Yellow Prussiate of Potash

I was in a restaurant last Sunday and was given one of those two-fer packets, with salt in one side and pepper in the other.

Both sides listed ingredients. The Pepper side contained “Pepper” (Not even “ground black pepper”. You’d think they’d jazz it up a little).

The Salt side contained Salt, Potassium Iodide, and Yellow Prussiate of Potash.

Really. It reads as if Joseph Priestly wrote their label. Who uses terminology like that today, especially right after “Potassium Iodide”?

I understand the Salt part (although why not “sodium chloride”, to keep up the chemical standard?) And the Potassium Iodide is clearly there because it’s an added nutrient – they’re giving you iodized salt.

I know they also sometimes add something to keep salt from sticking together, especially in humid weather. But why call it by such an archaic name?

It turns out that Yellow Prussiate of Potash is actually Potassium Ferrocyanide, a chemical I fondly recall from my old Chemistry kits. standard experiment was mixing Potassium or Sodium Ferrocyanide with Ferric Ammonium Sulfate to precipitate Prussian Blue. There were other color-changing reactions, too.

Potassium Ferrocyanide is indeed an anti-caking agent, so it was certainly added for that reason. I figure that the ancient chemical name was used because if they called it “Potassium Ferrocyanide”, too many people would look at it and say “There’s CYANIDE in my salt???!!”

But apparently not enough people remember Prussic Acid to be freaked out by Yellow Prussiate of Potash.

Weird sidelight – it turns out that I’ve been looking for Potassium Ferrocyanide for a mixture i want to make up at work. For some reason, there’s a problem getting this stuff – I still haven’t got the bottle I ordered through our company’s purchasing system. But, heck, this is a pretty safe and standard chemical, I figured, so I ordered some through Amazon.

well, it still took a long time, but I finally got it. It came in a package that originated in Russia, and it had my wife trying to figure out what I’d bought from there, festooned with Russian stamps.

Does anybody know why you apparently can’t get Potassium Ferrocyanide from American suppliers, and it takes a long time to come in from Russia? I still haven’t got the stuff i ordered at work. Apparently salt packagers have no problem getting it. Maybe I should have ordered Yellow Prussiate of Potash instead.

Russian cyberbusinessmen (an oxymoron to be sure) have taken over the historic King of Prussia’s castle, the blocks of which were carved from Yellow Prussiate of Potash.

Political prisoners break down the castle walls with picks and shovels. The old, infirm prisoners sweep the yard and package the sweepings into old opium bottles, to be sold over the Internet.


Prussic acid is especially dangerous if you’re a heartbroken young girl in a 19th century novel.


As an aside, those little packets of “100% Parmesan Cheese” you get from the pizza place contain a different anti-caking agent: cellulose (sawdust/wood).

Which is good, because we all probably need a little extra fiber in our diet.

We had a discussion about this a few years ago because I objected to Kraft labeling their grated Parmesan as “100%” when it contained cellulose. Many people thought it was OK since the cellulose was a minor additive and not an ingredient. I checked their current can in my fridge and they no longer have “100% cheese” on the label. So I was right and they caved.

yeah, they wouldn’t dare list anything containing the term “cyanide” on the ingredients.

We all live in a Yellow Prussiate of Potash
Yellow Prussiate of Potash
Yellow Prussiate of Potash

(I’unno, I’m not feelin’ it.)

It doesn’t work with Itsy Bitsy Teeny Weeny Yellow Prussiate of Potash, either.

Watch out where the huskies go,
and don’t you eat that yellow prussiate of potash.

That’s not the way food works. You add organic cyanide, label it as gluten free, triple the price, and it will outsell the non-lethal salt.

That is extraordinarily cynical.

I like your style. :wink:

They call me Mellow Yellow (Prussiate of Potash)

But I always thought that potassium ferrocyanate was blue (Prussian blue, in fact). Back in the 40s when I was a kid chemistry sets had the sodium salt and there was an experiment to make Prussian blue by mixing KCl with it.

Nowadays chemistry sets have been tamed to the point of being totally uninteresting.


It probably depends on the number of electrons on the ferrous atom.

Like cuprous sulfate and cupric sulfate.

Or something like that. My chemistry days were last century, and I’ve only had three cups of coffee.


No – Potassium ferrocyandide is yellow (I know, I just mixed up a solution of it Friday). The “Chemical magic” part came when you mixed that yellowish ferrocyanide solution with colorless Ferric Ammonium Sulfate solution and got that bright Prussian Blue. A fondly remembered part of my nerdish childhood