Might have to go BIAB for tomorrow's brew due to grain bill size

So my grain bill is huge and wont fit in my mash tun (5 gallon cooler). I've basically got that method mastered but I haven't followed BIAB or really looked into it.

My kettle is 7 gallons so I can sure fit all of the grain into it with a good volume of water. I can pick up those paint strainers from home depot.

What is the best way to maximize efficiency with this method? I have my grain bill calculated at about 75% efficiency, I'd like to achieve that or even go slightly over. I will sit there and stir it with a light flame on it to keep temp for 75 minutes if I have to. I will be putting a pasta strainer on the bottom of my kettle to avoid bag melting/scorching.

Hopefully you have a good crush. That will help. I usually re-heat every 15 minutes and stir the whole time it's coming back up to temp. It will usually drop 2-3 degrees during each 15 min interval. Lots of BIABers will insulate the pot so they can let it go undisturbed for the entire mash, but I like to think the intermittent stirring helps up the efficiency a bit. I could be all wet on that, though. Also, do a dunk sparge if you can. Just a gallon or so of room temp water in a 5g bucket will do it. Then squeeze the bag like it owes you money. Do all that and you should hit 80% or better.

I get 75%+ by getting my strike water to temp, putting the grains in the bag (making sure they are loose and I stir like crazy to wet all of them and break up clumps). I actually eat the strike water a degree or two high so I can stir more.

Then I put it in my oven set to 170 and turned off. I stir every 20 minutes. Then I sparge as much as possible to get my pre-boil volume. I don't put in any "clean" water, all sparge water.

This is going to weigh WAY too much to go in my oven rack. I don't want to risk it as I am a renter and that oven is crazy expensive/upper-class.

Here is my plan for "sparging". One kettle will have about 4.5 gallons of water at 150-153 degrees, this will be the primary mash. Give it 60 minutes at this temp, stirring intermittently and adjusting temps. Then for ten minutes, heat it up to ~167, stir vigorously.

I hope this will be good enough, I will be letting it drip into another pot and I'll add that to the mash.

It is about 14lbs of grain for a 4 gallon brew. Pre boil amount will be about 6 gallons. 90 minute boil and .5 gallon lost to trub.

How much water will you be sparging with? I'm guessing it will need to be around 2 gallons.

LLBeanJ said:

How much water will you be sparging with? I'm guessing it will need to be around 2 gallons.

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Yeah, that's about right. I could put the bag in my mash tun, pour the 2 gallons of sparge into the grain, slosh it around, let it sit for 15 minutes, then lauter it and add it to the kettle while the rest is heating up?

I think most of the extraction will happen in the initial 70~ minutes of hard mashing.

I could always do two mashes but that would really take all day.

Your sparge plan sounds fine.

LLBeanJ said:

Your sparge plan sounds fine.

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Will my wort be clean? I'm not sure what type of filtration those bags offer but I dont want to boil any husk. Maybe I will pour it through a superfine mesh strainer before I boil.

I think the bag will contain the husks okay. If not, then go ahead and strain it.

kharper6 said:

Will my wort be clean? I'm not sure what type of filtration those bags offer but I dont want to boil any husk. Maybe I will pour it through a superfine mesh strainer before I boil.

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Why not? If your wort pH is where it should be you could boil a whole lot of husks without a problem. Look at what a decoction does.

My paint strainer doesn't let any husks through even when I squeeze hard. Some of the grain flour does but that settles out at the end of fermentation anyway leaving my beer clear.

I squeeze the bag in a colander by pressing on it with a plate. No gloves, no burns, plenty of pressure. This works well with either dunk or pour sparging.

Once i've started the mash, i wrap a sleeping bag around the pot and put a blanket over the top. Temperature holds very well.