Starch conversion problems - Home Brew Forums

Register Now!
Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > Starch conversion problems

Reply
 
Thread Tools
Old 07-06-2008, 04:41 PM   #1
Donasay
Recipes 
 
Oct 2007
Boston
Posts: 1,567
Liked 8 Times on 8 Posts



I have some problems with my starch conversions and think there might be two possible problems. I mashed in about an hour and a half ago and keep doing iodine tests, but conversion isn't complete. I mashed in and hit my temperatures almost exactly, so mash temp isn't the problem.

I have narrowed it down to two variables, first possiblity is that my grain got cooked in the back seat of my car and second is that I have bad iodine. I purchased the grain at my lhbs on friday after work and let it sit in the back seat of my car till this morning essentially letting it bake in the 120 degree heat inside the car all day yesterday. The other is that I have bad iodine, which I left sitting out in the sun for a day and a half last time I brewed.

I don't know what to do in this situation, but if it doesn't convert in the next 30 minutes I am going to mash out anyway and just brew as normal. Is it possible that the heat inside my car denatured the enzymes in this grain, or am I just being paranoid.
__________________
No matter how rich you are, you can still only drink 16 or 17 liters of beer a day.

Quote:
Originally Posted by quixotic View Post
The true definition of an addiction: not stopping even when a dog is having his way with you.:D
http://www.solutionsinmetal.com/

 
Reply With Quote
Old 07-06-2008, 04:46 PM   #2
FlyGuy
 
FlyGuy's Avatar
Recipes 
 
Jan 2007
Calgary, Alberta
Posts: 3,605
Liked 178 Times on 51 Posts


Do you normally get a positive indication of full conversion when using iodine? Is it that this one brew is behaving differently? If so, tough call.

I stopped doing an iodine conversion test because I found it terribly unreliable (lots of false negatives).

Try recirculating until you get clear wort, then take an iodine test. Sometimes husk material or other suspended junk will really throw off the test.

 
Reply With Quote
Old 07-06-2008, 04:54 PM   #3
Donasay
Recipes 
 
Oct 2007
Boston
Posts: 1,567
Liked 8 Times on 8 Posts


I do normally get indication, but I have no way of knowing false positive or false negative, I have gotten positive starch conversion after 30 minutes on previous batches, and sometimes it takes 2 hours.
__________________
No matter how rich you are, you can still only drink 16 or 17 liters of beer a day.

Quote:
Originally Posted by quixotic View Post
The true definition of an addiction: not stopping even when a dog is having his way with you.:D
http://www.solutionsinmetal.com/

 
Reply With Quote
Old 07-06-2008, 04:57 PM   #4
Joe Camel
Recipes 
 
Mar 2008
Charlottetown, PE, Canada
Posts: 284
Liked 3 Times on 3 Posts


120 degree dry heat while the grain is dried is not the culprit, the malt is kiln dried at temperatures hotter than this for longer times before it's sold to you.

I agree with Fly that it's not likely the iodine but how you're using it, probably getting a bit of husk in the sample. Use the chalk method, place the drop of wort from your thermometer on a piece of sidewalk chalk and then apply the iodine to it, this lessens the risk of grain bits. once done, shave that piece of chalk off with a chisel or carpet knife to expose a clean piece for the next sample.

 
Reply With Quote
Old 07-06-2008, 05:00 PM   #5
FlyGuy
 
FlyGuy's Avatar
Recipes 
 
Jan 2007
Calgary, Alberta
Posts: 3,605
Liked 178 Times on 51 Posts


Quote:
Originally Posted by Donasay View Post
I do normally get indication, but I have no way of knowing false positive or false negative, I have gotten positive starch conversion after 30 minutes on previous batches, and sometimes it takes 2 hours.
Well, it is possible that you cooked your grains in the car, although even 120 F shouldn't be enough to denature all your diastatic enzymes. I would suggest that if the starch test only shows a bit of reaction to the iodine, you are done. You might try a recirc to see if that changes anything.

 
Reply With Quote
Old 07-06-2008, 07:52 PM   #6
RichBrewer
HBT_LIFETIMESUPPORTER.png
 
RichBrewer's Avatar
Recipes 
 
Feb 2006
Denver, Colorado
Posts: 5,892
Liked 168 Times on 88 Posts


When I first started brewing AG, I did an iodine test for conversion and I ended up doing two our mashes. I then learned that I probably had conversion but the test was unreliable. I don't bother with iodine tests any longer. I mash for an hour and then sparge. I get decent efficiency and normal attenuation most of the time.
They say that modern malts actually convert in as little as 30 minutes.

One question: What is your grain bill? Depending on what you are using, the conversion time could vary.
__________________
Cheers,
Rich

 
Reply With Quote
Old 07-06-2008, 08:57 PM   #7
Donasay
Recipes 
 
Oct 2007
Boston
Posts: 1,567
Liked 8 Times on 8 Posts


Well I just brewed with it and the gravity came out fine, it was 15lbs of marris otter and 1 lb of crystal 60. I was just really worried that I had cooked the grain by leaving it in the back seat of my car for a couple days. Additionally the iodine tests are always more accurate when the idoine is fresh.
__________________
No matter how rich you are, you can still only drink 16 or 17 liters of beer a day.

Quote:
Originally Posted by quixotic View Post
The true definition of an addiction: not stopping even when a dog is having his way with you.:D
http://www.solutionsinmetal.com/

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
starch conversion nickster51 All Grain & Partial Mash Brewing 5 08-28-2009 08:01 PM
Starch to Sugar conversion Cape Brewing Brew Science 19 03-12-2009 05:19 PM
Starch conversion to sugar Orfy Beginners Beer Brewing Forum 2 01-31-2009 01:40 PM
Starch Conversion Test voodoochild7 General Techniques 3 02-28-2007 04:16 AM
Starch Conversion Dark_Ale All Grain & Partial Mash Brewing 5 06-15-2005 01:41 PM


Forum Jump