starch conversion times???

What went wrong? Was this supposed to happen? Should I throw it out? What do I do now?

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starch conversion times???

Postby john_galt » Tue Sep 03, 2002 6:26 am

i did two 5 gallon batches of the same beer over the weekend.....i made the recipes my self.....i am curious about what other people are getting for the actual times for complete starch conversions; i am using iodine for testing....the batch was 11.5 pounds of grain in about 4.5 gallons of water....both batches took about 6.5 hours @150-152 degrees for complete conversion.....if this is average time, then why do most books say that it only takes 30 minutes to 90 minutes????.....SOMEBODY HELP PLEASE
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too long

Postby Gravity Thrills » Tue Sep 03, 2002 10:16 am

Conversion shouldn't take that long. My first suspicion is your mash pH is too high, which will have your enzymes working out of optimal range. If you have a lot of dark malt in your grain bill, this is probably not the case, but if your grist is exclusively light grains check pH and add gypsum or phosphoric acid as needed. Then also acidify your mashout and sparge water with phosphoric acid so you are near the pH optimum of 5.2-5.4.

a 90 minute mash should convert 90-95% of your starch, I would estimate.

Cheers
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Who is John Galt?

Postby Monkey Man » Tue Sep 03, 2002 11:15 am

Who is John Galt?
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Hey John

Postby Liquid Blur » Tue Sep 03, 2002 12:31 pm

You're not in the military are you? I went to tech school with a John Galt. At least I think his first name was John.
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Thermo

Postby Freon12 » Tue Sep 03, 2002 12:53 pm

Tempreture instrument could be off or out of calibration? Just a shot.

-
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Way too much water

Postby Azorean Brewer » Tue Sep 03, 2002 4:21 pm

John, I had a problem when I started out too ... it took me 2 1/2 hours the first time out, then I found out I was using too much water and it was to high in PH. A good rule of thumb is 1 - 1 1/3 quarts of water per pound of grain. When I brew an 11-12 pound batch I use no more than 3 gallons of water (just over 1 quart per pound in the mash). At 1 1/3 quarts per pound for 11 pounds would be 3.6 gallons maximum, your 4.5 gallons I suspect is way too much. Stick to the low end, that way if you have to add water to raise the temp you have room to spare, plus you'll improve your mash effiency. I also use 1 teaspoon of Gypsum and one half teaspoon of Citric acid in my mash tun, I'll look for phosphoric acid next time I shop. Good luck on this issue. P.S. I use the iodine test also and I am fully mashed out at 90 minutes now.

Paul.
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only a little too much...

Postby Gravity Thrills » Tue Sep 03, 2002 6:19 pm

Az is right - you have a bit too much water in the mash tun. But, if you're shooting for a 1.33 quart/lb ratio instead of 1 qt/lb (both will work fine), you are only high by about a half-gallon. The enzyme kinetics is uphill with too much water, but I wouldn't think it would be so bad that conversion takes 5-6 hrs.

Someone in the thread mentioned checking the accuracy/calibration on your thermometer. You might also examine your mash-in protocol and note if the grist spends much time (more than 5 minutes) above 156-158F or above before you get it stirred up and in your target range. Most authors suggest adding water to grain but I do it the other way around because I'm less likely to overshoot my target mash-in temp that way. Much of your enzyme activity will be inactivated after several minutes above 160F or so.

Cheers.
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Check all posts John

Postby Azorean Brewer » Wed Sep 04, 2002 2:40 am

John in case you get email notification there are sub-posts here.

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Not intending to be a peeing contest ...

Postby Azorean Brewer » Wed Sep 04, 2002 2:45 am

Sorry Gravity, I am not intending to russle anybodies feather, and definitly don't mean to offend anyone ... only want John to understand how to do the calculations himself.

John,
Lower Spec = 11.5 X 1.00 = 11.5 Quarts
Upper Spec = 11.5 X 1.33 = 15.3 Quarts

John used 18 quarts of water ... or 2.667 quarts too much (from the upper spec,) as Graity stated and 6.5 (1.6 gallons too much) on the low spec.

Y'all get the picture, just trying to understand all of the facts. However I agree with everyone that John should get his Thermometer checked / calibrated / spend the extra $5.00 and buy a new one ... good to have two anyway, what you don't want to happen is drop it (like I did) just as you were going to used it and have no backup ... That really sucks.

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de nada

Postby Gravity Thrills » Wed Sep 04, 2002 8:10 am

No feathers have been rustled... but if anyone can appreciate a peeing contest, it's homebrew mass-consumers :-) Maybe an exhibition sport in the next Olympics?

Cheers,
Jim
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iodine test

Postby andytv » Wed Sep 04, 2002 8:33 am

I've always had some issues with the iodine test, it seems that even when I am sure that I have converted effectively(my gravities almost always are dead nuts on & beer turns out good)there is a color change. I've heard/read that slight color change is expected during an iodine test; I've heard that an immediate turn to black indicates unconverted starches, but a turn to brown is OK. I'd be interested in John_galt's test procedure, as well as all of the other members of this forum.

Andy
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ditched iodine test

Postby Gravity Thrills » Wed Sep 04, 2002 9:40 am

I agree that the iodine test is most often a waste of time, and rarely do one any more. Better to spend the time on a pH test. If your pH and temperature are within bounds, you'll get conversion.

if you severely overshot mash-in temp and are worried you have killed your enzyme activity, an iodine test after 60-90 minutes is probably a good way to check.

Cheers,
Jim
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Yes....the "Arc"

Postby BillyBock » Wed Sep 04, 2002 8:22 pm

I think you're on to something, Gravity. The "Arc" could follow the javelin toss. IMHO homebrew mass-consumers have more robust bladders that the Lite Beer crowd--after all, lite beer is for people that just like to pee a lot :-)
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thanks

Postby john_galt » Fri Sep 06, 2002 6:31 am

i thought that might be it....i got a new thermometer....doesn't seem to be the problem....pobably the pH
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nope

Postby john_galt » Fri Sep 06, 2002 6:32 am

nope not me......ever read "ATLAS SHRUGGED" by Ayn Rand?
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