Author Topic: Conversion time trame  (Read 1862 times)

Offline swlusk

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Conversion time trame
« on: March 28, 2014, 06:12:51 AM »
I typically do half batch all grain using a 3 gallon cooler mash tun.  I'm on my 5th batch using this equipment and I've had good results getting an average of 75% efficiency with my grind. Interestingly enough though, everyone talks of conversion in around an hour. With my set up It typically takes me 1.5 to 2 hours for conversion to occur while maintaining my target temp within a degree for the entire time. I've experienced this at different temp rests, it always takes me closer to 2 hours as confirmed by iodine test. I've been quite anal about carefully checking my conversion since I've been using this mash tun and as a result it seems to have cured my chill haze problem so I think I'm on the right track.

I'm just curious if anyone else routinely mashes this long with their equipment.
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Offline beersk

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Re: Conversion time trame
« Reply #1 on: March 28, 2014, 06:40:16 AM »
That seems weird. I'm no expert on the subject, but that just seems odd. I mash for 60 minutes typically and average between 75 and 80% efficiency and the beer clears after being in the keg for a couple weeks.
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Offline HoosierBrew

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Re: Conversion time trame
« Reply #2 on: March 28, 2014, 06:46:15 AM »
I quit doing the iodine test a long time ago - it is really inconsistent and unreliable IMO.  If you mash in a cooler at normal temps (ie., 150 -156 F), you're getting conversion according to many in under an hour. I will mash for ~ 90 minutes when I mash sub 150F, but you don't need 2 hours at a standard mash temp.
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Offline kramerog

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Re: Conversion time trame
« Reply #3 on: March 28, 2014, 06:53:29 AM »
Somethings to consider.  Coarseness of grind - the coarser the grind the longer it takes for the enzymes to get to the last starch molecules.  Temperature:  are you sure your thermometer is reliable?  If your thermometer reads 10 F high then that would largely explain why your mash takes so long.  Chemistry factors which are probably secondary to coarseness and temperature:  mash pH and calcium.  Calcium is necessary for beta-amylase, but beta-amylase doesn't play a big role in breaking down starch unlike alpha-amylase. 

I'm usually at 90% efficiency with a 60-minute mash and no mash-out. 
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Offline riverrat

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Re: Conversion time trame
« Reply #4 on: March 28, 2014, 06:55:24 AM »
How confident are you in the accuracy of your thermometer?  A few degrees can be a big difference.

You can check your thermometer in boiling water (the purer the better).  It should read 212 F during a solid rolling boil (less at elevation, there are online charts for this).  It's not quite the same range as mash temps, but it should let you know if you are significantly off.
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Offline majorvices

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Re: Conversion time trame
« Reply #5 on: March 28, 2014, 07:07:28 AM »
I skipped doing iodine tests years ago. Too many false reading and stressing about nothing. And in the presence of grain husk it will always turn black/purple.
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Offline ynotbrusum

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Re: Conversion time trame
« Reply #6 on: March 28, 2014, 07:12:55 AM »
I can assure the OP that something is amiss if the conversion takes that long - I use a Themapen after frustration with slow read thermometers and found that a really good stir of a couple minutes or more, if necessary, gets uniformity of the mash temperature throughout, elimination of even the smallest doughballs, and a slightly better efficiency than I previously experienced after first switching to all grain. 

Also, calibration at boiling is not a guarantee - The temperature at a boil could read right and at a mash temp could be way off, but try the calibration at boil and at ice water temps and hope for the best.

Lastly, grain crush can make a huge difference - many LHBS mill gaps are set pretty large compared to those used by guys that get great efficiencies.  I use a JSP Malt Mill and love the factory setting for the sweet spot in my setup, but my efficiency is right about 75% and I am happy with that.

I hope that helps!  Don't be discouraged, you can get conversion in less than an hour, if you dial in the factors mentioned here and by others above.
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Offline hopfenundmalz

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Re: Conversion time trame
« Reply #7 on: March 28, 2014, 07:24:31 AM »
I Agee with all that has been said above. Crush, temp, mash pH are very important.

My question is what grains are you using? A mash of dark Munich was a little problematic for me once, I have concluded that sack of grain was a little week for Diastatic Power, as the next bag of dark Munich had no problems.
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Offline a10t2

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Re: Conversion time trame
« Reply #8 on: March 28, 2014, 08:03:45 AM »
Almost certainly the problem is a false positive with the iodine test. Post the protocol you're using; it's surprisingly tricky to do right. Monitoring gravity is much more reliable, IME.
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Offline swlusk

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Re: Conversion time trame
« Reply #9 on: March 28, 2014, 08:14:51 AM »
Typically I dip as clean a sample as I can with a spoon off the top onto a white plate and drip iodine on the side and watch the junction between the two for any black.

Today after batch sparging my first runnings I retested and it showed complete conversion where as my last test of the wort from the top of the cooler tun still showed a slight reaction.

My recipe today was:
2 lbs 15.7 oz Pale Ale Malt 2-Row (Briess) (3.5 SRM) Grain 1 55.1 %
1 lbs 6.1 oz Munich 10L (Briess) (10.0 SRM) Grain 2 25.6 %
9.5 oz Caramel Malt - 40L (Briess) (40.0 SRM) Grain 3 11.0 %
4.8 oz Caramel Malt - 60L (Briess) (60.0 SRM) Grain 4 5.5 %
2.4 oz Extra Special (Briess) (130.0 SRM)

I crush pretty course with a few kernels only split in half with a good number of large hull.

I use a traceable lollipop thermometer but I double check with a big daddy dial.
Doughed in today to 149.5 with a target of 150. It held 145.9 for an hour and dropped to 148.5 by hour 2.
Batch sparged and collected 4.15 gallons (doing a 2.5 gallon half batch 90 minute boil)
and my preboil gravity was 1.035 @ about 75% efficiency all according to Beersmith.

I think your right, flawed iodine test. I need a new test ;)
« Last Edit: March 28, 2014, 08:17:34 AM by swlusk »
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Offline hopfenundmalz

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Re: Conversion time trame
« Reply #10 on: March 28, 2014, 09:14:25 AM »
Briess 2 row is "hot" as far as DP goes, so it should convert with no problems.

I have been measuring conversion efficiency for the last year. It is explained on Kai's page. If you are in the hi 90s you are good to go.
http://www.braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Conversion_efficiency


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Offline mainebrewer

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Re: Conversion time trame
« Reply #11 on: March 29, 2014, 03:55:14 AM »
+1 to the Braukaiser reference! Easy quick check for conversion.
Awful lot of other good stuff on that site as well.
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Online dmtaylor

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Re: Conversion time trame
« Reply #12 on: March 29, 2014, 04:42:17 AM »
I've never done an iodine test.  I've brewed about 40 batches with mash times of just 40 minutes.  Average batch size = 2.5 gallons.  Crush = very hard, lots of flour.  Average mash temperature = 149 F.  Average efficiency = upper 80s.  Average attenuation = 75% (depends on yeast strain used, etc.).  I never do a mashout.

Believe it or not, you've got a ton of sugars produced in just the first 10 minutes of the mash.  The problem is you've still got a lot of convertible starches left at that point as well.  With a proper crush, after 30 minutes, most of the starches have been converted, but the sugars produced are relatively unfermentable ones.  The extra time to 40-45 minutes is needed to change those unfermentable sugars to fermentable ones.  If I would mash for a full 60-90 minutes, would my efficiency improve?  Yeah, by like 1-2 gravity points -- big whoop.  Would fermentability improve?  Yeah, by like 1-2 gravity points.  I suck this up and quit the mash at 40 minutes, and have been very happy for many years.  And hey, I saved 20+ minutes of my life on every batch.  Try it and see for yourself.

You don't need no stinking iodine for the beer to turn out great.  However it certainly would help if you crush hard.  Crush till you're scared.  If you do, your efficiency will shoot up by about 10 points overnight.
« Last Edit: March 29, 2014, 05:08:31 AM by dmtaylor »
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Offline majorvices

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Re: Conversion time trame
« Reply #13 on: March 29, 2014, 06:12:38 AM »
With today's malts, all you need to concentrate on is getting the pH right - 5.4-5.6 (I try to target 5.4). No need for iodine test. 45-60 minute rest for 150-156 and 90 minute rest for 146-148 (I don't mash lower than that) and with a proper crush you should easily get 75% efficiency or better.
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Offline swlusk

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Re: Conversion time trame
« Reply #14 on: March 29, 2014, 06:49:59 AM »
Briess 2 row is "hot" as far as DP goes, so it should convert with no problems.

I have been measuring conversion efficiency for the last year. It is explained on Kai's page. If you are in the hi 90s you are good to go.
http://www.braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Conversion_efficiency
Great stuff here, thanks.

Thanks to all for the help! Just another step in the process of taming this beast! ;)
Corripe Cervisiam

If I ever go missing I want my picture on a beer instead of a milk carton , I want fun people to find me