BiaB, fine crush, 8 hour mash, 49% efficiency ?! - Home Brew Forums
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Old 08-26-2011, 03:27 PM   #1
manicmethod
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Jul 2010
MD
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So I've been getting bad efficiency. I already had one thread where the consensus was my LHBS crusher.

I got a corona and crushed 20 pounds of grain with a drill attached. Knowing that fast crushing causes problems I ziptied the trigger and let it go at a slow pace (maybe 100 rpm or so). It took about 15 minutes. The grains were well crushed, lots of flour and definitely no uncrushed grains.

I did a fullish volume BiaB, 11 gallons for the 20 pounds. My intention was a 10 gallon batch but the water went up to the top of the basket and I didn't want grains getting out of the basket. I didn't have much room to stir to make sure there were no dry pockets or anything but I poked through the grains with the spoon a few times and everything seemed fine.

The water outside the basket was 150F at this point. I covered the whole thing with a blanket (it was 80F outside) and went to work.

8 hours later it was 120F, I heated to 180 to mashout, pulled out the grains and needed to add some water to do a full boil so I had 2 more gallons at 190F that I poured through the grains (not a real sparge, I know, but I don't normally sparge at all).

As it turns out I needed more water than that, I ended the 60 minute boil with 8 gallons so when I topped it off my gravity (well stirred wort+water) was 1.040 in both fermenters. The target was 1.056.

*sigh*



 
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Old 08-26-2011, 04:11 PM   #2
Haputanlas
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Jan 2010
Austin, TX
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I used to get low efficiencies in BIAB for the following reasons:

1. I wasn't stirring properly
2. Water to Grist ratio was too low (Not your problem obviously)
3. Wasn't sparging

That being said, I didn't realize I wasn't stirring well enough until I used a paint mixer attached to my drill. The efficiency began shooting through the roof.

This is a pic of what I'm talking about:


As long as you stir under the surface and don't let it splash, you shouldn't have to worry about HSA.

I always thought I was stirring properly, but this helped me realize the difference.


Also, until I used a second pot for sparging, my efficiencies wouldn't go higher than 50-60%. After I used a second pot for the sparge, I haven't been below 75-80%.


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Old 08-26-2011, 04:32 PM   #3
gstrawn
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Jun 2011
Athens, Ga
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I use a second pot but another sparge option I've used is heating the mash out and just allowing the grains to drain then redunking 4 times and draining. I would get 70% efficiency usually which I was happy with

 
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Old 08-26-2011, 05:08 PM   #4
manicmethod
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Jul 2010
MD
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Yea, I've seen other people use this sparging method, I just don't have a pot big enough for my basket (it won't even fit in my old 10 gallon kettle.

 
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Old 08-26-2011, 05:12 PM   #5
manicmethod
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Jul 2010
MD
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Quote:
Originally Posted by Haputanlas View Post
I used to get low efficiencies in BIAB for the following reasons:

1. I wasn't stirring properly
2. Water to Grist ratio was too low (Not your problem obviously)
3. Wasn't sparging

That being said, I didn't realize I wasn't stirring well enough until I used a paint mixer attached to my drill. The efficiency began shooting through the roof.
I've seen on here saying you shouldn't mix the mash because of astringency and watery effect, or maybe this is something BiaB'ers have to do?

 
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Old 08-26-2011, 05:19 PM   #6
hopsalot
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Sep 2007
Corpus, Texas
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im thinking that your long mash may have absorbed more sugar rich wort than a typical 1 hour mash, then you has to top off that loss leading to a lower gravity, so unless you are souring a mash, I would not leave it in a mash tun for an extended period of time.

 
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Old 08-26-2011, 05:24 PM   #7
TopherM
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Mar 2011
St. Petersburg, FL
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Two suggestions:

1) Next time do a double mill. A fine crush is all good, but you are still going to miss a good % of the grains altogether. Mill, dump the milled grains back in, and mill again.

2) Did you do a really good drain of the bag? I know it would be extremely difficult to squeeze a 20lb grain bag, but you have to get the wort out of there somehow. In a 20lb grian bill, there is almost 1.5 GALLONS of concentrated wort in the bag after the mash. A sparge isn't going to get all of that out. You HAVE to either be able to squeeze the crap out of it, or at least suspend it above the kettle for about 25-30 min. If not, you are missing out on all of that concentrated wort and your efficiency is going to suffer for it.
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Old 08-26-2011, 07:40 PM   #8
manicmethod
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Jul 2010
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Quote:
Originally Posted by TopherM View Post
Two suggestions:

1) Next time do a double mill. A fine crush is all good, but you are still going to miss a good % of the grains altogether. Mill, dump the milled grains back in, and mill again.

2) Did you do a really good drain of the bag? I know it would be extremely difficult to squeeze a 20lb grain bag, but you have to get the wort out of there somehow. In a 20lb grian bill, there is almost 1.5 GALLONS of concentrated wort in the bag after the mash. A sparge isn't going to get all of that out. You HAVE to either be able to squeeze the crap out of it, or at least suspend it above the kettle for about 25-30 min. If not, you are missing out on all of that concentrated wort and your efficiency is going to suffer for it.
I set the corona to grind finely, there were definitely not uncrushed grains, there was plenty of flour in fact.

The bag did sit above the kettle for probably 20 minutes, I normally press down with a pan lid but I didn't this time because of the small amount of room I had to work with.

 
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Old 08-26-2011, 07:48 PM   #9
seabass07
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Apr 2011
Brothell
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If you didn't stir enough, you could have had a lot of dough balls. That will kill efficiency. I've found that a finer crush will cause more dough balls requiring a lot more stirring and crushing of the dough balls.

 
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Old 08-26-2011, 07:51 PM   #10
SenorPepe
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Feb 2011
Madison, WI
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So....excuse my ignorance here, but why would you ever mash a regular beer for 8 hours?



 
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