Author Topic: Just started all grain - have some Q's about a low OG  (Read 1551 times)

Offline madscientist

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Just started all grain - have some Q's about a low OG
« on: August 19, 2013, 12:18:34 PM »
Hello AHA.  It's been a while since I posted here, but I have been on a brewing hiatus for the past few months while my wife and I prepared to move into our first house.  Since it is a brand new house, and she didn't want me brewing in the kitchen, she gave me the full support to convert from extract and partial mash to all grain.  This weekend i brewed my first two batches - Two hefeweizens for an upcoming party. 

The brew day went as planned and I didn't have any more troubles than expected for working with a new set up, however, on both batches my OG came out significantly lower than anticipated.  Beersmith told me 1.055 and I got around 1.043-1.045 on both batches.  While it's not a huge concern to me, I would like to know where I can improve my process. Here is what I did:

Recipe:
10lb grain (6# wheat, 3# pils, 1#munich, hefty scoop of rice hulls - figure 0.5 lb) - Grain was crushed by my LHBS.
1 oz German Hallertauer @ 60 min

Mash @ 1.4 qt/gal for 60 min - 152 deg F (14.00 qt)
Batch sparge with 4.2 gal of water - 168 deg F
Total boil volume = 6.5 gallons.  Boil 60 min, chilled to 70 and pitched a 1.2L starter of WY 3068
Anticipated OG: 1.055

So as I said before, my OG came in around 1.043-1.045 for each batch.  While 152 was my target mash temp, I only ended up hitting 149-150.  I didn't preheat the mash tun, and I think I could heat my strike water up to a higher temp.  (I only was going to 164). 

After the 60 min mash, I recirculated about 2 quarts of wort and drained the tun into the kettle.  Added my sparge water (at 168), mixed thoroughly (at least what I considered thorough), recirculated another 2 qts, and drained for a total boil volume of 6.5 gallons.  I had no stuck sparges, but there was some liquid left in the bottom of the tun (expected dead volume?)

My mash tun is a 52qt cooler with SS Braid. 

I believe my lack of OG can be attributed to the mash but I was wondering if anyone had any suggestions on what I could change.

Edit: I did not see a previous post on almost the same topic, so I'll read through that but feedback would be appreciated nonetheless.
« Last Edit: August 19, 2013, 12:20:45 PM by madscientist »
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Re: Just started all grain - have some Q's about a low OG
« Reply #1 on: August 19, 2013, 12:31:24 PM »
What was your overall efficiency setting in beersmith?

1.4 qt/lb is a little thick for me I might bump that up closer to 1.75-2qt/lb.

without knowing what your efficiency was it's hard to say if there is a major problem. I personally would not expect to get 1.055 out of 10 lbs of grain but I get fairly low efficiency and there are many who would.

Some assumptions I am making:

the actual total volume post boil was 5.5 gallons.
The average pppg for the grist was 36

36*10(lbs of grist)= 360 points/5.5 gallons = ~65.5. So 100% efficiency would be 1.065ish.  I would guess beer smith is set to around 85% efficiency and you got around 74% pretty good actually
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Offline redbeerman

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Re: Just started all grain - have some Q's about a low OG
« Reply #2 on: August 19, 2013, 12:34:40 PM »
Welcome back!  I would guess first that the low OG was caused by inadequate milling of the grains.  Wheat malt is smaller than barley, has no husk and may not have been well crushed if your LHBS ran it through the same mill as the barley malt.  I have run into this myself, even when milling it at home.  It pays to double mill wheat malt or adjust the mill settings a bit tighter.  Good luck on your new home!

BTW  going with 36 points/lb.  your efficiency was more like 66-69%.  Not bad for your first time out, but I would still check the crush next time.
« Last Edit: August 19, 2013, 12:43:52 PM by redbeerman »
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Offline madscientist

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Re: Just started all grain - have some Q's about a low OG
« Reply #3 on: August 19, 2013, 12:51:25 PM »
Thanks for the quick replies.

I will check my settings in Beersmith and report back.  This may be a dumb question - Doing extract and partial mash even I never really considered efficiency since adding LME/DME usually got me to within a point or two of my anticipated OG, but now that it looks like it is important how do I calculate it?

Regarding grain crush:  I want to believe my LHBS guy is pretty good, but I could see him milling the grain incorrectly.  I wasn't there when he did it.  I usually e-mail my order in and pick it up on my way home from work.  Will definately look into this more.

I have a high tech wooden volume stick I made, so I will have to remember to measure my post-boil volume and grain absorptions as well next time out, but I think 5.5 gallons is a good estimate.  Fermenter was at the 5 gal mark, and there was some left in the kettle with hop trub and break material.
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Offline kramerog

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Re: Just started all grain - have some Q's about a low OG
« Reply #4 on: August 19, 2013, 01:10:07 PM »
The unnecessary use of rice hulls can also reduce efficiency.  You indicate using "wheat" which I assume means wheat malt.  My experience for my system is that wheat malt does not lead to stuck sparges.  Flaked wheat which has high amounts of beta-glucans unlike wheat malt can lead to stuck sparges.
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Offline AmandaK

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Re: Just started all grain - have some Q's about a low OG
« Reply #5 on: August 19, 2013, 01:12:58 PM »
I will check my settings in Beersmith and report back.  This may be a dumb question - Doing extract and partial mash even I never really considered efficiency since adding LME/DME usually got me to within a point or two of my anticipated OG, but now that it looks like it is important how do I calculate it?

Regarding grain crush:  I want to believe my LHBS guy is pretty good, but I could see him milling the grain incorrectly.  I wasn't there when he did it.  I usually e-mail my order in and pick it up on my way home from work.  Will definately look into this more.

I have a high tech wooden volume stick I made, so I will have to remember to measure my post-boil volume and grain absorptions as well next time out, but I think 5.5 gallons is a good estimate.  Fermenter was at the 5 gal mark, and there was some left in the kettle with hop trub and break material.

You are correct, there is a set amount of fermentables in LME/DME and there's not much you can do except to screw up your volumes to mess that one up.

There are many, many variables to efficiency. If you can stand some nerdery, try taking a look at Kai's take on it: http://www.braukaiser.com/wiki/index.php?title=Understanding_Efficiency

For something a little less in depth, try this one: http://www.howtobrew.com/section2/chapter12-5.html

Another quick point about wheat malt is that the kernels can be a smaller size that malted barley. You may need to have it milled twice at the LHBS to get a good crush on their setting.
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Offline mtnrockhopper

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Re: Just started all grain - have some Q's about a low OG
« Reply #6 on: August 19, 2013, 01:14:00 PM »
Raising your sparge water temp might help get those last bits of sugar dissolved too. Using 168F water will result in a mash temperature well below 168F. Denny's batch sparge instructions say ~180F water.
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Offline HoosierBrew

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Re: Just started all grain - have some Q's about a low OG
« Reply #7 on: August 19, 2013, 03:13:29 PM »
+1. I sparge ~ 185 -190F, which raises the grain bed temp to ~ 168.  As said, getting a double crush from your LHBS is huge - it helped me go from ~ 68-70% efficiency to consistently over 80%.  And be sure your volumes are spot on. You don't need to be much over (or under) your target kettle volume to throw your OG off noticeably.
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Offline dmtaylor

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Re: Just started all grain - have some Q's about a low OG
« Reply #8 on: August 19, 2013, 03:37:10 PM »
My 2 cents: It's between one or two things.

1) The crush might not have been hard enough.

2) Based on gut-feel, 10 lbs grain for 5.5 gallons of 1.055 beer seems on the light side.  I would expect more like 11-12 lb for the standard efficiency of ~75%.  Not sure how you got to just 10 lbs?!  Was your Beersmith calculator assuming you'd have 80-85% efficiency or something?!
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Offline jeffy

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Re: Just started all grain - have some Q's about a low OG
« Reply #9 on: August 19, 2013, 06:11:03 PM »
One more thing:  you're in a new house and may not know all about the water.  pH has an effect on the mash and with the light colored grains you may have to add some acid to acidify it to the proper pH.
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Offline In The Sand

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Re: Just started all grain - have some Q's about a low OG
« Reply #10 on: August 19, 2013, 06:32:33 PM »
I agree with most everything said. I will say a big +1 to using a thinner mash (I use 1.8 qts/lb and saw a big jump in efficiency after previously using about 1.25-1.4 qts/lb).  Also a big +1 to using 185* sparge water. Don't sweat it over a few points though. Make sure all your volumes were measured correctly. You probably got better than average efficiency after all.
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Offline madscientist

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Re: Just started all grain - have some Q's about a low OG
« Reply #11 on: August 20, 2013, 09:31:15 AM »
Some great advice, and I am going to take all of this into account next batch.

1. I didn't have a chance to check what Beersmith was set at for efficiency.
2. I used 10lbs because I was under the impression 5-5.5 gal batches generally used 8-10 lbs of grain (and I'll admit, 10lbs was an easy number to work with).  From what I've read here, I need to adjust that weight for effiicency. 
3. I will try a thinner mash. 
4. Rice hulls - Again, I was under the impression they should be used for mashes with wheat, but I realize now that I may have read that for flaked wheat/rye etc.
5. I will definately start keeping (better) track of volumes etc.
6. I did a lot of research on the water with mineral content/chlorine, but I didn't really consider pH.  Again, being used to all grain and partial mash brewing I was never really concerned with it, especially since I used bottled water.
7. Temperature control - Figuring out my system so I get the proper temperatures for mash and sparge.  (Using 185 deg as opposed to 168 deg for sparging and preheating my mash tun).
8. I will ask for a second crush on my grains.

Further, I've checked out the howtobrew resource for efficiency and it definately helps me understand a lot more.

I really appreciate the feedback. 
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Offline mankeb

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Re: Just started all grain - have some Q's about a low OG
« Reply #12 on: August 20, 2013, 07:24:47 PM »
When I mash in my 10 Gal Rubbermaid cooler doing single infusion mashes I add the strike water first and adjust to get my target strike temperature prior to adding crushed grains.  This preheats the cooler.  Regardless of what Beersmith says for my system this temperature is usually about 12F above my target mash temp. (Experience will tell you what you get with your system)   I realize many suggest adding water to grains but I have not had any problems with doing it this way as long as I stir  with a long SS spoon until fully mixed.  I also batch sparge ala Denny and use 178F water and usually hit 168F. (Thanks Denny!)

Only having a 10 Gal mash tun limits my total water volume for both water additions to about 6.5 Gal water for a grain bill of up to 18#. This limits my water to grain ratio to about 1.15 Qts / pound unless I'm doing a decoction where I only do 1 initial water addition prior to final batch sparging.  Beersmith really helps me track what I do on each batch and I adjust each future batch to the efficiency I got in the previous batch and use enough grain to reach my target OG with that efficiency.  My efficiency varies based on the beer style.  High wheat malt bills usually results in lower efficiency for me... maybe due to the crush issue discussed. I am going to try double crushing the Wheat only next time.  I have also heard some do a "wet" crush and get good results with wheat malt.  I also use about 1/4#-1/2# of rice hulls when using any wheat malts or adjuncts.

Keep brewing and keep good records and you can get your AG system dialed in and you should see better results each time.

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Offline madscientist

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Re: Just started all grain - have some Q's about a low OG
« Reply #13 on: November 11, 2013, 10:27:37 AM »
Hey,

Just wanted to give everyone an update and thanks for the advice.  This past saturday (11/9) I did my second all grain batch and hit my anticipated OG right on the money. 

1. Amount of grain went from 10 lb to 13 lb
2. Mashed at 1.8 qt/lb
3. Preheat mash tun - Hit my target mash temp on the nose (152)
4. Heat sparge water to 180-190 deg F instead of 168.

I didn't get the grains double crushed because I forgot, but I really couldn't have asked for a better brew day, so thanks!
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