Extremely Low Gravity

[matthewjamesstone]

Hello all,

I just attempted my first all grain (and likewise, this is my first post).

I was doing an English Pale Ale, and it called for 9 lbs of grain...
We got our water up to around 165, and mashed for an hour (the water temp settled to about 156). We used roughly 5.5 gal of water, which may be slightly high...

Drained slowly and got our sparge water up to about 160. Sparging took about half an hour...

Checked the pre-boil gravity. 1.008. Yikes. Granted, the temp was about 150, but 1.008? The target was about 1.034.

Did our boil (hour long), cooled down the wort to 68 degrees. Took another reading. 1.010. Our target was 1.036...

My question is, what would account for such an enormously low OG?

Our water temp was in the ballpark, our volume was fairly close...I'm a bit frustrated and baffled by the results.

Anybody have any insight?

Thanks!

 

[mbird]

There could be a number of reasons for the low gravity. Check to make sure your instruments are calibrated and correct. The crush of the grain will have an effect, the temp. of the sparge water should be 170f., etc.
Taking a reading from liquid at the top of the volume could be the problem also. Did you stir the pre-boil wort thoroughly before taking a sample? Same with the cooled wort. The heavy sugars tend to be at the bottom of the pot and less at the top where you take your sample.
mark
Beer Diary...

 

[Yooper]

Was the grain crushed? It sounds like you got next-to-nothing out of the grains.

 

[Laughing_Gnome_Invisible]

Was the grain crushed? It sounds like you got next-to-nothing out of the grains.

Yeah, When I read pre-boil was 1.008.....That was a real Whaaat!!?? Moment. surely even uncrushed grain could do better.

 

[giligson]

Its a little late now for this advice but:
If you taste your spent grain at the end of the sparge, there should be no residual sweetness (it should all have been rinsed away) Furthermore, you may also want to do an iodine test to see if your starch had been converted in the first place.

 

[matthewjamesstone]

Yeah, I remembered the iodine test a bit too late. Such is life...

I stirred everything quite well...I took my samples from the bottom with a thief, so that shouldn't have been an issue.

I'll talk to the homebrew store people who crushed the grain...

I did taste the grains afterwards. I can't recall a sweetness, but I wasn't looking for it either.

I expected to be in the relative ballpark. Not, .025 points off though!

 

[Yooper]

What was the grain you used?

You should have used about 11.25 quarts (approx 2.75 gallons) in the mash. Using 5.5 gallons would have been too thin, but you still should have got some sugars out of the grain. Another thought is that if your thermometer said 156, it may have actually been hotter than that, and you may have denatured all the enzymes when you mashed in.

Are you certain that your thermometer was accurate? And why did you mash in with twice as much water? If your grain was actually crushed, I'm thinking that the high ph mash (due to too much water) and the high temperature "killed" the enzymatic action.

 

[matthewjamesstone]

That is certainly helpful. I've read that anywhere between 1.25 and 2 quarts per lb should be suitable. I was using English Pale malt...which, at the high end, would have put me a gallon over...

I'm not sure the thermometers we've been using are the greatest. We're going to invest in a quality one shortly. Hopefully that will help things out...

But that explanation has been the most likely that I can think of so far. Thanks for the help...

 

[matthewjamesstone]

So I found out the problem. The old thermometer were were using was reading about 40-50 degrees hot. Whoops.

 

[Bobby_M]

Hmm yeah, mashing at 115F is not going to do any conversion.

 

[ericm]

whoa, that is WAY off!