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Two mashes, one boil?

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HeadyG

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I've got a few stouts under my belt and I want to take a run at a big imperial stout. The recipe I want to use calls for almost 23 pounds of grain and a three-hour boil to make a 5-gallon batch. I plugged everything in to BeerSmith and it says I will need nearly 12 gallons of water for the mash, resulting in an 8.95 gallon pre-boil volume. The issue is I only have a 10-gallon kettle, a couple 10-gallon stainless steel stockpots and a 7.5 gallon Anvil bucket fermenter. So obviously I cannot do the mash in one shot.

My question is: Is there any problem with simply splitting the grain and water in half to do two BIAB mashes with nearly 6 gallons of water each? I would pour the wort from the second mash into the kettle with the first mash and do my boil like normal. It seems logical that this should work, but I'm wondering if there's anything I'm not thinking of that could ruin my day. Any insights are appreciated.
 
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HeadyG

HeadyG

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I can't see a reason why this 50/50 approach won't work. But it does beg the question, why a three hour boil? Because that's the main reason for having so much water to begin with.
Thanks for the reply. My understanding is it's a combination of reaching the desired OG, mouthfeel/achieving the desired viscosity and caramelization of the sugars.
 

Transamguy77

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I would just go with a thicker mash and then sparge, I know most BIAB brewers don’t sparge, I used too so I know at times it can be a PIA but it’s way easier than doing 2 mashes.

I would start with like 6 gallons and then add my grains and top off the kettle Right to the top and then mash for however long and then see what your volume is and sparge with the difference. So if your volume is 4 gallons and you need 7 then sparge with 3 gallons. You can heat up water in another pot while mashing so there won’t really be any wasted time.
 

RM-MN

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You can heat up water in another pot while mashing so there won’t really be any wasted time.
You can use cool water for sparge with the same results and the only wasted time will be the increased time to boil...which seems to be pretty minimal as the hot, wet grains warm up the cool water pretty well.
 

Noob_Brewer

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I have the 10.5gallon foundry and brewed a RIS about two weeks ago. There are a couple ways you could do this but I ultimately decided to go with one mash and a big sparge. If one of your other vessels has a spigot, this strategy as it was quite easy for me and a very enjoyable brew day.

 

jerrylotto

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I just did this and tried an iterative mash. Instead of two strikes and two sparges, I mashed the first half, sparged, and then collected a strike volume of the resulting wort and used it to mash the second half. You may have to check pH and adjust it a little (the wort might be too acidic) and you have to have enough water on hand to sparge the second batch. Now my efficiency was a little lower using this method but still acceptable and the resulting wort was a full strike volume more concentrated eliminating the need to boil off an additional 3 gal of water.
 
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HeadyG

HeadyG

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HeadyG

HeadyG

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I just did this and tried an iterative mash. Instead of two strikes and two sparges, I mashed the first half, sparged, and then collected a strike volume of the resulting wort and used it to mash the second half. You may have to check pH and adjust it a little (the wort might be too acidic) and you have to have enough water on hand to sparge the second batch. Now my efficiency was a little lower using this method but still acceptable and the resulting wort was a full strike volume more concentrated eliminating the need to boil off an additional 3 gal of water.
Interesting, thank you.
 

BrewnWKopperKat

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almost 23 pounds of grain and a three-hour boil to make a 5-gallon batch
You didn't mention OG/FG for this batch. I suspect it may be outside the range that a doube-mash can produce.

Your approach in #1 seems reasonable. From my experiences with double-mashes (and related reading), your approach also seems more predictable. With darker beers (of any OG), I'm of the opinion that a longer boils adds to the flavor. Time wise, I don't see a shorter brew day with a triple-mash.
 
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HeadyG

HeadyG

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You didn't mention OG/FG for this batch. I suspect it may be outside the range that a doube-mash can produce.

Your approach in #1 seems reasonable. From my experiences with double-mashes (and related reading), your approach also seems more predictable. With darker beers (of any OG), I'm of the opinion that a longer boils adds to the flavor. Time wise, I don't see a shorter brew day with a triple-mash.
You're right, I wasn't sure if it was relevant to the question. It's the recipe for Perennial's Fantastic Voyage from Craft Beer & Brewing, but I want to use different adjuncts. I'm looking for a 1.120 OG and an FG around 1.045. The pre-boil gravity should be approaching 1.090. If I don't hit the pre-boil gravity I plan to bump it up with DME. Thanks for the insight.
 
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