Help diagnosing low OG in first and second AG - Home Brew Forums
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Old 11-14-2010, 09:24 PM   #1
sensibull
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Just finished my second AG and I thought I had the process down fairly well, but once again I got a much lower OG than expected (made Conroe's Mojave Red, should have been 1.056 or so, mine was around 1.041-1.042).

So, I'm pretty frustrated and don't want to have it happen again. Hoping if I describe my process someone might spot the points where I can increase my efficiency.

Steps

1. Buying the grain bill as specified and having my LHBS do the milling (i.e. not upping the grain bill, though I'm batch sparging. Should I?). Can't afford a mill at this point, but realize this might be an area to increase efficiency.
2. Been using Beersmith to calculate Strike and Sparge amounts. In this case, for about 10lbs of grain, I used 3.15 gallons for dough in and 4.3 gallons for sparging. Water is from a farmhouse well. Tastes great, maybe a little bit high in iron.
3. Dough it at 167, stirred, and mash temp evened out at 153.
4. Held mash temp at 152 for 60 min, as the recipe called for. Using a 10g rubbermaid with bazooka tube, per Flyguy's guide.
4. At 60 min. mark, vorlaufed a few pitchers of the first runnings, and then immediately drained the wort into my brew pot.
5. Sparged with 4.3 gallons at 172 degrees. Pour water in over a strainer. Now this is where I had problems. The temp of the grains + sparge water never hit 168. It only made it to 162 or so. Why? Only waited about 2-3 minutes**, vorlaufed again, and then opened the valve to collect the second runnings in the brew pot**. Collected a little over 6 gallons, with quite a bit still left in the mash tun.
6. Boiled for 60 minutes as normal, etc. etc.

Now, after a bit more reading, it seems the points marked with ** are where I made my errors, meaning I should let the sparge water sit longer and I should be draining the sparge water a lot more slowly. I also need to figure out how to properly mash out. Could those two things entirely explain my low OG?

Many thanks in advance for any advice offered.



 
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Old 11-14-2010, 09:41 PM   #2
Pick
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First, did you temperature correct your SG readings?

Second how does the crush from your LHBS look? Last one from mine had a lot of whole kernels in it. I should have run it through my Corona again.

If you come out low, you can always add some sugar or dextrose.


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Old 11-14-2010, 10:16 PM   #3
sensibull
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Quote:
Originally Posted by Pick View Post
First, did you temperature correct your SG readings?

Second how does the crush from your LHBS look? Last one from mine had a lot of whole kernels in it. I should have run it through my Corona again.

If you come out low, you can always add some sugar or dextrose.
I did temp correct the readings. Not sure I'm experienced enough to evaluate a crush, but I honestly didn't look at it too closely before poring it in the tun. Seemed OK, but I don't know.

I am considering adding a 1/2 lb. of dextrose at high krausen. Conroe (member here, recipe author) suggested against it, because it would probably make the beer finish too dry, I'd like the beer to have a little alcohol in it though .


 
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Old 11-14-2010, 11:20 PM   #4
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Generally, a poor crush is the cause of efficiency issues. Sometimes water chemistry plays a part.

Did you get roughly the same efficiency last time? What I'd suggest is figuring out your efficiency (Beersmith makes it easy) and just planning on that % for your future batches. My efficiency is always 72%- it's not good or bad, it's just what it is. If you plan your recipes based on your own efficiency, your beer will come out every time.

That said, I don't understand #5 about your sparge. Your batch sparging? But pouring through a strainer? I'm not sure I understand. Can you explain exactly what your process is? You can add hot enough water to get your grainbed to 168. For me today, that was 10 quarts of 187 degree water. (I did a 10 gallon batch today)
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Old 11-14-2010, 11:25 PM   #5
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Are you stirring after you add your sparge water? I have only done two AG brews so far, and I'm getting 77-81%. I stir for about two minutes after adding the sparge water.

I'm certainly no expert...just trying to help.

 
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Old 11-14-2010, 11:31 PM   #6
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Quote:
Originally Posted by RedHouse View Post
Are you stirring after you add your sparge water? I have only done two AG brews so far, and I'm getting 77-81%. I stir for about two minutes after adding the sparge water.

I'm certainly no expert...just trying to help.

I stir the heck out of the mash (2 or 3 times) and often let it sit longer than 60 minutes. I also stir the sparge and let it sit 5 minutes or so. I don't know if it makes any difference but I have consistently had at least the recipe OG sometimes more.

Just the way I do it, and I get good results.
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Old 11-14-2010, 11:42 PM   #7
sensibull
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Quote:
Originally Posted by Yoop View Post
Generally, a poor crush is the cause of efficiency issues. Sometimes water chemistry plays a part.

Did you get roughly the same efficiency last time? What I'd suggest is figuring out your efficiency (Beersmith makes it easy) and just planning on that % for your future batches. My efficiency is always 72%- it's not good or bad, it's just what it is. If you plan your recipes based on your own efficiency, your beer will come out every time.

That said, I don't understand #5 about your sparge. Your batch sparging? But pouring through a strainer? I'm not sure I understand. Can you explain exactly what your process is? You can add hot enough water to get your grainbed to 168. For me today, that was 10 quarts of 187 degree water. (I did a 10 gallon batch today)
Something I read somewhere suggested it wasn't a good idea to just dump the whole amount of sparge water straight into the mash tun -- that it would create a channel through the grain and not pick up enough sugars/create adequate wort along the way, so I poured in the sparge water through a strainer to deflect/decrease the impact of the water, so to speak. Is that not proper technique? I guess if I was letting the sparge water sit longer, as I should be, it wouldn't matter so much...

I also suppose I was hesitant to just keep adding more hot water (to hit 168) because I thought that would water down the wort and exacerbate my low gravity problems.

I just played around with Beersmith a bit and figured out how a scale a recipe for different efficiencies. That will certainly help me in the future. Thank you.

 
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Old 11-14-2010, 11:44 PM   #8
sensibull
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Quote:
Originally Posted by RedHouse View Post
Are you stirring after you add your sparge water? I have only done two AG brews so far, and I'm getting 77-81%. I stir for about two minutes after adding the sparge water.

I'm certainly no expert...just trying to help.
Thanks for the tip. I only stirred at dough in, not during the sparge.

 
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Old 11-15-2010, 03:10 AM   #9
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Quote:
Originally Posted by sensibull View Post
Something I read somewhere suggested it wasn't a good idea to just dump the whole amount of sparge water straight into the mash tun -- that it would create a channel through the grain and not pick up enough sugars/create adequate wort along the way, so I poured in the sparge water through a strainer to deflect/decrease the impact of the water, so to speak. Is that not proper technique? I guess if I was letting the sparge water sit longer, as I should be, it wouldn't matter so much...
I would think that channelization would have a bigger impact if you were doing a continuous sparge as opposed to a batch sparge. I dump my batch water in, stir it up, let it sit for 5 mins or so, vorlauf, then drain.
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Old 11-15-2010, 03:12 AM   #10
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Quote:
Originally Posted by sensibull View Post
Something I read somewhere suggested it wasn't a good idea to just dump the whole amount of sparge water straight into the mash tun -- that it would create a channel through the grain and not pick up enough sugars/create adequate wort along the way, so I poured in the sparge water through a strainer to deflect/decrease the impact of the water, so to speak. Is that not proper technique? I guess if I was letting the sparge water sit longer, as I should be, it wouldn't matter so much...

I also suppose I was hesitant to just keep adding more hot water (to hit 168) because I thought that would water down the wort and exacerbate my low gravity problems.

I just played around with Beersmith a bit and figured out how a scale a recipe for different efficiencies. That will certainly help me in the future. Thank you.
Quote:
Originally Posted by tippetsnapper View Post
I would think that channelization would have a bigger impact if you were doing a continuous sparge as opposed to a batch sparge. I dump my batch water in, stir it up, let it sit for 5 mins or so, vorlauf, then drain.
Right. If you're batch sparging, just dump it in and stir like a madman. You can add water, even boiling water, to get your grain bed to 168 during the first addition of sparge water. That might help you quite a bit.


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