Fernando, perfectly written and well illustrated as always and I always enjoy your analogies!! good points on the 'omelette' making as in gun powder making and right, the other two components were quite necessary as well.
On the dampness issue, I thought to look into how in the world powder was dealt with in the days of 'fighting sail'. Obviously at sea, there was a 'bit' of dampness around
Apparently there were individuals assigned to keep powder viable. One source says the men in these areas wore special footwear and there were curtains kept moist to avoid sparks. Surprisingly it is noted the magazine was usually below water line, so further puzzling how it could be kept dry.
In any case, the keepers of the powder apparently were charged with sifting it and remixing it for distribution to the 'powder monkey's (young boys carrying it to gunners).
Perhaps failure to properly sift and remix powder supplies were key in the poor quality of the Mexican powder?
If the Dupont powder was so great, would it not be susceptible to moisture damage?
Yulzari thank you again for these further insights, and the note that Chile was a source for the saltpeter used in Mexico. It was cheap and there was of course notable volume of its production. The constant maritime activity from there seems well understood so inclusion of the saltpeter would be expected.
I admit I am still unclear on the differences in saltpeter, between sodium and potassium nitrates. It seems that both of these compounds are derived from bat guano. The only notable difference seems to be that the 'potassium' version is less 'hygroscopic' (susceptible to moisture effects) if I have understood correctly.
Returning to the Alamo for a moment, in a touch of irony, one defender was killed as he ran toward the powder magazine with a torch. The miserably inadequate powder he hoped would take out as many attacking Mexicans as possible.
On the US powder production, it does appear that guano was indeed used broadly for saltpeter up to and including the Civil War, however I have wondered if the Dupont powder of such noted high quality was in fact using the 'French' process. The Confederate forces had many mills and all seem to have used either guano or other means of saltpeter production. There is some mention of use of urine, but unclear how much used that instead of guano etc.