Too much calculated sparge water volume - how to correct?

[JJFlash]

My Beer Smith calculated sparge water volume is always way too high. 
Just brewed an Imperial Stout - 10 gallon final batch volume with about 2 gallons too much sparge water. 
Can I tweek something to get more accurate sparge volume?

46 pounds grain at 1.25 quarts/pound = 14.45 gallons.
BS calculated sparge volume = 6.72 gallons.
Total water volume was then 21.17 gallons.
I needed to collect 15.22 gallons, so easily had about 2 gallons excess wort not going in the kettle.

Thanks,
JJ

[philm63]

There are lots of reasons you may be coming up with too much sparge water in the calculations, and without knowing your equipment profile, it is difficult to pin down. The software calculates water volumes based on your profile settings and dialing it in sometimes takes a while (and several batches).

The quick and dirty answer is this; close the valve when you've hit your target volume in the kettle.

If you'd like to post your equipment profile here, we could help you identify any issues.

[durrettd]

Check this link for info on setting up and fine-tuning your profile.

http://www.beersmith.com/forum/index.php/topic,5140.0.html

[JJFlash]

Here is my equipment profile with a Blichmann 20 gallon mash tun.

Batch Size: 11.00 gal
Mash Tun Volume: 20.00 gal
Boil Volume: 15.22 gal
Mash Tun Weight: 26 lbs
Evaporation Rate: 9.9 %
Mash Tun Specific Heat: 0.12 cal/g-deg C
Boil Time: 120
Mash Tun Deadspace: 0.40 gal
Top-up for Boiler: 0.00 gal
Equip Hop Utilization: 100.00 %
Losses to Trub/Chiller: 0.75 gal Cooling Loss (%): 4.00
Top up water for Fermenter: 0.00 gal

This issue is not dealt with in any of these self help discussions.  Before Beer Smith I used ProMash and it would correctly calculate the sparge volume to within one quart.  Even before ProMash was invented I would calculate the correct sparge volume.  I opened the mash tun valve and when the tun ran dry I had the correct volume in the kettle.

[m750]

This is interesting to me, do you happen to have a copy of your recipe shared on beersmithrecipes that I can look at w/ settings?
Have you tried measuring your grain absorption ratio? I wonder if a slight inaccuracy in this number x44lbs is something that is causing your issue.  Mine is set at .96.

[JJFlash]

This is interesting to me, do you happen to have a copy of your recipe shared on beersmithrecipes that I can look at w/ settings?
Have you tried measuring your grain absorption ratio? I wonder if a slight inaccuracy in this number x44lbs is something that is causing your issue.  Mine is set at .96.

The default grain absorption in BeerSmith is 0.96 fluid ounces / ounces, so that's about 0.12 gallon / pound. 
Depending on the system normally runs 0.10 - 0.20 gallon / pound.
Looks like 0.08 gallons / pound may be closer estimate with my Blichmann mash tun.

 

[m750]

I'd still be interested in seeing the full recipe. I've spent more than my fair share of time tweaking beersmith to get my numbers closer to accurate, and I'm wondering if their could be something else that's throwing it off.
Do you use a really course crush?
AO

[MikeinRH]

This is actually a very good topic and I've found myself in situations where I've had both too much sparge water, and not enough. I find it better to have too much sparge water on hand when the kettle volume appears insufficient ... and when evaporation is expected during the boil. You can always turn off the valve when your runnings reach the desired level. I've also used the excess and available sparge water to add volume to a shorted fermenter. This obviously affects the original gravity, but it definitely saves time. If time is not an issue, and the kettle is short, I prefer to add remaining sparge water to the bed of grain and let it sit for another 30 minutes before adding to the kettle. I used to freak out over these issues when I was a beginning brewer. The reality is that there's very little you can do to mess up a batch during the pre-boil stage. The biggest disappointment is when you spend more than half a day brewing, and you don't end up with an optimum volume for the fermenter.

[JJFlash]

So this was a big imperial stout OG 1.120 - going into the whiskey barrel in a few weeks.
I am pained to watch 2 gallons of high gravity - excess sparge get tossed down the drain because of a bad calculation.
My goal with BeerSmith is to duplicate my previous technique of last drop of the mash tun hits the initial boil volume perfectly.
No losses at all. Been doing this for years. Not hitting it with BeerSmith, tho I do believe the grain absorption tweek may soon fix this.
It seems to be the only variable we can adjust, and the rest of my calculations are spot on.
Switched to 20 gallon Blichmann kettles at the same time as switched to BeerSmith - violated my own rule of one change at a time -dumb move again!

recipe for 10 gallons:
35 lb pale malt
6 lb munich II
1.5 lb crystal 60
1.5 lb chocolate
12 oz crystal 120
12 oz de-bittered black malt
12 oz roasted barley
2 lb dark sugar

[m750]

JJ -
the reason I keep asking for the beersmith recipe, is that it contains much more than the grain bill, it contains all sorts of equiptment settings, mash settings, etc, that might be overlooked.
Hopefully that setting works out, if not, I encourage you to post either an exported copy of the recipe, or share a copy via beersmith recipes, so some other eyes can get the whole picture.
HTH,
AO

[brewfun]

So this was a big imperial stout OG 1.120 - going into the whiskey barrel in a few weeks.
I am pained to watch 2 gallons of high gravity - excess sparge get tossed down the drain because of a bad calculation.

What's missing from this discussion is whether you hit your gravity and volume. If you did, then the additional water is moot.

Before you figured out the grain absorption (which I believe to be the correct answer), I ran a model based on your initial information and only yielded a nominal 1.100. An 11 gallon yield of 1.120 requires about 80% mash efficiency, which is excellent for a batch this big.

I don't know what "high gravity" may mean, but even if it's 1.040, that two gallons only adds 1.007 to the initial gravity at 11.75 gallons (post boil kettle volume). I'm all about high efficiency and accuracy, but I wouldn't do any hand wringing for a 0.6% loss of sugar. I probably would have just added it halfway through the boil and enjoyed the additional pints, later.