Missing OG - any ideas?

[SantaClaus]

Quick question - I'm brewing right now and have missed my pre-boil OG.

Grain bill =
12lb 2-Row
1lb = Biscuit
1lb = Wheat
.5 lb Crystal 60L
.5lb = Munich
.5 = Special B
TOTAL = 15.5lb

step mashed with 5.8gallons @ 122 (30min) -then rose it up to 154 (30min), mashed out at 168), fly sparged and collected 7.25gal for 90min boil.

Target pre-boil OG was 1.070 and I ended up with a 1.050.

What's the deal, any ideas? Also added 1lb of candi sugar to boil, so I'm sure it will increase a bit, but BeerSmith said I should have a 1.070 pre-boil, which I don't.

I miss my OG often, but can't figure out why? grain crush?

Thanks guys and girls

~Enjoy the long weekend.

 

[beaksnbeer]

Crush could be temps might be off check thermometer

 

[usfmikeb]

You sure it's supposed to be pre-boil for 1.070? If it's post-boil at 5 gallons, it would be 1.072.

I don't have beersmith, so I can't run it.

 

[usfmikeb]

Just looked at a chart I typicall use, and the 12 pounds of 2 row would yield 1.053 at 85% efficiency. Add in the rest of the grains you're using, and it could be 1.070 at 85% efficiency. Looks like you're probably hitting 60% efficiency.

Temp could be one issue. I typically do a 60 minute mash, maybe try doing a longer one next time.

 

[SantaClaus]

I almost never remember to take pre-boil gravity, but did today...

On the BeerSmith Brewsheet it says pre-boil gravity should be 1.070, with an estimated final of 1.090. But as I mentioned, I'm only at 1.050 pre-boil.

I brewed yesterday and hit the target O.G, but that is a rare event, more often then not I'm off. It's driving me nuts.

Didn't adjust the mill since then and I felt like my temps were even better today.

 

[yodalegomaster]

The most common problems with efficiency are PH is too high for the mash water, and or not allowing enough time in the sparge phase to fully dissolve. Grain crush can effect it but most people over crush not under crush, the under crush is what decreases the efficiency.

 

[SantaClaus]

Thanks for the responses - I ended up with a post-boil OG of 1.073, which is alright, but not the 1.090 calculated.

This is only the 3rd batch on the new stand, single tier Brutus-style, sans the automated temp control. I'm still getting a feel for it. My temps have been a little wonky. The last 2 batches were better than the first.

The MLT has 3gallons of deep space in it and I think that might be contributing. It was a slow sparge (45min-1hr), but temps might have been too low....

So it could be a few things;
grain crush
water PH
Temp
Length of sparge

I'll try to systematically narrow it down over the next few sessions. It's driving nuts.

Thanks for the responses folks - enjoy the holiday.