My Brew In A Bag madness or methodology
I first want to get a total water volume required. I know from my past calculations that my grain will absorb about 0.5 gallons per pound of malt so that 11.5 X .05 = 0.575 gallons.
My batch size is 5.25 gallons.
Total w adidas football ater needed = 0.575 + 5.25 + 3 = 8.825. I measure 8.8 inches in my pot since 1 gallon for my pot. All of the water in the mash would give me 3 qts/ thickness, I can thicken this up a bit by doing a mash out sparge. I have found it makes things easier and gives me better efficiency when I do this so I normally do. I will save 2 gallons for a mash out so I put 6.8 inches of water in my pot and begin heating.
I use the 6.8 gallons of water in my water adjustment spreadsheet to find that I need the following salts:
1 3/4 tsp Chalk
4 1/2 tsp Epsom
4 3/8 tsp Baking Soda
6 tsp Salt
Yeah, my water is pretty void of minerals. I find it hard to adjust to a certain profile so I usually just adjust to meed the SRM then check the chloride to sulf adidas football ate ratio to fit the malty/bitter profile for the beer I am brewing.
I take the temperature of my grain and find out I need 162.5F for the 6.8 gallons of water plus grains to hit 156F mash temperature. I not critical on this step for this beer because it is just important to be above 152F.
Once I hit mash temperature, I dissolve the salts in a smaller bucket of the mash water and set it aside. I put wok grate in the bottom of the pot and hook my bag into the pot. I made the bag myself out adidas football of a voille fabric. Bag size is important, the pot should fit INSIDE the bag. I use office binder clips to hold the bag onto the pot. I can still put the cover on it then. I slowly pour the grains in and stir out all the dough balls. I pour the dissolved salt water in and stir again. I cover the pot then wrap it in an old comforter and set the timer for 90 minutes. I find 90 minute mashes give me good results. The first half hour or so I may stir the mash once or twice.
With about 15 minutes left in the mash, I move the kettle off the burner and onto a side table. I use the pot that came from my turkey fryer with the 2 gallons of water that I set aside for a sparge and heat it up to 170F+. I set the pot on the ground next to the burner and reset the mash kettle onto the burner again. Once the mash time is up, I unwrap the kettle, remove the cover, and unclamp the bag. I gather up the ends of the bag and begin to lift it out of the mash water. No pulleys needed. I handled a 23 mash before, it isn really too heavy. I begin to twist the bag to tighten around the grains and continue to hold it over the water. If I have a helper, I will have the burner on medium as I am draining. I keep twisting and holding until the stream is fairly low then quickly move the bag over to the sparge kettle. I dunk the bag in the sparge water a few times to make sure the hot water gets into the grain bed to knock the extra sugars out. I then do the twist and hold procedure again. I will then put the bag in adidas football to one of my fermenter buckets and dump the sparge water into the boil kettle and fire the burner up to high. I put a metal colander upside down into the turkey fry pot and put the grain bag ontop of that. I use a metal pan cover to squish the bag against the colander and twist and squeeze and reposition the bag and repeat until I can get any more liquid out. That wort goes into the kettle too and the grain bag goes into a 5 gallon round cooler with the end open for my sour mash two days later.
From this point on, the brew is like all other brews. I boil and add the hops at the required time. I chill. I transfer into my carboy, pitch the yeast, and ferment.
The beauty of BIAB is it can be so simple, by not sparging, just use all your boil water in the mash. But it can also be used for advanced techniques like decotion. See, you have a fired mash tun so you can decoct or step mash with the full volume of water by just lighting the burner. You can partigyle. You can minimash a large batch of partial boil beer.
BIAB is NOT a stepping stone to the cooler mash tuns. It is a legitimate alternative. The quality of beer is equal to the traditional sparge methods. There is some time savings. There is significant equipment cost savings. There is significant equipment space savings. The calculations are pretty simple. The concept is easy to grasp. You can get a high quality wort with high efficiency. You can do large batches (I done 11 gallon batches). You can do high gravity (you have a 15 gallon mash tun as opposed to a 5 12 gallon cooler). No stuck sparges. No grainbed channeling problems. No astringency issues. I heard there was a recent study that found the cloudy wort you get from BIAB is actually helpful to the yeast!
Do you know how much water was absorbed?
Check the mill of the grains, BIAB can be pretty well milled, I usually ask the online stores I buy from to double mill the grains.
Stirring in the beginning of the mash helps.
A mashout can help too, bring the mash up to 168ish and hold for 10 15 minutes.
And lastly, it could just be one of those times that a number of things lined up against you. Your next mash could be perfect.
I suggest copious not taking and take readings of everything you can as much as you can for your first few BIAB batches. Volume, gravity, temperature, etc. These notes can really help you dial in your process. I once took gravity and volume readings when I pulled the bag, when I added the gravity drippings from sitting in the colander, and then a few times as I squeezed the bag. Just to get some quantitative data for what I was doing. That how I found out my grain absorption and how much worth it was to squeeze the heck out of the bag. I usually get 80 85% efficiency and 0.05 gallons/ of grain with slight variance with high or low volumes of grain.
Try a few of these hints you next beer and if it improves keep doing whatever it was that worked. In the meantime, you can make adjustments post mash but pre boil to get closer to your desired beer.
Check your SG and volume post mash, you can boil longer to lower the post boil volume which will raise the SG of your wort pre ferment. Fiddle with your software to figure out IBU adjustments if you want.