Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > Is the iodine test the only way to test starch conversion?
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Old 02-12-2011, 11:39 AM   #1
worldzfree
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Default Is the iodine test the only way to test starch conversion?

After having a couple of AG sessions under my belt I am starting to add some more testing. Is the iodine test the only way to determine that conversion is complete or can a PH meter or refractometer be used?


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Old 02-12-2011, 12:57 PM   #2
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Neither a pH meter nor a refractometer will indicate your degree of conversion reliably.


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Old 02-12-2011, 03:10 PM   #3
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I don't know of another method readily available to a homebrewer. Oh yeah, welcome to the forum, its nice to see another local.
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Old 02-12-2011, 03:16 PM   #4
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Quote:
Originally Posted by worldzfree View Post
After having a couple of AG sessions under my belt I am starting to add some more testing. Is the iodine test the only way to determine that conversion is complete or can a PH meter or refractometer be used?
Honestly an iodine test is one of those steps you can eliminate without much worry. Adding well-crushed modern brewing malt to hot water, let it be for 60 minutes and it's going to convert without a problem. You are much more likely to get a false negative iodine test reading than run into starch conversion problems.
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Old 02-12-2011, 03:25 PM   #5
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If you trust those calculators that predict first running SG, then why not test for conversion with a refractometer? If the predicted sugar is in solution, why not assume conversion is done. Or at least, done enough ;-)
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Old 02-12-2011, 09:03 PM   #6
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Quote:
Originally Posted by BigEd View Post
Honestly an iodine test is one of those steps you can eliminate without much worry. Adding well-crushed modern brewing malt to hot water, let it be for 60 minutes and it's going to convert without a problem. You are much more likely to get a false negative iodine test reading than run into starch conversion problems.

Unless you're using adjuncts. And even then, do a 90 minute mash and you should be GTG.
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Old 02-12-2011, 09:18 PM   #7
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http://braukaiser.com/wiki/index.php...ion_efficiency


Measure the first wort gravity. If you've converted properly you will have the same gravity as is the chart.


On normal beers (5-7% alcohol) I only do 45 minute mashes and have never had a problem


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