This was my first all-grain BIAB after a few mini-mash BIAB beers that went well. Made a dunkelweizen with this grain bill:
5.5 lbs raw red wheat (breiss)
1.5 lbs munich 20l 2-row
1 lb. malted rye (breiss)
4 oz special b
4 oz chocolate malt (lhbs didn't have carafa ii)
Mashed in at 154 on the button at 1.25 qt/lb for 60 minutes. Lost about two degrees.
Then heated 2 gallons of water to 168, pulled grain bag and let it drain, then put bag into 168 degree water for 10 mins. Lost about 10-12 degrees over that time.
Gathered 4 gallons of wort (which was my goal) but only 1.052 SG when I was shooting for 1.068.
The question: did the sparging step cause the low SG due to the drop in temp? I squeezed the bag as much as I could after sparging, just didn't hit the gravity. Boiled as usual and just topped up enough water to hit my post-boil gravity regardless. Got about 4 gallons in the end at 1.052 SG.