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Old 07-07-2008, 11:00 PM   #1
Jun 2008
Posts: 59

This is a long post as I want to give you as much info as possible.

I have just brewed my third all grain batch and all three have had low OG by app. 10-15. (Batch#1 Meas:1035 vs. Recipe:1045, Batch#2 Meas:1038 vs. Recipe:1050, Batch#3 Meas:1045 vs. Recipe:1060). My software tells me I only have 55-60% mash effectivity (ProMash)....

All grains have been crushed by the store where I bought the grains.
I am (for batch #2 and #3) using PH5.2 so PH should not be a problem.
My mash temperature is right on the money (150-155), checked by two thermometers (analog & digital, app. 6F difference between them, so I take the average and aim for 152F)
Gravity is checked by hydrometer and temperature adjusted, usually at around 100F.

Here is the flow: (5-6Gal batch)
1. 5 Gal mashwater is heated to 175F
2. Added to the grains in the mashtun (10Gal round Cooler w. domed steel falsebottom)
3. Added 1tbsp. PH5.2, stirred and temperature adjusted
4. Usually I stirr at the 30min mark as well
5. I heat app. 4 gal og sparge water to 175F
6. After 60 mins, recirculation, I then add the spargewater 1-2qt at the time and try not to disturb the mash. I usually keep at least 2-3 inches of water over the grains. I even have tasted the grains to taste if there is any sugar left, but they do not taste sweet at all after the mashout.

All my brews have been low, but fermentation i lively and the beer taste is great. I have checked the hydrometer w. regular water and with a 1050 suger solution and it looks ok.

I have read several books and searched forums to find a solution. Only thing I can think of right now is to try batch sparging instead of flysparging.

If anybody has an idea what to try I would much appreciate it.

Hommel HomeBrew

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Old 07-08-2008, 12:18 AM   #2
Feb 2008
Posts: 101
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Most people I have read experience a nice jump in efficiency by grinding their own grain. I know my crush is finer than a homebrew shop crush. Look into a Barley Crusher or some kind of mill that will crack the grain without shredding the husks.

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Old 07-08-2008, 12:28 AM   #3
xamers's Avatar
Apr 2008
Omaha to Japan
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What water are you using?

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Old 07-08-2008, 12:29 AM   #4
SporkD2's Avatar
Jun 2008
San Antonio, Texas
Posts: 740
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water or crush. If you LHBS is like mine, they crush a lot less fine because they want u to buy more grain

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Old 07-08-2008, 12:38 AM   #5
FlyGuy's Avatar
Jan 2007
Calgary, Alberta
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Any chance you could post a nice close-up photo of your crushed grain? I am betting it is a really coarse crush that is the cause of your troubles.

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Old 07-08-2008, 01:04 AM   #6
ohiobrewtus's Avatar
Nov 2006
Posts: 7,785
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Originally Posted by maho View Post
1. 5 Gal mashwater is heated to 175F
Why so high on the strike water? I heat mine up to 12-14F higher than my mash temp. By the time I transfer and the insulation in the cooler heats up I'm 9-10F above my mash temp and I dough-in.

I'm not suggesting that this is a source for the issue that you brought up, it just stood out to me when I read your post. As others have already suggested, the first place that I would look is the crush.
Originally Posted by the_bird
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Old 07-08-2008, 01:13 AM   #7
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Yooper's Avatar
Jun 2006
UP of Michigan, Winter Texan
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What jumped out at me is the method you're using to follow a desired mash temp. Averaging two inaccurate thermometers isn't going to get you the temperature you desire. Calibrate your thermometers in ice water, and see if either are accurate. For decent results with AG brewing, a good accurate thermometer is a necessity.
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Old 07-08-2008, 01:16 AM   #8
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Aug 2006
Whitehouse Station, NJ
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How long do you take to run the sparge water through? 60 minutes? I'd give batch sparging a go anyway because anything is better than 60%.
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Old 07-08-2008, 03:33 AM   #9
Jun 2008
Posts: 59

Thanks for all the suggestions.

The grains I have been using have been:
Batch#1: Bumber Blond from Mountain HomeBrew, Kirkland WA. Was also crushed here
Batch#2: HefeWeizen from MoreBeer, came crushed as well
Batch#3: Selfmade Pale Ale recipe w. 12lbs of grain, bought and crushed in Mountain HomeBrew

My water is filtered tapwater (Culligan D-20 filter). Can it be low calcium? Bare in mind that I am adding ph5.2 from MoreBeer.

I usually hit the mash temp quite well. Usually I am a bit hot, and I add cold water to get the temp down. I try to use at least 60mins for the mashout.

My analog thermometer will not go to 32F in ice water or 212F in boiling water so it is hard to calibrate. It is a cheap thermometer from MoreBeer. I have a digital (sugar thermometer, for making candy) which seams quite accurate in ice water and boiling water, but of course it does not say anything about the 150F accuracy.

My thinking is that if the mash is too hot, I should get ok OG, but end up with a sweet low alc. beer due to the dextrins. But my beer is not sweet and ferments well. So thinking that it might be too cold instead I have tried to hit the higher end of the mashtemp (152-155).

Please keep the suggestions coming! Again thanks to all for their contributions!

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Old 07-08-2008, 03:33 AM   #10
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ajf's Avatar
Oct 2005
Long Island
Posts: 4,646
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First, your thermometers differ by 6 degrees. Find out which is wrong, and don't use it, replace the batteries, or recalibrate it. A thermometer in iced water should read 32. Boiling water at sea level should read 212 - subtract 1 degree F for every 500 feet above sea level.
Second, how long do you take to sparge? As Bobby said, you need about 60 minutes or greater for fly sparging.
Third, You either have a mash problem, or a sparge problem (or both). You could use an iodine test to check for incomplete conversion in the mash. To check your sparge efficiency, after you have finished, give the sparge a good stir and wait for 10 minutes. (You may have to add some extra sparge water if your grain bed is very stiff), Then drain enough from the grain bed to take a gravity check. If the gravity of these runnings (after cooling) is much above 1.010, then you have a sparging problem (probably channeling as a result of sparging too fast).


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