Does this online batch sparge calculator completely suck or am I retarded?

Onebeer.net :: Homebrew :: Batch Sparge Calculator

I used this today and wound up way short of my calculated runoff goal.


Here are the values I inputted:

Total grain: 11.5 (lbs)
Total wort pre-boil: 6.5 (gal)
Mash water ratio: 1.25 (qt per lb)
Grain absorption: .125 (.125 gal per lb is generally accepted)
Mash/Lauter deadspace: .5 (gal)

Now, I kept .125 as the default. I am assuming that this is the thing that screwed it up. I don't know the absorption (yes, I know.. buy BeerSmith), so I just went with what they said.

I mashed with just over 3.5 gal, as suggested by AHS and the calculator. 60 minutes at 150 F. Anyway, after draining the first runoff, I got 2.25 gal, not 3.25 as the calculator indicated. I am certain that I do not have a stuck sparge.

It also indicates to add 3.25 gal for the second runoff.

So, I am currently heating 4.25 instead of 3.25 since the first runoff was a gallon short. Is this the right thing to do?

So WTF happened here? Was the grain absorption just that much higher than their estimation or did I do something wrong?

Grains used:

10.5 lb Belgian Pilsner
.5 lb Vienna Malt
.5 lb Cara Vienne

The grain absorbed 1.25 gallons of water or about .11 per pound.
2.25 gal first running sounds about right.
The math for grain absorbtion is off.
And it didn't allow for the dead space, either.

I used this one before I bought BeerSmith:
The Brewer's Recipe Calculator

Yea...i guess it must be off if your batch is short. keep it simple. Keep on sparging until you have your pre-boil volume in gallons.

Thanks for the quick responses. That is sort of what I figured. I just wanted to make sure.

Once more question, though. Is it safe to assume that the grain is not going to absorb any additional water during the sparge? i.e. is it completely saturated after the first runoff? Or should I allow for an extra quart or something?

The grain should be saturated by then.

Thanks, you all were right. I ended up with almost exactly 6.5 gal, which should give me about 5.25 gal post boil, based on prior brewing.

I got 14 brix or 1.057 SG preboil via my refractometer, which should yield about 1.070 SG post boil. Reasonably close the the AHS target OG of 1.068. If I hit 5.25 gal, that should be 87% efficiency.

Until you get your equipment nailed down, it's always a good idea to heat up an extra gallon or so of sparge water for cases like this.

did you take into account any dead space in the tun ?Mine is a about a qt so I adjust for that also.

The easiest way to get a handle on water volumes when you start batch sparging is to do it empirically. Mash with whatever ratio you like. Then measure the amount of runoff you get from your mash. Subtract that from the total volume you want to boil. The answer you get is how much sparge water to use. After you do it that way a couple times, you'll have a handle on your grain absorption and tun losses and you can calculate it in the future.