I’ve written before (like here and here and here) about the historic gunpowder proof test. (Recap: accounts from pre-hydrometer days in the 17th and 18th centuries suggest that sailors at sea worried that their daily rum tot had been watered down tested it by mixing it with gunpowder to see if it would burn. If it didn’t, it was below proof and thought to have been adulterated.)
In theory, 50% alcohol is the dividing line — the thought being that the water predominant in lower proof spirits would leach out the potassium from the potassium nitrate and render the powder inert. (At this juncture I won’t get into a lengthy discussion about alcohol by weight vs. alcohol by volume, but suffice it to say that’s been taken into consideration.)
Anything less than 50 percent was considered “below proof” — as in, it wasn’t proven. (Purser gets tossed overboard.) I’ve done demos with black powder and liquors for several groups, and in further tests on my own, and the one constant I’ve noticed is inconsistency. Sometimes a low proof spirit will flare. Sometimes a high proof spirit won’t.
So I invited a brain trust of writers and bartenders over to the house last week to help me figure out what was going on.
We started the test with the highest proof spirits and worked downward. Actually, we started by drinking gunpowder Manhattans, made with Smoke and Oakum gunpowder-infused rum and some smoky lapsong souchong tea syrup. It’s my understanding that one should never experiment with liquor, gunpowder, and matches, especially indoors, unless you’ve been drinking first.
Anyway. Gunpowder mixed with Everclear (190 proof) and Lemon Hart (151 proof) flared up reliably and quickly. But then the outcomes got all vague and flukey — some liquors at 100 and 114 proof flared up. Another at 110 did not. (I think. I wasn’t keeping tidy notes.)
Then I tried sloe gin (54 proof) just for the hell of it, and after applying a blow torch to it for a bit, the powder flared. Whatever. No rhyme or reason. Results were, as usual, all over the map. And I have to believe that historic conditions on board a lurching, filthy ship were much less controlled than in my living room.
The brain trust was very helpful, however, in enumerating an ungodly number of variables that could affect the test results. Among them:
Type of gunpowder. I assumed that historic black powder had to be used, which I tracked down. But did the original sailors use fine-grained musket powder or coarse-grained cannon powder? We were using musket powder. Perhaps the results would change with cannon powder.
Humidity. We tested on a fairly humid day in New Orleans, so that could explain why some results were different than in Maine, or in an air-conditioned hotel ballroom. But not the internal inconsistencies of the night's tests. And wouldn’t a test in the tropics on board a ship be pretty damp? Not so sure if this variable matters much.
Quantity of spirit used to dampen the gunpowder. Most accounts I’ve seen say that the grains of gunpowder were dampened with spirits. But how dampened? In most tests I used 10 drops per quarter-teaspoon of powder. But that was purely arbitrary. I probably should try other ratios and see if that has an effect.
Type of liquor. Do brown spirits affect powder differently than clear spirits? Maybe the additional cogeners are having an affect on the powder. Next time: try diluting Everclear with water to various proofs to control that variable. (Thanks to Brett Martin for that one.)
Method of igniting. We mostly used a $3 charcoal starter, but I also tried a creme brulee torch. (Note: don’t use your creme brulee torch. The gunpowder blows the igniter into a state of permanent paralysis.) Of course, neither were available in the 18th century — maybe a flint was used? Or a fuse of some sort made with hot-burning sulfur. Next time, I'll try different ignition methods. (Thanks Kimberly Patton-Bragg.)
Soaking time. I haven’t seen any account that reports how long the powder was dampened before flame was applied. Perhaps the original test involved drying the gunpowder after soaking it? I’ll give that a shot next.
So my lofty goal to solve the enigma of the gunpowder test was far from achieved. If anything, the night marked one step forward, ten steps back. I’ve now got a lengthy list of additional questions to consider. I was hoping to either figure it out, or dismiss the test as a romantic fiction.
Neither happened.
But the brimstoney gunpowder Manhattan? That’s a keeper. So the evening wasn’t a total waste.