# What the hell is "Potash?"
**URL:** https://boards.straightdope.com/t/what-the-hell-is-potash/1013436
**Category:** Factual Questions
**Created:** [January 26, 2025, 4:25pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436 "2025-01-26T16:25:52Z")
**Posts on this page:** 16
**Page:** 8
### Author:  [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)
#### Post date: [February 6, 2025, 1:56pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/141 "2025-02-06T13:56:49Z")
As well, some metals we think of as strong become very brittle at cryogenic temperatures. Brittle = prone to shattering or cracking under even tiny stress.
Breaking that mirror would be very expensive very bad luck
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### Author:  [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)
#### Post date: [February 6, 2025, 9:05pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/142 "2025-02-06T21:05:03Z")
> [@purplehorseshoe](#):
>
> What does that last part mean in the context of mirrors and lenses?
The main thing is that it has very low thermal expansion when it’s that cold. Note that this is about the _rate_ of expansion, not the absolute amount. The telescope is always kept cold, but there are still small thermal variations. So having a small rate (coefficient) is valuable to keep the mirrors from distorting. And beryllium has the unusual property that its rate of expansion is very small at that temperature.
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### Author:  [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)
#### Post date: [February 8, 2025, 1:09am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/143 "2025-02-08T01:09:42Z")
Thank you. This is an example of the clear scientific explanations I get on these boards. I appreciate it.
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### Author:  [@ZurBob](https://boards.straightdope.com/u/ZurBob)
#### Post date: [February 16, 2025, 3:12am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/144 "2025-02-16T03:12:00Z")
> [@TriPolar](#):
>
> Not exactly. **Potash provided the potassium.** Dung-urine beds, along with **old rotting timbers were used as the source of nitrogen** … (bolding mine)
Wood ash is not the primary donor of potassium. It’s function is essentially as an alkaline moderator of Ph, reducing the acidic environment created by bacterial activity in the ammonia/nitrogen/nitr_ **i** _te/nitr_ **a** _te conversion of urine and manure, the PRIMARY source(s) of potassium and nitrogen in niter beds. Yes, wood ash contributes, but its mass effect is minimal compared to urine and manure and possesses NO nitrogen.
However, wood ash is also used when extracting (leaching) the final mass of nitrates with water at the end of the procedure that takes 1-2 years for completion. At this point it acts as a potassium donor for any un-attached nitrites, but the bulk of KNO3 has already been produced.
But reliance on wood ash to provide all the necessary potassium in this entire process would require such a huge amount it would prove toxic to the bacteria, due to the extreme alkalinity it would create…not to mention your stated scarcity of such.
“old rotting timbers” would provide nothing to this process except un-necessary carbon and _ **an** _erobic bacteria.
> [@TriPolar](#):
>
> Potassium Nitrate was produced from those ingredients, which was used in the manufacture of black powder.
Of course, potassium nitrate is used…as is charcoal. But one would not say that _trees_ (the precursor of charcoal) are used in the manufacture of gunpowder
For an interesting read, goto: . [Joseph Leconte, 1823-1901. Instructions for the Manufacture of Saltpetre](https://docsouth.unc.edu/imls/lecontesalt/leconte.html) A Civil War era rebel’s guide (published in 1862) for producing KNO3.
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### Author:  [@notfrommensa](https://boards.straightdope.com/u/notfrommensa)
#### Post date: [February 16, 2025, 4:39am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/145 "2025-02-16T04:39:39Z")
My balderdash definition for “potash” would be medical marijuana for hemorrhoids
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### Author:  [@ZurBob](https://boards.straightdope.com/u/ZurBob)
#### Post date: [February 16, 2025, 4:55am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/146 "2025-02-16T04:55:22Z")
I shudder to think how it would be administered.
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [February 16, 2025, 5:15am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/147 "2025-02-16T05:15:18Z")
> [@ZurBob](#):
>
> “old rotting timbers” would provide nothing to this process except un-necessary carbon and _ **an** _erobic bacteria.
Old rotting timbers provide a source of nitrates, not potassium. Dung and urine beds are used because of the plentiful supply of those materials but rotting timbers alone can be used
> [@ZurBob](#):
>
> Of course, potassium nitrate is used…as is charcoal. But one would not say that _trees_ (the precursor of charcoal) are used in the manufacture of gunpowder
Right, no one would say that because it doesn’t make sense. Gunpowder is made from three primary ingredients, and _trees_ isn’t one of them while potassium nitrate is.
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### Author:  [@ZurBob](https://boards.straightdope.com/u/ZurBob)
#### Post date: [February 16, 2025, 6:30am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/148 "2025-02-16T06:30:21Z")
> [@TriPolar](#):
>
> Old rotting timbers provide a source of nitrates, not potassium. Dung and urine beds are used because of the plentiful supply of those materials but rotting timbers alone can be used
The rotting of timber (essentially carbon) has a net **consumption** of nitrates, it doesn’t produce them, and the biological process involved in rotting timbers primarily involves **an** erobic bacteria. Niter bed production of nitrates (KNO3) require **a** erobic bacterial action. Rotting logs are a lose-lose proposition so, no, they definitely could not be used exclusively as a replacement for urine and manure. Best to keep them out of the equation altogether. **I certainly never said rotting logs provided potassium.**
> [@TriPolar](#):
>
> Right, no one would say that because it doesn’t make sense. Gunpowder is made from three primary ingredients, and _trees_ isn’t one of them while potassium nitrate is.
Likewise, it doesn’t make sense to say, as you did, that wood ash (potash) is used for such. Potash is not one of the three primary ingredients of gunpowder either. Remember my “nitpick” way upthread? I stated that wood ash wasn’t used in the manufacture of gunpowder **per se** , but rather, it was used in the production of KNO3. That was the inception of this whole conversation!
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [February 16, 2025, 12:02pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/149 "2025-02-16T12:02:13Z")
> [@ZurBob](#):
>
> **I certainly never said rotting logs provided potassium.**
And I never said rotting logs were used. Do you know what timbers are?
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [February 16, 2025, 12:03pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/150 "2025-02-16T12:03:32Z")
> [@ZurBob](#):
>
> I stated that wood ash wasn’t used in the manufacture of gunpowder **per se** , but rather, it was used in the production of KNO3.
Exactly what I said.
> [@TriPolar](#):
>
> Potassium Nitrate was produced from those ingredients, which was used in the manufacture of black powder.
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### Author:  [@ZurBob](https://boards.straightdope.com/u/ZurBob)
#### Post date: [February 17, 2025, 1:32am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/151 "2025-02-17T01:32:51Z")
> [@TriPolar](#):
>
> And I never said rotting logs were used. Do you know what timbers are?
It’s obvious that we’ve not been on the same page here, and apparently you **really** have a need for the last word, so here’s your chance.
Please enlighten me as to the difference between rotten log and rotten timber.
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### Author:  [@TriPolar](https://boards.straightdope.com/u/TriPolar)
#### Post date: [February 17, 2025, 12:50pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/152 "2025-02-17T12:50:29Z")
I accept your apology and since your plea for information sounds desperate I’ll provide it.
Rotting logs are trees that fall over in the forest. Timbers are made from logs but are used as components in structures like houses and barns. They aren’t lying on the wet forest floor like a log where they slowly decay. Instead they’re use in structure keeps them off the ground and provides plenty of exposure to air. There they become infested with insect larva and bacteria that use aerobic action to produce nitrates. The cellars of timber frame structures are often full of decaying wood and larva bodies which are full of nitrates.
The need for potassium nitrate in France during their endless wars with England became so great they enacted a law allowing the government to seize peoples homes and farm structures to be used to make nitrate for gunpowder. Since these timbers have been rotting for years already, possibly a century or more they are immediately ready to use instead of waiting nearly a year for nitrates to form in dung piles.
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### Author:  [@Irishman](https://boards.straightdope.com/u/Irishman)
#### Post date: [February 18, 2025, 9:29pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/153 "2025-02-18T21:29:12Z")
> [@RickJay](#):
>
> It’s an objectively better word than “potassium.”
Yeah, pot-ass-ium is a lousy name.
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### Author:  [@Irishman](https://boards.straightdope.com/u/Irishman)
#### Post date: [February 19, 2025, 1:02pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/154 "2025-02-19T13:02:04Z")
> [@TriPolar](#):
>
> Since these timbers have been rotting for years already, possibly a century or more they are immediately ready to use instead of waiting nearly a year for nitrates to form in dung piles.
Interesting.
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### Author:  [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)
#### Post date: [March 11, 2025, 2:33am UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/155 "2025-03-11T02:33:51Z")
Here is a video. FWIW I am not posting it to be political but it seems to answer the OP.
[ ](https://www.youtube.com/watch?v=gXy4kQc3uUg)
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### Author:  [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)
#### Post date: [July 16, 2025, 7:52pm UTC](https://boards.straightdope.com/t/what-the-hell-is-potash/1013436/156 "2025-07-16T19:52:52Z")
> [@leahcim](#):
>
> At some point during a family road trip, we went past [Kalium Rd](https://www.google.com/maps/place/Kalium+Rd,+Pense+No.+160,+SK,+Canada/@50.408013,-105.2190969,17z/data=!3m1!4b1!4m10!1m2!2m1!1sKalium+Road!3m6!1s0x531bfcb7920fa29b:0x3b8c3a3190b0b0f3!8m2!3d50.4080131!4d-105.214226!15sCgtLYWxpdW0gUm9hZJIBBXJvdXRl4AEA!16s%2Fg%2F1ydnytqv3?entry=ttu&g_ep=EgoyMDI1MDEyMi4wIKXMDSoASAFQAw%3D%3D), named after the Potash industry in the area.
Driven past it many a time.
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