Never mix alcohol and gunpowder. It makes a lousy drink, and your gunpowder gets wet and won't work.

Therefore demonstarting your alchol is less than 100 proof. What is the legion playing at drinking that kind of stuff, it might as well be fruit juice?

Knowing the old field test for alcohol levels would be useful for something, eventually. Gunpowder soaked in 100 prof alcohol still burns, any weaker it doesn't. The exicsemans test was to test it and then to add more alcohol or water as needed to get to 100 proof, and so see how much tax was due on it....