fly sparge calculations

Hey guys - rather new to the BS2 software.  I've been using it for about 4 months to do about 7 batches of all grain or so.  My confusion is in the fly sparging volumes.  The last batch I brewed was a single infusion with mash out for light body.  The mash water (including mash out) was a total of 3.75 gallons, which was all perfect.  The sparge water, however, required 7.69 gallons, with only .89 being lost to grain absorbtion.  I collected the full 6.25 gallons needed for my setup, but still had about 4 gallons of extra sparge water.  What setting am I missing that creates superfluous amounts of sparge water (fly sparging).  At least this time I knew enough to stop collecting.  My last recipe, I kept sparging with all the water, and ended up with a 2.5% ABV brew.   

Checking the "adjust mash tun for deadspace" button boosts the sparge water even higher (9 gallons or so).  The mash volumes and temps are dead on, but I can't comprehend the high sparge volumes. 

I'd really not rather heat up an extra 4 gallons of water if I don't need them.  Any suggestions on where I'm going wrong?

You could post up the .bsmx recipe file? I can't imagine what is going on.

Sounds like the 'mash out' quantity and perhaps some equipment settings for losses? 

.bsmx file for Equipment Profile would help, as grathan noted.

I mash-out with 5 quarts, and BS2 has me sparging with slightly more than I mash with, but not four gallons more. 


Style: American IPA
Recipe: 14B Elbow Deep IPA TYPE: All Grain

EE%: 71.00 % Batch: 5.25 gal      Boil: 7.50 gal BT: 75 Mins

Total Grain Weight: 12 lbs 11.7 oz Total Hops: 8.10 oz oz.

Name              Description                            Step Temperat Step Time   
Mash In          Add 15.54 qt of water at 161.8 F        151.0 F      60 min       
Mash Out          Add 5.00 qt of water at 210.3 F        164.0 F      10 min       

Fly sparge with 4.11 gal water at 168.0 F

Posting your details as Grathan and Maltlicker said, would lead to a more accurate answer.

But, a rule of thumb that worked for me was total boil volume plus 0.7 quarts per pound. I never like to run my grain bed completely dry because flow slowed so much, So, that figure would get me to a dry HLT and water that would end up a couple of inches below the grain surface when I was finished.

In time, I learned to stop my sparge inflow at 1.014 and outflow at 1.008. Whatever water was left over was used for cleaning.