Post #715309 by Limbo Lizard on Tue, Apr 29, 2014 1:42 PM

Not to disparage the effort at all, but I can't buy this alternative theory of the "gunpowder proof test" as a test of the quality of the powder, rather than a test of whether the rum strength exceeds an approximate threshold.

AceExplorer is correct,... the saltpeter is the oxidizing agent, not atmospheric oxygen around the grains. Also correct about grain size: musket powder had smaller grain size, for a faster burn/explosion. Cannon powder was "slower" large grains, to keep from blowing the cannon apart. Also, proportions of saltpeter, charcoal and sulfur varied, depending on the intended use. As an old chemistry buff (made black powder, too, back in junior high, early '70s), I don't think any shipboard 18th or 19th century field test with 114° rum would render useful information about plausible variations in the gunpowder.

The analysis seems to be saying that saltpeter will not dissolve well in high-proof (114°, 57% abv) alcohol, but that the charcoal and sulfur will(?). In fact, sulfur and charcoal are not soluble in water, pure alcohol, or any mixture of them. Saltpeter is not soluble in pure alcohol, but it will dissolve in water, and it will dissolve into the water component of rum. If the gunpowder was wet with water or rum, then allowed to dry, it would simply be... gunpowder. Just like before, and of course it will ignite. This would "test" nothing.

Descriptions of the "gunpowder proof test" seem to involve dampening the powder with the spirit, though, not trying to dissolve it. Dampening with water was also used during gunpowder manufacture, to keep it from igniting, and to make the soluble saltpeter more thoroughly 'infuse' and coat the charcoal and sulfur particles. It is far more plausible that the "test" was of the water content of the rum. Too much water in the rum would render the dampened powder unable to ignite. It wouldn't be an exact quantitative measure, and temperature and humidity would affect the result, especially near the burn/not burn threshold. But sailors were not likely worried that the 114° rum had been cut to 111°, or even 101°, but to well under that.

Wayne Curtis, author of And a Bottle of Rum, has experimented with the "gunpowder proof test" several times, with inconsistent results. I think much of the inconsistency comes from methodology - not controlling variables, etc. If he ever visits this again, I hope he includes someone with a chemistry background, who might contribute some "scientific rigor".

"The rum's the thing..."

[ Edited by: Limbo Lizard 2014-04-29 13:46 ]