How do I calculate Water Needed for Sparge?

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RonRock

RonRock

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I'm getting ready to brew up Ed's Hefeweizen. His recipe is 5.5 Gal. I am trying to learn how to use ProMash. When I put in the amount of grains 11 Lbs. and 1.25 Quarts Water to Grain. I get a 3.44 Mash Gallons.

I'm sure the software is correct. What am I doing wrong. Should'nt I end with 5.5 gal? I will also need to figure for boil off.


I Batch Sparge. And will want 7 gallons in my pot to start. I figure if I boil off too much I can add to the Boil. That would be better than having to boil too long to get the volume down to 5.5. Correct?
 
edit: I've been beaten by a calculator; just use that!

You will probably want to end up with around 7 gallons of wort pre-boil. So what I do is drain the first runnings and measure that. Then I see what I lack to get up to 7 gallons and divide that by 2 (double batch sparge).

So if I get 2 gallons of first runnings (after water absorption) then I will need 5 gallons of sparge water... Divided by 2 is 2.5 gallons for the first sparge and the second sparge.

This will depend on your boil-off amount.
 
Your sparge water calculation is based on the volume of your first runnings compared to your intended preboil volume.

3.44 gallons is your mash(strike) water, not your sparge. However, due to grain absorption during the mash, you will not collect 3.44 gallons from the first runnings. I typically see .10 gallons/lb of absorption. Using an 11 lb grain bill, you'll lose 1.1 gallons to absorption, draining 2.34 gallons to the brew kettle. Assume 15%/hour boiloff if you haven't calibrated to your system and adjust from there.

For me, I aim for 8 gallons preboil, 6 at the end of the boil, 5.5 into the fermenter for 5 gallons of final product.
 
flyangler18 said:
Your sparge water calculation is based on the volume of your first runnings compared to your intended preboil volume.

3.44 gallons is your mash(strike) water, not your sparge. However, due to grain absorption during the mash, you will not collect 3.44 gallons from the first runnings. I typically see .10 gallons/lb of absorption. Using an 11 lb grain bill, you'll lose 1.1 gallons to absorption, draining 2.34 gallons to the brew kettle. Assume 15%/hour boiloff if you haven't calibrated to your system and adjust from there.

For me, I aim for 8 gallons preboil, 6 at the end of the boil, 5.5 into the fermenter for 5 gallons of final product.
Click to expand...



Thanks All.

Actually 8 gallons preboil should be better for me also. After I came up short last time I spent the day boiling water. That day I was boiling off 2 1/4 to 2 1/2 gallons per hour. That seemed like a lot of boiloff. So I was going to play it safe. But after reading your post Flyangler, maybe I should go for 8 gal.

Now I'll study up on the replies.
 
DubbelDach said:
Yeah, I was sure there'd be a lot of math in this thread, and formulas, and science....

But I'm math-retarded and just cut to the chase! :tank:
Click to expand...

I'm a numpty when it comes to math under most circumstances; but, I like to have at least a basic understanding of how the calculations are derived. This stuff is just simple arithmetic. :D

Jason
 
I think I have this out. Please tell me if I got it.

Start with 3.44 gallon in MLT 90 min.

Drain. Measure amount. Should be about 2.34 gal.

I want 8 gallon in pot pre boil. So 8 minus 2.34 = 5.66 gal.

So 5.66 Divided by 2 = 2.83

I do 2.83gal for about 15 min

then another 2.83 for 15 min

Leaving 8 gal in pot.
 
Thats what I do... so if its wrong; we are wrong together!
 
RonRock said:
I think I have this out. Please tell me if I got it.

Start with 3.44 gallon in MLT 90 min.

Drain. Measure amount. Should be about 2.34 gal.

I want 8 gallon in pot pre boil. So 8 minus 2.34 = 5.66 gal.

So 5.66 Divided by 2 = 2.83

I do 2.83gal for about 15 min

then another 2.83 for 15 min

Leaving 8 gal in pot.
Click to expand...

Spot on, but just for simplicity's sake, you might want to round to more workable numbers (2.8 gallons) and just compensate a smidge with your strike water. I know I can't measure 2.83 gallons accurately!
 
And you also don't really need to let the other sparges sit for 15 minutes. 5 or so would be fine.
And what temps are you striking and sparging with?
 
RonRock said:
I'm getting ready to brew up Ed's Hefeweizen. His recipe is 5.5 Gal. I am trying to learn how to use ProMash. When I put in the amount of grains 11 Lbs. and 1.25 Quarts Water to Grain. I get a 3.44 Mash Gallons.

I'm sure the software is correct. What am I doing wrong. Should'nt I end with 5.5 gal? I will also need to figure for boil off.


I Batch Sparge. And will want 7 gallons in my pot to start. I figure if I boil off too much I can add to the Boil. That would be better than having to boil too long to get the volume down to 5.5. Correct?
Click to expand...

Use the Pragmatic Empirical method. Mash with whatever ratio you like. After your mash runoff, measure how much wort you have. Subtract that from the preboil volume you want. The answer you get is the amount of sparge water to use. Simple and direct.
 
Thanks for the help everyone. I got through it. Missed my mash temp. But learned a lot with this round.

OG 1.050 a little low Target OG 1.052. I'll live with it and drink it when it's ready.
 

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