Second Beer from Third Runnings??? Help Quick

Berwing a Black IIPA tomorrow morning. Recipe follows:

Recipe Specifics
Batch Size (Gal): 5.50 Wort Size (Gal): 5.50
Total Grain (Lbs): 22.13
Anticipated OG: 1.099 Plato: 23.53
Anticipated SRM: 26.4
Anticipated IBU: 119.0
Brewhouse Efficiency: 70 %
Wort Boil Time: 70 Minutes


Pre-Boil Amounts
Evaporation Rate: 15.00 Percent Per Hour
Pre-Boil Wort Size: 6.47 Gal
Pre-Boil Gravity: 1.084 SG 20.25 Plato


Grain/Extract/Sugar
% Amount Name Origin Potential SRM
67.8 15.00 lbs. Pale Malt(2-row) America 1.036 2
18.1 4.00 lbs. Munich Malt(2-row) America 1.035 6
6.8 1.50 lbs. Rye Malt America 1.030 4
4.5 1.00 lbs. Crystal 40L America 1.034 40
1.7 0.38 lbs. Carafa Special Germany 1.030 475
1.1 0.25 lbs. Chocolate Malt America 1.029 350
Hops
Amount Name Form Alpha IBU Boil Time
1.00 oz. Columbus Pellet 14.00 37.2 60 min
1.00 oz. Centennial Whole 11.20 27.8 60 min
1.00 oz. Columbus Pellet 14.00 28.6 30 min
1.00 oz. Centennial Whole 11.20 21.4 30 min
1.00 oz. Amarillo Pellet 7.50 4.0 5 min
1.00 oz. Centennial Whole 11.20 0.0 Dry Hop
1.00 oz. Amarillo Pellet 7.50 0.0 Dry Hop

I'm mashing at 1.27 qts/lb, sparging with 1 qt/lb.

How can you calculate third runnings OG? Do I just wait, collect it and measure then?

Any help or feedback welcome. Thanks

I wouldnt try to calculate third runnings but maybe start here to get an idea of where you will end up

http://brewingtechniques.com/library/backissues/issue2.2/moshertable.html

doesn't seem to me like third runnings would be well suited to a beer by itself. My grain bed run pretty clear after a slow two sparges.

Interesting chart linked above, simply put the 2nd sparge will yield about half the gravity assuming the two batches are similiar volume. So in theory, if your batch 1 is 1.084, batch 2 should be around 1.042. Maybe a tad more if you run off twice for the second beer.

Personally, I'd collect the wort for the IPA, then measure what you're still getting from the third runnings. If they're below a certain level (I want to say 1.02 or so), I'm pretty sure you can run into issues with tannin extraction. You might want the second beer to be a half-batch so that you don't dilute it any more than you absolutely need to.

I think tannin extraction is 1.012-1.010

but i think the heat has more to do then the gravity as if you get your grain bed above 170

but how did the brew turn out?

the_bird said:

Personally, I'd collect the wort for the IPA, then measure what you're still getting from the third runnings. If they're below a certain level (I want to say 1.02 or so), I'm pretty sure you can run into issues with tannin extraction. You might want the second beer to be a half-batch so that you don't dilute it any more than you absolutely need to.

Click to expand...

This is kinda my plan, especially after looking at the mosher table. The tannins are definitely a concern. Right now, I have 2.2 qts running through each lbs of grain and as a rule, I try to limit it to no more than 3.3 which would leave a very small quantity.

It was really an after thought. Maybe I'll plan ahead better next time. Ray Daniels has a section in DGB that goes into parti-gyle brewing.