First BIAB recipe - critique

going for my first BIAB. We have 3 pots, 2 - 12.5 gallon, 1 - 5 gallon.
Let me know what you think about this water/grain ratio.

9 Gallon Batch
Grain Bill:
20 lbs Rahr Pilsner

30 quarts / 7.5 gallons mash, water at 161F. 20 lbs of grains(80F) will lower it to 152. sit for 60 mins.
Pull bag out, let drip or squeeze out excess water. then Dunk sparge in 2nd pot -
18 quarts / 4.5 gallons sparge @ 170F sit for 10-15 mins

Combine both pots, boil 90 mins, start hop additions at 60 mins

1 oz summit @ 60
2 oz Centennial @ 15
2 oz Cascade @ 10
1 oz Galaxy @ 5
1 oz Citra @ 5
1 oz Citra @ 0

1 oz Galaxy dry hop
1 oz Cascade dry hop

I do 5 gal BIABs, but my temp always drops about 5 degrees when mashing in, not close to 10...I would think that ours would be similar since you've also got about twice the water (or thermal mass) as me. Just being sure you dont accidently mash much higher than you wanted

The hop schedule is whatever you prefer. I like to omit almost all additions save for a 60min and opt for a massive flameout addition followed by a hop steep. I;d definitely recommend at least moving the 5min additions to 0min and do the hop steep with them. I think youll get more flavor out of those ozs than traditional 5rmin addition

sound good
for the mash in temp i used brewers friend calculator - http://www.brewersfriend.com/mash/
I'll keep some hot and cold water on hand to adjust it.

i was about 2 gallons short in the end from boil off, grain absorbtion, etc. next time will go with more water upfront in the mash and sparge

hopbrad said:

i was about 2 gallons short in the end from boil off, grain absorbtion, etc. next time will go with more water upfront in the mash and sparge

Click to expand...

Since the main thing you are boiling off is water, add it back if you need to or else your 5% beer may become a 7% beer, not exactly what your recipe intended.