Can you tell if your stored salt is iodized by putting some on a potatoe and seeing if it turns slightly purple???

No. The amount of iodine in table salt is tiny.

ETA:  Federal survey data shows that most Americans have an adequate iodine level. If you are concerned, fish  and shellfish, dairy products, bread and other grain products, and eggs supply iodine as well.

it should work, add a few drops of vinegar to the salt solution.

"Test for Iodide in Table Salt" >>> (https://www.youtube.com/watch?v=8jVV0o5sl1g)

Thank you!

Dioxane reagent is available on eBay for $30...  Too much for what I want to do...


We bought a flat of salt shakers from one of the box stores and I'd like to know if the salt is iodized...

Is there an alternative way?




From Wiki for everyone interested---

Four inorganic compounds are used as iodide sources, depending on the producer: potassium iodate, potassium iodide, sodium iodate, and sodium iodide. Any of these compounds supplies the body with its iodine required for the biosynthesis of thyroxine (T4) and triiodothyronine (T3) hormones by the thyroid gland. Animals also benefit from iodine supplements, and the hydrogen iodide derivative of ethylenediamine is the main supplement to livestock feed.[4]

Salt is an effective vehicle for distributing iodine to the public because it does not spoil and is consumed in more predictable amounts than most other commodities.[citation needed] For example, the concentration of iodine in salt has gradually increased in Switzerland: 3.75 mg/kg in 1952, 7.5 mg/kg in 1962, 15 mg/kg in 1980, 20 mg/kg in 1998, and 25 mg/kg in 2014.[5] These increases were found to improve iodine status in the general Swiss population.[6]

Salt that is iodised with iodide may slowly lose its iodine content by exposure to excess air over long periods.[7]

Production[edit]

Edible salt can be iodised by spraying it with a potassium iodate or potassium iodide solution. 57 grams of potassium iodate, costing about US$1.15 (in 2006), is required to iodise a ton of salt.[1] Dextrose is added as a stabilizer to prevent potassium iodide from oxidizing and evaporating. Anti-caking agents such as calcium silicate are commonly added to table salt to prevent clumping.

I'll try this...



ETA-

Put some known iodized salt [pretty sure] and RO water in a cup to get a saturated solution...

Added some apple cider vinegar and put a thin slice of a potato into the mix.

Waiting to see if there's a color change.

Just came back and there hasn't been a change.

Need to get a known sample of iodized salt and try it...

Also make a diluted solution of potassium iodate and try that...

Try a few drops of bleach. You need elemental I2 for the color reaction.

Taste it.

Seriously.

Put a tablespoon in a cup of water.  Compare with same of pickling salt.

It will be really obvious. Iodized will taste awful.

Good ideas you 2...

I have to return to civilization in a couple days to get known iodized samples... Unless my SO can find some up here...

The extra chlorine will dissociate the sodium iodide or whatever they add to salt?

It will oxidize the iodide to iodine, that will intercalate into the starch and produce the blue color (actually, in aqueous solution is it I3-, which is an iodine molecule combined with an iodide.)  It works much better if you can put a little bit of HCl into the bleach (forms chlorine in situ).  Any acid would help, but HCl is best.
If you had some hydrophobic organic solvent which would separate from water, you could make a solution of the salt, add some bleach, then shake it. The iodine would partition into the hydrophobic layer and turn it purple.
But I am sure there is not nearly enough iodine in the salt to produce a noticeable color.  The starch would be a much better bet.
Even so, like you say, you need a know iodized salt to use as a control.

Looks like you answered his question. I'm curious if the iodide concentration in salt is high enough to get a positive starch reaction.

Question OP. Are you hoping the the salt is, or isn't iodized. I use both here at home.

Salt is so inexpensive it doesn't matter.

It's mostly an intellectual exercise.


This morning as I was in the BR, I read in Henry Hubbard's old-timey string bound  phillysopical tombe, that I found in a thrift store years ago...

"A young person working in a shop or factory---

Who spends some time outdoors...

And an HOUR a day in intellectual exercise...

Will distinguish himself in life."

Paraphrasing...

Not being a smartass, but what did the package say? If it didn't say iodized, I doubt it is.

Oh, well in that case, carry on. And good luck

No marking...

Bulk flat of salt shakers... 24 IIRC.

Odd. Many people put a little salt in their coffee when they brew it to stop some of the bitterness.

Iodized salt can be used for preserving. Based on what I remember from my middle school Chemistry class, iodine will simply evaporate if salt is heated in the oven. I may be mistaken. It's been over 30 years since that Chemistry class. LOL.
It may be worth trying. Just put iodized salt in the oven for 30 minutes, at 400 degrees. Iodine should evaporate completely, unless it's chemically bonded somehow.

damn you, arfcom!


a mixture of 1 tsp tapioca starch and 1 tsp iodized salt was prepared. mixture was disolved in 2 tblsp water, and mixed until no solid clumps remained. 4 drops 6% sodium hypoclorite was added to the mixture, and stirred.

self induced heating of the mixture was achieved by microwave radiation for 15 seconds. hydration of starch granules resulted in gel like clumps of solidified starch, but no coloration change.


so... on to the internet and
https://www.scientificamerican.com/article/bring-science-home-iodine-salt/

i havenn't tried it yet, so if someone does it, they can report here

many theories on why this happens: TLDR: the salt molecule fits into the same hole as the bitterness on your tongue and blocks it increasing the sensation of sweetness.

Or its a mind game, either way it works

I thought if it was a fine and consistent grain then it is iodized. Sea salt usually requires a grind shaker.

Thank you!  Interesting...

I'll likely do the experiment as soon as I can get some starch. In the mtns now...

coloration change as a method of testing for iodization of salt

mix
4 oz water
1 tsp h2o2
1 tsp vinegar
1 tbl spoon test salt

add, and mix in
1/4 tsp corn starch

allow mixture to sit, though coloration change to a dull purple begins immediately for iodine containing salt, but no change occured for sea salt.

edit - modification of the experiment from scientific american

nope, canning salt is the same size as regular iodized salt.

This is not correct.  Canning salt is non iodized and without caking additives.  It is just plain salt of a fine grind.  The anti caking additives can tend to turn the pickling liquid in home canned products like pickles cloudy.  Iodine can cause discoloration to the canned products.  Iodized salt can be used, however it is not ideal due to the product presentation issues.  Not a big issue for home canning, but it is a big issue for retail sales.

we were taking about the size, at least I was.

ie looks the same