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Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > BIAB Brewing > Tell me about mash time.
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Old 11-20-2013, 04:42 PM   #1
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Default Tell me about mash time.

i decided to make a Roggenbier with some of the unmalted rye I have in my bin. Since I was using a bit of unmalted rye, I wondered how well this batch would convert so I planned on an iodine test for conversion.

Batch size 2.5 gallons BIAB
Grains milled fine in my Corona style mill like I always do.

2 Lbs unmalted rye
1 LB malted rye (Briess)
1.5 Lbs 2 row malted barley (Rahr)
4 Oz C-60 Caramel malt (Briess)
1.5 Oz Chocolate malt (Briess) 350 L

.5 Oz Cascade at 60
.5 Oz Cascade at 10

English ale yeast (White labs liquid)

I had 3 drops of iodine on a white plate to do my test for starch. At dough in it turned blue/purple/black which showed the presence of starch. My previous experiment had tested negative for starch at 7 minutes so this was to see just how quickly the enzymes work. My second sample was to be at 3 minutes and then next would then be at 6 minutes. Uh, what happened? At 3 minutes the iodine wouldn't change color at all when I added wort. I didn't even try it at 6 minutes.

Tell me again about the 60 to 90 minute mash times needed. I did let this one continue for 25 but I wonder if even that was more than needed.

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Old 11-24-2013, 08:26 PM   #2
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Its possible that with a very fine grind, like it sounds like you're doing, that you'll get conversion faster than a regular milled grain would. Part of the 60 min mash involves extraction of the starch from the grain fragments, but if its flour that will necessarily occur much faster. That being said, if you're trying to figure out the minimal amount of time for your mash with your grind, I wouldn't just use an iodine test as an indication that you can stop mashing. Iodine is great as a quick test, but a negative reaction doesn't mean that all the starch is converted, just a good deal of it. You also need to give the amylases enough time to properly process the starch fragments. While the starch may be broken down enough to test negative with iodine, its possible that its not been fully converted to maltose/maltotriose/etc. The only good way I can think to test that would be to see what your fermentability is at short mash times and see if it matches up with your mash temp, and to check to see if any haze develops from larger starch fragments.

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Old 11-25-2013, 05:33 PM   #3
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Could you simply check the gravity of the mash and see if you hit your expected gravity? If so, then you are done?

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