Batch Sparging Technique (10gal) -- Critique Needed

[Slip_Stick]

I have been successfully brewing 5 gallons with a single batch sparge, but now i'm moving up to a 10 gallon batch. I can't do a single batch sparge for this size because of the size of my MLT is only 48qt, so i must convert to a double batch sparge. I'm wondering if i'm on the right track.

Here is what i think i need to do for a 10 gallon batch with 17.25# malt.

1.) Add 5.4 gallons (1.25*17.25) @ 168 to achieve mash temp of 151
2.) After 60 min, check conversion.
3.) Recirculate wort and vourlof until clear.
4.) Collect 4 gallons of wort (minus 1.4 for grain absorption).
5.) Add 5.3 gallons @ 185, stir, let settle for 5-10 min.
6.) Repeat step 3, collect 5 gallons (.3 gal loss grain absorption).
7.) Repeat Step 5 to collect a total of 14 gallons (pre-boil volume)


So here's my questions:

1.) How much water loss to the grains should i account for during the sparge's (is .3 gal loss too much or too little)?

2.) I realize the second and third running's will have much lower gravity than the first; so if im shooting for a OG of lets say 1.05, should i look for my first runnings to be around 1.07-8? Second and Third would be lower than 1.05?

Any advice/critique is much appreciated!

 

[Ace_Club]

I can answer the first question. You should not account for any grain absorption during the sparges. Assume that the grain has fully absorbed all the liquid it can during the mash.

As for the gravity question, I only measure the gravity after I've fully sparged, so I can't help you there.

 

[ElDuderino]

I have never allowed for grain absorption after the initial sparge, as I assumed the grain had already absorbed all that it could and the dead space of my mash tun had already been filled.

I don't measure the gravity of all my runnings anymore, but I was for a while. On a 1.058 beer I did a while ago:
First runnings 6.5 Gal @ 1.072
Second 6 Gal @ 1.036
Third 2 Gal @ 1.033

1.044 Beer
First 2.5 Gal @ 1.062
Second 4 Gal @ 1.021

1.086 Belgian Ale
First 5 Gal @ 1.089
Second 6 Gal @ 1.040

I don't know if this helps, and it's not scientific as I was probably changing my method a little for each brew, but it gives you an idea of how the numbers turn out.

Good Luck!

 

[BrewThruYou]

1.) How much water loss to the grains should i account for during the sparge's (is .3 gal loss too much or too little)?

I would get a program like Beersmith or Beer Alchemy. It made everything a lot easier for me.

 

[Misplaced_Canuck]

AS a general rule of thumb, grain absorption is 0.1gal/lb of grain. No additional absorption after the first batch.

I add water back to the mash until there's about 1/2" to 1" above the grain bed. In a 12-gallon mash (say around 20 lbs of grain), I usually add 2.5 gallons per batch sparge.

M_C