Iodine Starch test

I wanted to try the Iodine Starch conversion test. I bought Iodine Tincture 2% U.S.P. (first aid antiseptic) from the local pharmacy.

Never really got it to work. Even prior to sparging, the color stayed the same. Am I using the wrong stuff?

If it stays the same color, you are fine. It turns black/purple in the presence of unconverted starch.

Next time try it on some mash liquid right after you dough in. Then you'll see it turn purple.

I tried the test about 30 mins in to the mash, and the color already had not changed. I was wondering if the 2% U.S.P. was not enough iodine to make the test work.
Looks like some others are just using the cleaning solution iodophor...is that correct?

FenoMeno said:

I tried the test about 30 mins in to the mash, and the color already had not changed. I was wondering if the 2% U.S.P. was not enough iodine to make the test work.
Looks like some others are just using the cleaning solution iodophor...is that correct?

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With the highly converted malt these days, conversion after 30 minutes is pretty common. I would test it at the beginning of the mash.

I wanted to try the Iodine Starch conversion test. I bought Iodine Tincture 2% U.S.P. (first aid antiseptic) from the local pharmacy.
Never really got it to work. Even prior to sparging, the color stayed the same.

Click to expand...

Here is a sample of the most common test.
Put wort and Iodine into one cavity each as a control sample.
Put wort into one more cavity and add a drop of Iodine and watch the reaction and compare to the original color of the Iodine/wort.



A much better method is the chalk or Kaiser method I use.

Looks like some others are just using the cleaning solution iodophor...is that correct?

Click to expand...

Yes

Cheers,
ClaudiusB

FenoMeno said:

I bought Iodine Tincture 2% U.S.P. (first aid antiseptic) from the local pharmacy.
:

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I probably have the exact same little brown bottle w/ tan label that you have (from walgreens) and yes, it will turn purple in the presence of starch.

Mine saved my butt on a largely wheat batch that wouldn't convert after an hour. Took 90 mins.

FenoMeno said:

I wanted to try the Iodine Starch conversion test. I bought Iodine Tincture 2% U.S.P. (first aid antiseptic) from the local pharmacy.

Never really got it to work. Even prior to sparging, the color stayed the same. Am I using the wrong stuff?

Click to expand...

I just saw this now and wonderd if the OP ever go any results? I have also tried and failed but i used the "colorless/clear" iodine ticture and that does not work!! went for the "normal" one (brown'ish/yellow) and it works like a charm!!

Thanks for the input. I did fine with the Walgreens bottle, but found it just as easy and much cheaper to use Iodophor which I already had for sanitation. both worked good-