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Simon Quellen Field’s book Why There’s Antifreeze in Your Toothpaste is a fascinating read. I found the part on adding iodine to table salt particularly interesting because while it seems like it should be a simple procedure, it’s actually far more complicated than you’d imagine.
Let’s back up a bit. So, why is there iodine in table salt anyway? In the early 20th century, researchers figured out that if they added iodine to peoples’ diets it would prevent goiters. And the simplest way to do this seemed to be to add the iodine to salt, which was already being used in a variety of foods. By mid-century, most households used iodized salt, and goiters were basically a thing of the past. But the solution wasn’t as simple as it sounds.
Here’s the problem. The cheapest and most common form of iodine is (1) potassium iodide. Even though only a tiny amount (less than 1/10th of one percent) is added to salt, the compound will break up and the iodine will evaporate after a short while. So, chemists found a solution – adding (2) glucose (sugar) to the mixture to stabilize things. So salt has sugar in it? Yes, albeit a small percentage (again, less than 1/10th of one percent).
On top of that, (3) Calcium silicate is also added to table salt to help keep it from caking together. Salt grabs water from the air, and the water dissolves the salt. When the reaction is over, you end up with a lump of salt instead of the free-flowing grains that we like. The calcium silicate works because it absorbs water but does not dissolve.
The book goes on to remind us that…
salt is used for everything from making ice cream to keeping meat colorful.
And did you know that salt was added to shampoo to alter its viscosity (thickness)? I didn’t, and it definitely surprised me. Be sure to check out Why There’s Antifreeze in Your Toothpaste here.
Comments (6)
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alternate title for article – “3 good reasons to use kosher or sea salt”
I didn’t realize just how much flavor the additives took away from table salt – kosher or sea salt makes a big difference, and you don’t have to use much
:)
posted by Clotho on 12-13-2007 at 10:10 am
I work at a cosmetics and personal care manufacturing facility, in charge of product development. The “antifreeze” that everyone keeps talking about is not the same as the kind you put into your car, but it does have a property that lowers the freezing point of water. Salt is used in a ridiculous number of products (toothpaste, shampoo, conditioner, spray deodorant, on and on), but any liquid soap product is (8% likely to list sodium chloride as an ingredient. Fascinating, eh??
posted by adrienne on 12-13-2007 at 11:20 am
^^^^ 98%,that is!
posted by adrienne on 12-13-2007 at 11:21 am
The nuclear power plant my undergrad college was near distributed iodine pills to all us students, with the instructions that we were to take them in the event of a meltdown. Fun times.
Given the choice I think I’d rather have the iodized salt, thanks.
posted by Katherine on 12-13-2007 at 12:35 pm
Aaaand that’s why I use sea salt when I cook. I found out within the first few seconds of using it that it takes a lot less for food to taste WAY better.
And I knew about the salt in the shampoo thing (I like to read ingredient labels in the shower. I’m dorky like that 8D), and theres actually a shampoo that’s made of mostly salt, I haven’t tried it myself, but reviews say it works.
posted by heather on 12-13-2007 at 10:12 pm
Honestly, the salt will kill you first. I hope you like goiters! :D
Did you know that the chemical compound dihydrogen oxide is present in large quantities in almost all foods, including organics? In large enough quantities, it can lower oxygen levels in your blood. It is a main component of many liquid pesticides and household cleaners. It is a major cause of death among XTC abusers. It can be found in most, if not all residential and industrial sewage. In vapor form, it can cause severe burns. It has been known to be used in various forms of torture. Solid dihydrogen oxide was an intregal factor that cause the sinking of the Titanic. It’s often used as a filler in diet beers.
Please, read the MSDS on this dangerous chemical. It claims the lives of countless individuals every day, including children.
posted by Blake on 7-18-2008 at 12:02 pm