BIAB with thick mash (1.2qt/lb)?

[slcdawg]

I've been doing 5gal BIAB batches in a turkey fryer (7.5gal) for a year with great success. All of those batches have had grain bill of <15 lbs with a mash thickness between 1.7-2.2 qt/lb.

I want to brew an imperial stout with a grain bill of 19.4 lbs. Using rackers the max thickness I can mash in this pot is 1.2 qt/lb (and that will be tight).

Will a thick mash cause problems? Should I consider scaling the recipe down? Anyone done a high gravity 5 gal batch in a 7.5gal turkey fryer?

Thanks for any input.

 

[The_Bishop]

Your efficiency will probably take a hit, as far as I have been reading. Haven't tried any grain bills that high.

 

[agrazela]

You could do it in two halves. I did an AG BIAB barleywine this way recently, splitting it because all I have is a 5gal kettle.

 

[benco]

You can mash longer or do a back to back mash.

 

[slcdawg]

Thinking I will mill the grain twice and then mash for an extra 30 min to compensate for any loss in eff.

 

[MaxStout]

Or recalculate for a 4 gallon batch and not worry about fitting it all in your kettle with a thinner mash thickness. Personally, I'd rather end up with 4 gallons at target gravity than 5 gallons that fell short.

If you really want to do the 5 gallon batch, you can always add some DME if your O.G. turns out low.

 

[Epimetheus]

If you really want to do the 5 gallon batch, you can always add some DME if your O.G. turns out low.

Yeah, DME was my first thought to help him out. I'm currently working on a similar project, the 15 lb grain bill is right at the capacity of my 8gal kettle. If I was to go any higher, I'd just "cheat" and use DME.

The suggestion of splitting the mash is a good idea.

On another thread Yooper suggested mashing a larger BIAB grail bill in a big picnic cooler if you have it - just drape the voile cloth into the cooler. It's still in a bag.

 

[Rdom]

I've tried doing a thicker mash just for kicks and did end up with a loss in efficiency - ~65% vs my usual 72-73% - on a 2.5gal batch. Like the others said, I would brew a smaller batch so you can mash with your entire volume.

 

[slcdawg]

Thanks for the suggestions. I may scale it down. I agree, better to scale it down than not hit my OG. I'm planning on aging for 6-9 months so want to get it right.

I do have access to a cooler, so could try that as well.

 

[ArcLight]

1. try mashing cooler for longer, and make sure you have a tight crush

2. really squeeze the bag and then soak the bag in another pot to get the trapped sugars out of the grain.. You may have too much liquid so you will have to boil longer and add these runnings in after some water is boiled off if there is no space

3. use Fermcap to prevent boilovers

 

[bannerj]

I did 18lbs in an 8 gal pot and made a huge mess. Then I did a partial mash for the next beer that big. Then I bought a bigger pot.

 

[bannerj]

This is a great thread:https://www.homebrewtalk.com/f36/thick-mash-vs-thin-mash-56439/

 

[slcdawg]

Good info - thanks for the link.

FYI - I borrowed a 10gal cooler and mashed 19.4 lbs of grain at a thickness of 1.7 qt/lb in my bag. For some reason only ended up with 58% efficiency following my mostly standard procedure. I was able to do no sparge and get the right volume (6 gal pre-boil) but was disappointed in the efficiency. Have to think about that.

The good news is I was able to get a 2nd runnings batch - 6 gal 1.037 gravity from the remaining sugars.

 

[RM-MN]

Good info - thanks for the link.

FYI - I borrowed a 10gal cooler and mashed 19.4 lbs of grain at a thickness of 1.7 qt/lb in my bag. For some reason only ended up with 58% efficiency following my mostly standard procedure. I was able to do no sparge and get the right volume (6 gal pre-boil) but was disappointed in the efficiency. Have to think about that.

The good news is I was able to get a 2nd runnings batch - 6 gal 1.037 gravity from the remaining sugars.

Did you do anything special about the crush? I have a Corona style mill and mill my grains very fine, as fine as I can with that mill. The bits of grain look like corn meal and flour, the husks are ripped to shreds. That will get me about 80% efficeincy with no sparge if I squeeze all the wort I can out of the bag. If I didn't squeeze, the efficiency would be much less and a second "small beer" could come from sparging the grains then.

 

[pdxal]

Adding those second runnings from sparging in another pot and boiling down is how you can compensate for any loss in efficiency. Not traditional BIAB, but it works.

 

[slcdawg]

Did you do anything special about the crush?

This may be part of it. I milled the grain at a new LHBS - i.e. different mill than normal. I was going to double-mill but they talked me out of it. I have double-milled in the past with great success (~78% Eff)...but most of the time I do a standard mill and still get 72%

 

[ShadyBrewer]

I've done it. Just sparge after the mash. You're basically using the bag as a false bottom and pot as a mash tun.


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[ShadyBrewer]

Double post

 

[slcdawg]

I've done it. Just sparge after the mash. You're basically using the bag as a false bottom and pot as a mash tun.

Curious - what type of eff did you get with low thickness?

 

[ShadyBrewer]

I've gotten between 75-85 doing it this way. I used to use a 5 gal pot so I had to cut back on water in the mash so I would just sparge afterwards. I still sparge to some extent. I feel better rinsing the grains of all the sugary goodness


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[monkeyman1000]

I'm am still pretty new (bottling batch 13 this weekend) and I have only done one bigger beer with an OG of 1.090 predicted and 1.086 actual. FG was 1.020. My ratio was 2.2 qts/lb which is thicker than my usual 3.0 to 3.5 qt/lb ratio. My efficiency into kettle is usually around (mash efficiency-preboil) 80s but with the bigger beer it went down to 73% ( 73% efficiency into kettle, 70.9% end of boil efficiency and 66.4% efficiency into fermentor). Take this with a grain of salt though as I am still new to the record keeping and to brewing but I did notice a drop with the thicker mash. It tasted good though. It was the Ol' Yule Loggy from Brewing Classic Styles. Oh, I use a 4 gallon pot and ended up with about 1.5 gallons of beer into packaging.