An interesting section of Blood Meridian (1985) by Cormac McCarthy has the gang of "Indian fighters" surrounded and out of powder, so one of them manages to make it from scratch, making charcoal from wood, saltpeter from bat guano and finding sulfur in a volcanic area, but the final step has them urinating on the mixture and then drying it in the sun. I understand that urine can in fact be a source of nitrates but given that they already had saltpeter, I am puzzled. At the same time, I understand that gunpowder is made wet to form larger grains but this can be done with water (I think), which they had access to.

The gunpowder was first dry so urinating on it was not for safety; it may have been an old-fashioned idea about how to make gunpowder and an unnecessary step or at least water would work as well for "corning" – making granules from it.

  • $\begingroup$ Yes, it can be done with water... but in the book, is water scarce? $\endgroup$ Sep 20, 2018 at 3:44
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    $\begingroup$ Forget the grains. Gunpowder is made wet so as not to explode during production. $\endgroup$ Sep 20, 2018 at 5:15
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    $\begingroup$ firstly, what Ivan says, and secondly, salpeter dissolves in water and after drying coats the other particles, which makes for a much higher contact area and greatly increases explosivity. If you just mix the dry stuff, your bullets will limp out of the barrel like dead fish. $\endgroup$
    – Karl
    Sep 20, 2018 at 18:52
  • $\begingroup$ and yes, they urinate on it to make it sound more tough. ;-) $\endgroup$
    – Karl
    Sep 20, 2018 at 18:55
  • $\begingroup$ @DrMoishePippik: yes, water was available and used in an earlier stage of the process -- there was a stream. They urinated on the final mixture, spread it on rocks to dry and were in a desperate race for it to dry in time which it did. So the urine stage if unnecessary put them all in jeopardy -- clearly The Judge thought urine was needed to make usable gunpowder. $\endgroup$
    – releseabe
    Apr 3, 2021 at 13:12

2 Answers 2


Classic black gunpowder was often produced by a wet mixing process, after which powder was dried and then ground to fine powder or grains.

The reason for it was better homogenisation of the final powder and increased powder efficiency due faster deflagration.

The urine might not be used then for being urine, but for being water based, as they could be short of water supplies, not to waste water for it.


In Literature stackexchange we have this answer which indicates firstly that urine is something that can be used and secondly that saltpeter probably can't be extracted as fast as portrayed in the story (although that may or may not be true). https://literature.stackexchange.com/questions/24314/does-blood-meridian-accurately-describe-gunpowder-manufacture


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