first batch sparge tomorrow please help

Hello,
I have been doing fly-sparge AG brewing a while now and tomorrow I am giving batch sparging a go. This is in the hope of saving time. Currently a brew day for me and my buddy is a good 8 hours plus doing back-to-back ten gallon batches (overlapping some operations to decrease the total amount of time). My hope is to knock this down to around 5 hours. We plan on doing one humongous mash with a full 56 lbs of grain and batch sparging into two keggles.
I think I have the water amounts down properly, but am hoping one of you big-brain batch sparging gurus will double check me on it. Here is the spreadsheet:

23.00 Vb = total volume to be sparged to boiler (gal)
0.13 Ra = absorption rate of the grain (gal/lbs) (note: 0.13 is a good approximation)
0.31 Mt = mash thickness during conversion (gal/lbs)
56.00 Wn = weight of grain of the standard recipe (lbs)
20.00 Vr: Recipe Volume (gal)
76.00 Gr: recipe Gravity (gravity points, i.e. 1.046 = 46)


0.30 "R", the required mash thickness at runoff (gal/lb)
1.00 "S", the grain scale-up factor
56.00 "Wg", the total weight of grain needed for the batch-sparge version (lbs)
17.36 "Mv", Volume of mash water for conversion (gal)
-0.80 "Av", Addition volume of water needed to bring to first runoff volume (gal)
16.56 "Vm", the total volume of mash water that has been added to achieve "R" at the first runoff (gal)
11.50 "V1", the first runoff volume (gal)
80.94 "G1", the gravity of the first runoff
11.50 "Vs", the required volume of "sparge" water (if batch-sparge brewing)
40.37 "G2", the second runoff gravity (if batch-sparge brewing)
21.04 "Vt", the total mash-tun capacity required to hold all the grain and water (gal)

I get a little concerned because the amount of water to add to the mash for the first running is a negative number!? Is this normal?

That's way too complex.

Just go for a mash of 1.25qt per pound then batch sparge to volume or to 1010.

You can figure the math out if you want but the brewing is more important.

Sorry, I didn't follow the nomenclature.

But - If you're already comfortable fly sparging , then just mash as normal and then split the amount you would fly sparge with for two batch sparges.

For example, if you would normally fly sparge with 5 gallons, then the two batch sparges would be with 2.5 gallons each.

Thanks for the encouragment guys, but I read about the importance of having two equal run-offs. I see there is too much info on the spreadsheet (downloaded from a link on Dennybrew). The number I was interested in was the addition to the mash in order to get the total boil volume / 2 in the first running (which requires accounting for the grain absorption). However, when I plugged my numbers into the spreadsheet I got a negative number where I expected to see the amount to ADD.

Anyhoo, I have decided to say screw that spreadsheet. It looks like there is some mumbo-jumbo going on in it. Following the KISS method, I come up with the following:
Mash water required (56lbs * 1.25 qts per) = 17.5 gallons
Expected absorption (.13 gals per lb * 56 lbs) = 7.25 gal (approximately)
addition to mash to achieve desired first run-off = 1.25 gal [11.5 - (17.5-7.25)]

Does this seem reasonable?

I always start with how much I want to collect in total runnings. For me, that's usually about seven gallons. I then know that I want the total of my first and second runnings to each be 3.5 gallons.

Now, I always add sparge water to the mash before taking my first runnings. Since I know the total of my first runnings wants to be 3.5 gallons, I subtract from that the total amount of water I have in the mash, and add back in the amount that I'm expecting to lose to the grain. This is the amount I add, I don't know the techical term, to the mash after I'm done mashing. Stir well, let sit for ten minutes, vorlouf, and drain.

Then, add another 3.5 gallons of sparge water (no need to factor in the amount lost to the grain, the grain's already wet). Stir, wait, vorlouf, drain.

I think that's what you're doing. The reason you're coming up with a negative number, I suspect, is due to the huge amount of grain you are using.

the_bird said:

I always start with how much I want to collect in total runnings. For me, that's usually about seven gallons. I then know that I want the total of my first and second runnings to each be 3.5 gallons.

Now, I always add sparge water to the mash before taking my first runnings. Since I know the total of my first runnings wants to be 3.5 gallons, I subtract from that the total amount of water I have in the mash, and add back in the amount that I'm expecting to lose to the grain. This is the amount I add, I don't know the techical term, to the mash after I'm done mashing. Stir well, let sit for ten minutes, vorlouf, and drain.

Then, add another 3.5 gallons of sparge water (no need to factor in the amount lost to the grain, the grain's already wet). Stir, wait, vorlouf, drain.

I think that's what you're doing. The reason you're coming up with a negative number, I suspect, is due to the huge amount of grain you are using.

Click to expand...

I'm going to be doing my first AG soon, batch sparging in a 5 gallon round cooler... Now when you say you add sparge water to the mash before taking the first runnings, I assume this occurs after conversion? And when you add this sparge water, are you adding the 170 degree sparge water to the 150(+/-) mash?

Yeah. I mash with 1.25 wt/lb (approximately), hold for an hour for conversion, then add a bit more (calced the way I describe) before taking my first runnings. I usually add 170 degree water at that point, and for the sparge I'll add slightly hotter water (180 - 185), for a bit of a mashout (not critical for batch sparging) and since it helps efficiency).

Here is my method:

Take the total # of grain times 1.25 to 1.5. That is my initial addition at about 165 to 170 degrees (Brewsmith calculates the exact temp).

I assume .1 gal per pound of grain loss. and 1/2 quart lost in the bottom of my masher. (Coleman eXtreme with the relief at the drain)

First water addition for a 12# batch with 1.5 Qt/# would be:

12# X 1.5 Qt/# = 18 quarts = 4 1/2 gallons of water.

From the first runnings, I will get:

18 quarts - .1 Gal/# X 12# - .5 Qt = 12.7 quarts = 3.175 Gallons

I want to get 6.5 gallons into my boiling pot, so my sparge water is:

6.5 gallons - 3.175 gallons = 3.325 gallons.

So, I added about 8 gallons of total water, lost 1/8 gallon to dead space, and 1.2 gallons to grain loss. If your temp is low or high in the first mash, add the water that you need, and subtract it from the sparge.

Pretty basic, but I have never been off by more than a quart or two. I have hard time keeping my boil-off rate to within +/- 1/8 gallon per hour, so this is as close as I need to be. YMMV.

I'm building a spreadsheet to make this calculation a no brainer to get equal runnings and I think I've got it. Using your example, does this look about right?

This assumes mashing is done at 1.25 qts/lb and .1 gallons of water is absorbed by 1 pound of grain and the last bit (of which I'm not too concerned about) assumes .5 gallons evaporate during the boil.

Thanks!

Boy,look at all that science.I'm making 6 gal batches(batch sparge) and my grain bill varies from 10 to 14 lbs per.I've been using the same amount of water for all of em...9gals total for everything(mash,mash-out,sparge).I get 7.5 gals in my kettle every time.3.5 mash,2 mash-out(boiling),3.5 sparge.
For some reason(dumb luck)it works great with 75%effic.

Like most things i do,i keep it simple(KISS).
I love the idea of a giant batch though.
Cheers