How is it, that two seemingly identical canisters of Morton potassium-chloride salt, can taste quite so very different? (See answer in TL;DR at bottom.)
For, upon switching from a bag of Morton potassium chloride purchased at a recent date, to another bag containing the contents of a seemingly identical canister purchased at a slightly later date, the soups that I make using this salt now taste grossly reminiscent of ocean salt2, 4… (And, I’ve tried the identical recipe of 1 tsp Kosher sodium-chloride salt to 1/4 tsp potassium-chloride salt to a pint of the very same cold, plain soup, and the difference is consistent.)
The ingredient lists on the two salts are the same… with additives of fumaric acid, calcium phosphate1, and silicon dioxide…
Is it possible that the second container of potassium salt came from a batch that received a much greater dose of one or more of those additives?
You’d think that an industrial salt company like Morton would be very consistent and standardized in producing a consistently composed product–especially an inorganic one like salt, which does not depend upon any irregularities of organic agriculture and livestock-raising (regardless of whether or not those life-based, organic products are certified as “Organic” (with a Capital “O”).
Is it possible that they just changed their recipe or process?
Anyhow, I also find it strange that a salt should require three additives for doing nothing more than simply serving the function of anti-caking. Perhaps, one/some of these other chemicals are actually not additives at all, but some other chemical(s) that naturally co-occur with the potassium chloride in whatever source Morton buys or harvests from, and is/are simply left in to some extent by virtue of a less costly process?
This could perhaps explain how, even just a different batch of raw material could, through an effectively identical production process, precipitate into a product salt that contains less/more of some un-removed components.
(For one instance, if the potassium salt was derived from bone-meal, which naturally contains significant amounts of calcium phosphate, then I can see how a process which does not totally remove this co-occurring chemical could produce a product salt of varying concentrations of calcium phosphate, if the supply of animal bone meal also varied in its concentration of this chemical likewise-regularly.)
2020/6/13 Saterday, early-evening;
written whilst savoring one of the last good-tasting bottles of cold, plain soup that I [would] be able to make for a while until I [could] go into a town and hopefully find a purer source of my potassium-salt.
(Although, judging by how the second bag of potassium salt reeks when opened (with a sharp, burning smell), I’d guess that the culprit in this second batch is actually the fumaric acid3, the only possibly volatile chemical of the three extra ingredients/components. And, if fumaric acid is truly volatile, then this would also provide another possible explanation for how, even if all three of these extra components truly are ingredients, intentionally added by Morton for whatever purpose as part of a standardized recipe, a second batch of salt could contain more of this compound. For, perhaps the first canister had simply been sitting in storage / on the shelf for a very long time and most of the fumaric acid had already evaporated8, while the second one was perhaps from a very current batch, and freshly restocked.5
(So, heh, it looks like I may have even just answered my own question, out here in the woods with no internet  and only a pen and paper at my service. (As well as, a brain and nervous system, well stocked, with its main energetic currencies, of sodium and potassium.)
(And of course, the culprit cannot be the silicon dioxide, which is just simply the chemical formula, for the biologically-inert substance that is the main component of most ocean sands.6)
– slightly-later- evening
Interestingly, the name of this compound in the ingredients list is, specifically, mono-calcium phosphate, even though, by the pure compound’s chemical formula, one would perhaps expect the name to instead be, tri-calcium di-phosphate. Does this mean that what Morton actually adds to their salt is calcium (mono)-hydrogen phosphate?
Which, if you’ve ever accidentally (or intentionally!) tasted while swimming in the ocean, you might agree, isn’t the most pleasant experience, to say the least! (And to say the most, is nauseatingly gross!!) 😀
Apparently, fumaric acid is quite common in nature, so this might explain why the newer, smellier salt reminded me of raw ocean salt–which maybe contains a fair bit of fumaric acid as well!
Though, come to think of it, this could also be the very reason that Morton chose to add this particular doubtfully-anticaking substance to this kalium/potassium-based, chloride-salt, which is in fact labeled as a (natrium/sodium) salt substitute. For, pure potassium chloride tastes very different, from typical, mostly-sodium-based, salts.
Or, another possible explanation–also based on the fumaric acid- volatility theory–for how these two batches of salts could have ended up with such different concentrations, even before making it to the shelf and then to my air-tight freezer bags, is that, perhaps, even though produced by a fairly standardized large-scale-production process, one batch, got significantly hotter, than the other, and so lost more of what perhaps started as an identically-mixed recipe, somewhere on the production line.7
That is… unless the grain/fine-ness/shape, that it occurs as what I assume is an anti-caking-ly- functioning additive in this product, affects (possible?) taste?
(And–at the least, if this fumaric acid theory is the case–one possible remedy to this culinary conundrum I have found myself in, rather than going into a nearby town where I know I can find an additive-free, pure, brand of potassium-chloride salt called NuSalt, could be to simply cook the fumaric acid out.) ((And, cooking the dry salt would of course leave the salt itself, which is non-volatile, unchanged.)) (((With the one possible exception being any calcium hydrogen phosphate present–which, just like baking soda, a. k. a. sodium hydrogen carbonate, could perhaps decompose, a. k. a. break down due to influence of being heated, into some likewise gaseous products.)))
A true possibility, given that Morton’s small salt canisters are not air-tight. For, (now that I am actually typing this into an electronic typewriter in a town), given, how I can even smell the acid-burny-smell of what I assume is fumaric acid, through the closed lid of this brand-new shaker of Morton Salt Substitute, right-here, right-now; this theory does indeed seem to hold some perhaps quite non-volatile ground. 😛
TL;DR: Morton apparently adds Fumaric Acid to mimic some ocean-ey flavors/odors in this otherwise very not-ocean-y, completely sodium deficient, salt.