Mash procedure and iodine test

[luizffgarcia]

Guys, i need some advice related to my mash procedure please.

I just brewed this recipe yesterday and for the first time i tried the iodine test, but i was unable to get the results i was looking for.

I mashed at 65ºc for 60 minutes, and then 77ºc for 30 minutes and the sample was still turning black! Then i extended the 77º for another 20 minutes, tested again and same results!

My question is, should i care about this test at all? How is it possible for this grain bill to not convert even after 2 hours?

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Racer 5 clone
(Bear Republic Brewing Co.)
(5 gallons/19 L, all-grain)
OG = 1.071 FG = 1.015
IBU = 60 SRM = 10 ABV = 7.2%

Ingredients
11.25 lbs. (5.1 kg) 2-row pale malt
1.66 lbs. (0.75 kg) wheat malt
0.625 lbs. (0.28 kg) crystal malt (15 °L)
0.42 lbs. (0.19 kg) dextrose (corn sugar)
0.21 lbs. (95 g) CaraPils malt
6.1 AAU Chinook hops (90 mins)
(0.51 oz./14 g of 12% alpha acids)
8.7 AAU Cascade hops (60 mins)
(1.74 oz./49 g of 5.0% alpha acids)
0.3 oz. Centennial hops (dry hop)
0.3 oz. Amarillo hops (dry hop)
0.2 oz. Cascade hops (dry hop)
0.2 oz. Tomahawk hops (dry hop)
Wyeast 1272 (American Ale II) or White Labs WLP051
(California V) yeast
0.75 cups corn sugar (for priming)

Step by Step
Mash in at 145 °F (63 °C) then ramp temperature to 152 °F (67 °C) for conversion. Mash out to 170 °F (77 °C). Boil for 90 minutes, adding hops at the times indicated in the ingredient list. Ferment at 68 °F (20 °C).
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[billl]

Did you make sure there were no grain pieces in your sample? That gives a false positive.

 

[luizffgarcia]

Did you make sure there were no grain pieces in your sample? That gives a false positive.

I did to the best of my ability...

 

[ncsuwerewolf]

How did your OG turn out? I dont know anyone in my group that tests conversion since modern, reputable malts are so well converted.

 

[luizffgarcia]

How did your OG turn out? I dont know anyone in my group that tests conversion since modern, reputable malts are so well converted.

Well TG was 1071 and OG was 1070, i never have any problems nailing the OG and i even have a 90% efficiency for my setup.

 

[billl]

Can you describe how you tested. eg x amount of wort, y temp, z drops iodine etc. Did you swirl it? What did it actually look like?

Realistically, if you have successfully made beer a bunch of times, the likelihood is that there is something wrong with your "test", not the conversion.

 

[blackford4x4]

What type of iodine are you using?

 

[luizffgarcia]

I took a tablespoon of wort, let it cool in a white plate for a while and used one drop of iodine tincture 2.5%. I didn't swirl it, it looked pitch black.

I am pretty sure there was something wrong with the test and not the mash... Just need to figure out what was wrong and if it is worth performing this test at all

 

[blackford4x4]

It should turn black if starch is present.

 

[RM-MN]

I suspect the wheat malt is the culprit. Unless you adjusted the mill to accommodate the smaller, harder wheat kernels they weren't crushed enough and you didn't get the conversion from them. Since they were such a small percentage of the grain bill that didn't affect your OG very much. Try a small amount of the pale malt with the iodine test. Then try a small amount of the wheat malt the same way.

 

[mongoose33]

How did your OG turn out? I dont know anyone in my group that tests conversion since modern, reputable malts are so well converted.

Well TG was 1071 and OG was 1070, i never have any problems nailing the OG and i even have a 90% efficiency for my setup.

I'm failing to see the problem here. You have a high-sugar wort. Why would you, after a long time of not being concerned with the iodine test, suddenly decide you needed to do that?

You're worried about getting conversion? I'd say 1.070 says you've gotten it.

 

[luizffgarcia]

I'm failing to see the problem here. You have a high-sugar wort. Why would you, after a long time of not being concerned with the iodine test, suddenly decide you needed to do that?

You're worried about getting conversion? I'd say 1.070 says you've gotten it.

That is exactly what is confusing me! LOL

I never performed this test, and after a friend told me i was doing my mash wrong because of not testing the iodine i gave it a try.

I think this test is useless...

 

[billl]

Personally, i think it's hard to tell a dark brown drop of iodine from a black drop of iodine. If you give it a gentle swirl, it will be much more obvious. The fully converted sample will just dilute the dark brown. If starch is present, it balloons out all black.

But yeah, generally not a test you need to run every time. It can be helpful for trouble shooting some issues, but I wouldn't bother with it if you are already making good beer.