Decoction mash with batch sparge - volume additions query

Hi,

I want to make a Weizenbok and wanted to try using a single decoction mash followed by a batch sparge. I've been using Beersmith for all my single infusion / batch sparge recipes so far and have found it to be spot on with vols and temps, SG readings.

I was a bit unsure for the amount of batch sparge water BS says to add when doing a single decoction mash for 18 lbs of grain with a batch size of 6 Gallons.

The settings/figures in the mash profile are currently:

Protein rest: add 9.41 US Gallons of water at 127F; step temp 122F; step time 35mins

Saccharification: decoct 3.86 US Gals mash and boil it; step temp 154F; step time 45 mins

Batch sparge with 1.42 US gals of 168F water
(this doesnt seem like a lot of water (proportionwise)..... when I do infusion mashing, I would normally add 5.92 gals water (mash in); then add approx 2.38 gals batch sparge 1st step;steep; drain the lot into the boiler; add another approx 2.38 gals sparge water 2nd step);steep; drain into boiler.)

Am I right in thinking that I dont have to do a mash-out as I'm batch sparging with lage vols of liquor?

Anyone out there throw some light on this please?

Cheers,

Rob

That seems to be about 1.3 quarts of water per pound of grain, so that seems about right for the mash.

The thing with a big grainbill, you tend to lose some efficiency because of having less sparge water to get to your boil volume, but in my case my efficiency is always better when doing decoctions so it evens out when figuring out the probable OG.

I never do a mash out when I batch sparge- there really isn't any reason to as the first round of batch sparging can be a bit hotter and works as a mash out.