Conversion not happening!

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Khirsah17

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Hello all,

Man, I am really starting to get nervous. I made my mash at 9:30 this morning and by 2:30 this afternoon, iodine tests still turning very black, very quickly.

Some beer background: I am trying to really test the limits of my system and AG brewing skills. I have a 10 gallon mash tun and am trying to make a 17.5% big beer. I have 36 pounds of grain in the tun with a water ratio of about 0.8 gallons per pound of grain. The initial temperature was about 146 (I lost alot of heat because of the stirring I had to do to make sure there werent dry pockets of grain). I have done two decoctions and successfully brought it up to 150, which is my target temp. But still, its been almost 5 hours and i still havent reached conversion.

What gives? I can't check my ph unfortunately, so no info there. Has anyone had a beer take this long?
 
That is a pretty dry mash, that could be your first problem. i would never go less than 1 qt. per pound of grain, and even that is pushing the envelope.
 
Are you getting husks in your sample when you add the iodine? If there is husk it will probably turn black even if you have had conversion.
 
Hmmm, thats an interesting thought. I guess I've tried to be pretty careful about just drawing liquid only. However, just changed my grain mill gap to .039 from .042", and I would say my grain husks were smaller in general. Maybe I just have bits of husk that I can't see in the wort.

I just tried to do a iodine test, being supremely careful about getting liquid only, and it still turned black :(

Im starting to get a tad bit worried!
 
Raise the temperature! that's a LOT of grain, and if it's not converting in 5 hours you probably are below your target temperature still.

Calibrate your thermometer, shoot for 154, stir, add a couple gallons of 170 degree water, stir.

And above all, comply with rule #1, DON'T WORRY.
 
Maybe stir well, and pull a hydrometer samples worth of wort. Test the SG...you should be somewhere north of your desired pre-boil gravity (maybe 25-30% for first runnings). If you're near that, declare victory and start sparging.
 
Put it all in the pot and add heat and stir. don't go over 155, check for starch conversion every 5 minutes, when you start to just see a little black, throw everything back in the mash tun and proceed normally.

Good luck, now that I'm giving "expert" advice, I'm sure Murphey will be visiting me in a couple hours when I start my brewday.
 
I don't see how the hydrometer could tell me whether or not my starches are converted...unless starches don't disolve at all. Any thoughts?
 
The wort does taste sweet, but there is no more room for anything! I have been doing mini decoctions (3) of one gallon of grist to raise my temperatures back up to 150 F.
 
Oh, and how did i fit 36 lb of grain in a ten gallon mash tun? According to Palmer:

mash volume = weight of grain (lb) * (water to grain ratio + 0.32)

so, 36 lb of grain and water to grain ratio of 0.75, is 38.5 qts. 10 gallon mash tun is 40 quarts. So i started with ratio 0.75, but continued to add water as I had room, so i ended up with a little bit more. Worked out just fine, but I was expecting the problems to start with the sparge, not in the mash.
 
Khirsah17 said:
Oh, and how did i fit 36 lb of grain in a ten gallon mash tun? According to Palmer:

mash volume = weight of grain (lb) * (water to grain ratio + 0.32)

so, 36 lb of grain and water to grain ratio of 0.75, is 38.5 qts. 10 gallon mash tun is 40 quarts. So i started with ratio 0.75, but continued to add water as I had room, so i ended up with a little bit more. Worked out just fine, but I was expecting the problems to start with the sparge, not in the mash.

Yeah math works out, I just never imagined trying for more than 25lbs in my ten gallon tun. I'm impressed you went for it.
 
Most of the starches will not dissolve until you hit 149F. You also have a very, very stiff mash, which means slow dissolving. I would never go under 1.1 qt/pound.
 
With such a stiff mash your enzymes are slowed down by product inhibition. There is a reason why the ratio of your grain to water is supposed to be about 1-1.25. Also you may be seeing black because there is still so much debris etc in your concentrated mash. It can be hard to distinguish if the "fluid" portion is turning black or only tiny particulate matter in solution.
 
Well, thanks for all the responses. Turns out that husk material was giving me false readings. I was taking measurements based on the wort from the top of the mas tun. I finally just said screw it and lets move on with the sparge. Once the runnings went clear, I ran another iodine test and it passed with flying colors.. conversion! I just wish I would have thought of trying that before I wasted so much time in my day.

As a side note, I got an OG of about 1.162 (corrected). Awesome! The only problem I think is that my grains got real caramelized because i had to boil forever to get this down to a 5 gallon batch. Now comes the challenge of yeast attenuation. Pretty exciting. So far, its been tough, but i highly recommend everyone trying to brew a obscenely big batch of beer!
 
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