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-   -   Pharmacy iodine for testing for starch (http://www.homebrewtalk.com/f39/pharmacy-iodine-testing-starch-317631/)

Moonraker 03-31-2012 09:23 PM

Pharmacy iodine for testing for starch
 
Planning my first mash tomorrow and I went to the pharmacy to get some iodine so that I could test for remaining starches after conversion. There were two alternatives - tincture of iodine (2% iodine)? and 'decolorized' iodine. Are either of these good?

JLem 03-31-2012 09:29 PM

I use the tincture and it works great. I bet either would work. Though I've never heard of decolored iodine

RM-MN 03-31-2012 09:32 PM

You'll want tincture of iodine. It needs to be brownish and should stay that way when you test. If it turns black or purple there is still starch to be converted.

ChuckO 03-31-2012 09:40 PM

You can also use Iodophore or Betadine, as they produce the same result.

JLem 03-31-2012 09:45 PM

Quote:

Originally Posted by RM-MN
You'll want tincture of iodine. It needs to be brownish and should stay that way when you test. If it turns black or purple there is still starch to be converted.

As long as the decolored stuff turns black in the presence of starch it would be fine. Just not sure if it does turn black or if that reaction is also decolored. Best bet is to use the tincture to be safe.

helibrewer 03-31-2012 09:49 PM

With the highly modified grains these days you don't really need to do the iodine test. Most of the conversion happens in the first 20 minutes, the rest of the mash is "making tea", extracting colors and flavor.

Moonraker 03-31-2012 09:54 PM

Awesome, thanks guys. I'll grab some tincture.


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