Irish Moss and Iodine, an observation

[Silver_Is_Money]

General advice has always been to avoid adding standard 'iodized' table salt to your brewing water in order to avoid iodine, but I just noticed that a seaweed called Irish Moss has factors more iodine than table salt, gram for gram, and many of us (myself included) have been adding Irish Moss by the TSP.

As such, it would appear that the amount of iodine in table salt should be of less concern than for Irish Moss.

 

[ajdelange]

That's certainly an interesting observation. The first thing I would do is boil some irish moss, cool the resultant solution and drop some of it onto a raw potato slice I'd actually add some soluble starch solution but I'm guessing you may not keep that in the kitchen cupboard. But you might keep cornstarch. That should work and you woiuldn't have to sacrifice a potato.

This thought got me wondering as to whether they still teach kids in grammar school about iodine and potato slices or does that take up valuable time needed for LGBNSPQR sensitivity training.

 

[Silver_Is_Money]

The best I can tell after doing some searching on this subject is that:

Iodized table salt has 45 mcg. of iodine per gram (in the USA, this varies by country)

Irish Moss has roughly 300 mcg. of iodine per gram

 

[ajdelange]

Have you tried the potato experiment?

If you want to get more quantititative than that add a little hydrogen peroxide to that (to oxidize all the free I- to I2) and then titrate with photographer's hypo (perhaps not so easy to get as it once was).

 

[BeerChemistWhiskey]

General advice has always been to avoid adding standard 'iodized' table salt to your brewing water in order to avoid iodine, but I just noticed that a seaweed called Irish Moss has factors more iodine than table salt, gram for gram, and many of us (myself included) have been adding Irish Moss by the TSP.

Assuming that the iodine in iodized salt is added through the use of inorganic iodine salts, and that the iodine in Irish Moss is present in the form of organoiodine compounds, I would say there is a possibility that either form could have different effects/levels of effect?

Couldn't find much to help in this quandary in a quick google search.

 

[ajdelange]

It turns out that one of the reasons we have large Irish and Scottish populations in the US and Canada is that the iodine is so tightly bound in sea weeds that they have to be ashed in order to extract it. The discovery of alternate sources of iodine (and soda ash) put thousands employed in the cottage industry that extracted these from seaweed along the Irish and Scottish coasts out of work causing them to emigrate to the new world. There were other causes too (potato famine, clearances...) Thus it appears that just boiling isn't going to release much iodide into the wort. The experiments I suggested earlier would validate this.