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-   -   Another batch sparge question. Trouble with a big beer. (http://www.homebrewtalk.com/f36/another-batch-sparge-question-trouble-big-beer-376811/)

lakedawgs 12-28-2012 01:53 PM

Another batch sparge question. Trouble with a big beer.
I have been using the BIAB method for a couple of years with good success but am moving to a cooler for mashing and batch sparging to improve my efficiency.
I have read a ton but cannot wrap my mind around the strike and sparge water volumes for a big beer.

We are using a 70qt converted Igloo Xtreme cooler.
8 Gallon batch, Russian Imperial Stout
33# of grain

At 1.25qts per pound that would be 41.25qts/10.3gals of strike water. With a 10% absorpsion rate, that would be 9.25gals from the first runnings. This only leaves about gallon to a gallon and a half for sparge water volume. I know I could sparge with a bit more water and increase my boil time and vigor to get a bit more boil off, but it seems so little water would yield almost nothing.

I have also read that Denny suggests trying to get about 1/2 the preboil water from the first runnings and 1/2 from the sparge/2nd runnings. At that rate I would less than .65qts of water per pound for my strike water.

I feel like I am likely missing something basic here. Any thoughts would be appreciated.

Xpertskir 12-28-2012 01:58 PM

Mash thicker and increase your boil time. You could also increase your grain bill and do the RIS from your first runnings and a partigyle with the remaining sugar.

lakedawgs 12-28-2012 02:16 PM

I thought about doing a partigyle but this 8 gallon batch is the first of 3 I am doing for my share of a bourbon barrel addition. Unless I hear different I think I am going to strike with about 8 gallons (just under 1qt per gallon), and sparge with about 3.5 gallons.

cluckk 12-28-2012 02:24 PM

The 1.25 to 1.5 qt/lb is fine for a regular brew, but with really big, high gravity brews you want to lower it to 1 qt/lb. I've found when I forget to make this change my efficiency goes through the floor.

lakedawgs 12-28-2012 02:38 PM

So you lower the qts/per pound formula a bit for big beers, that is really interesting. Is that simply so you can have a bit more sparge water or something else?

GotPushrods 12-28-2012 03:15 PM

Firstly, the static 10% absorption might work with a specific mash thickness sometimes, but will be way off in many cases. I use 0.11 gallons/lb grain and it works very well. This would give you (0.11)*(33) = 3.63 gallons stuck in the grain. Sounds like a lot, but grain is a wort sponge.

Here is what I would do... just a suggestion.

I'd start with 9 gallons strike water to keep the numbers easy. That's 1.09 qt/lb.

You'd get approx. 5.25 gallons first runnings (9 - (0.11*33)) minus your dead space. Assuming a 2 hour boil (I do with a beer this big) you'll need 10.5 gallons pre-boil assuming ~1.25 gal/hr boiloff. Adjust for your system.

Sparge with 5.25 gallons RO water, since you'll get out exactly what you put into the sparge... the absorption is already accounted for.

lakedawgs 12-28-2012 03:25 PM

I like that idea so far. I was thinking 10% absorption not .1 gal/pound of grain, thanks for the clarification, big difference.

GotPushrods 12-28-2012 03:34 PM


Originally Posted by lakedawgs (Post 4722347)
I like that idea so far. I was thinking 10% absorption not .1 gal/pound of grain, thanks for the clarification, big difference.

You betcha. Like any formula, it's garbage in, garbage out... only as good as the inputs you give it. Once you get your system losses, absorptions, and volumes dialed in, you can estimate the whole process very well.

lakedawgs 12-28-2012 03:37 PM

Really looking forward to start mashing and sparging in a cooler but my first 3 brews will be monster stouts so I want to have my #s and thoughts in the right direction from the start.

Bobby_M 12-28-2012 06:36 PM

When you break the 1.100 OG barrier, it's just better to do a no sparge mash for the big beer and force yourself to partigyle for a second beer.

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