The basic ingredients of black gunpowder are simple- saltpeter for the oxygen supply, charcoal for the fuel, and sulfur to encourage combustion.
In the old days the primary source for saltpeter was a "nitre bed", where multi-sourced manures, urines, straw and other organic material were fermented, with the resulting drainage boiled down and purified to get more or less pure potassium nitrate. A nitre bed may be seen at George Washington's home in Virginia.
Charcoal is an ancient fuel resource, developed when humans first began using heat to smelt and shape metals. The traditional method for making charcoal started with a mound of dried hardwood carefully stacked to allow air circulation, then covered with turf and soil. Holes were opened in the ground level sides of the "rick", and vent holes opened in the top. Small fires built in the ground level holes had to be carefully tended so they supplied enough heat to drive all of the volatiles off but did not set fire to the pile. Ricks required 24 hours a day attention to keep the fires burning just right, using dampers at top and bottom to regulate flow, this for several days. Charcoal making was an intensive and important business.
No sulfur sources existed in Colonial America; the nearest sources were volcanic islands of the Caribbean. There was a smuggling trade from there to the colonies. France assisted in this trade. At that time, France would do anything to annoy England. One of the major contributions to our revolution was the powder supplied by France after the big win at Saratoga.
