##Gunpowder and Saltpeter

Gunpowder consists of sulfur, charcoal, and saltpeter (potassium nitrate). The latter of these three had been used to cure meat since the Roman times. Reportedly, "by around 200 BC, the Romans recognized that salt from some sources contained contaminants that contributed a reddish-pink color and flavor to cured meats" [1]. This contaminant was none other than saltpeter.

By the mid-17th century saltpeter was widely used as a "relatively [available]" meat preservative [2]. At times gunpowder would be similarly used, on the basis of its saltpeter content. Rabbi Henry Cohen, writing in 1900, relates the tale of a US military expedition to confront American Indians on the frontier, as they sought to oppose the expansion of the railway onto their lands. Following a brutal battle, the American garrison's supplies began to run low. Cohen explains that after four days under siege by the Indians, "the meat [...] began to get putrid, and it was sprinkled with gunpowder, in the hope that the saltpeter in the powder would aid in preserving the meat or make it a little less unpalatable" [3]. (Alas, it was not effective). Thus there was clearly widespread knowledge of the use of saltpeter as a preservative, and under extreme circumstances, gunpowder might be used as a source thereof.

##The Link between Gunpowder and Rum

With more relevance to Blackbeard's drink, the mixture of gunpowder and rum would have been fairly well known. Not for consumption's sake, but to establish the rum's proof. Sailors would mix their rum ration with a bit of gunpowder, and expose it to a flame. If the gunpowder caught, that was said to be "100% proof" that it had not been watered down (57.15 was the necessary alcohol by volume for it to catch) [4]. That said, there's no indication Sailors mixed the two for purposes other than this.

#Gunpowder and Rum in Jamaica

However, the mixture of rum, gunpowder, and other substances does appear in various Caribbean rituals and religions, most notably in Jamaica.

The ritual consumption of rum and gunpowder stems from Tacky's rebellion of 1760. Erskine explains that Tacky's "warriors prepared for war by mixing rum with gunpowder and grave dirt," adding a bit of blood from each participant, and subsequently sharing the drink amongst one another [5].

The ritual persisted past Tacky's rebellion, and became a part of the Jamaican religion Obeah. The ritual and other elements of the religion "were passed like heirlooms between successive generations of freedom fighters." The drink marked the rebels' pledge of loyalty to one another and to their cause [6].

The tradition lasted at least until 1865, when Paul Bogle, a Baptist minister and one of Jamaica's National Heroes, performed it as part of his own freedom movement [6]. We find mention of it in British Governor Edward John Eyre's 1866 report before a royal commission. Eyre describes that after men swore an oath to the Bogle's rebellion, they were "then given each a dram of rum and gunpowder to drink" [7]. Eyre's account stems from the testimony of rural constable James Foster, who describes [7]:

Paul Bogle spoke to the men in a language I did not understand. The men then took the oath; they kissed a large book, the Bible. Paul Bogle gave each of them a dram of rum and gunpowder, which they drank. I saw the rum and powder mixed myself in a large bottle.

#Other Questions

##Was it Dangerous?

In small doses, no. However, Thomas Trotter, a British naval physician from 1779-1802, comments on the occasional consumption of gunpowder by sailors for the purpose of feigning illness [8]:

When at Plymouth in October last, a paper, taken from a sailor was put into my hand by Dr. Mein of the Caton hospital ship from which it appeared that deception was become a complete and scientific system. Among other articles to produce spitting of blood, gunpowder or salt petre is taken in large doses; haemoptysis quickly follows from the blood being overcharged with oxygene gas which these ingredients readily afford.

##What was its Flavour?

Charcoal tastes bad (multiple pediatric studies of activated charcoal indicate children often refuse it) [9]. Sulfur is flavourless. Saltpeter has a "cooling, saline pungent taste" [10]. Thus, the combination of all three would not taste particularly good, but any flavour would likely be drowned out by the rum.

Citations

Bedale W, Sindelar JJ, Milkowski AL. Dietary nitrate and nitrite: Benefits, risks, and evolving perceptions. Meat science. 2016 Oct 1;120:85-92.
Edwards ME. Virginia Ham: The Local and Global of Colonial Foodways. Food and Foodways. 2011 Feb 9;19(1-2):56-73.
Cohen H. A Brave Frontiersman. Publications of the American Jewish Historical Society. 1900 Jan 1(8):59-74.
Rogers A. Proof: the science of booze. Houghton Mifflin Harcourt; 2014 May 27.
Erskine N. The roots of rebellion and Rasta theology in Jamaica. Black Theology. 2007 Feb 1;5(1):104-25.
Barima KB. Cutting across space and time: Obeah's service to Jamaica's freedom struggle in slavery and emancipation. Journal of Pan African Studies. 2016 Jul 1;9(4):16-32.
Papers Laid before the Royal Comission of Inquiry by Governer Eyre. British Parliamentary Papers. 1866.
Porter IA. Thomas Trotter, MD, Naval Physician. Medical history. 1963 Apr;7(2):154-2.
Skokan EG, Junkins EP, Corneli HM, Schunk JE. Taste test: children rate flavoring agents used with activated charcoal. Archives of pediatrics & adolescent medicine. 2001 Jun 1;155(6):683-6.
National Center for Biotechnology Information. PubChem Compound Database; CID=24434, https://pubchem.ncbi.nlm.nih.gov/compound/24434.