Batch Sparge Calculation - BeerSmith

Hello,

I am a little confused by BeerSmith’s batch sparge calculation. My pre-boil volume is 7.5 gallons. I have 10.75 lbs of grain, mashing at 151 F.

All things accounted for (dead space: 0.5 gallons, grain absorption: 0.125 gallons/lb), I should add 1.3 gallons for the first batch, and 3.75 gallons for the second batch. However, BeerSmith is telling me to add 1.6 gallons and 4 gallons for the first and second batches, respectively. Both are increased by about a third of a gallon.

Can anyone clarify the situation for me?

 

Can you screen shot or List your equipment profile?

 

Did you check the mash in amount, BS defaults to 1.25qts/lb. if you are calculating at 1.5 then it could be where the sparge difference is coming from as BS assumes you need more.

 

HelloGunfighter04,

Thanks for the quick response. Please see my equipment setup, mash profile below.

 

If batch sparging you need to check the box that states: "Drain mashtun before sparging", that should correct things, I think.

Also, some of the numbers used are kind of screwy, with 14.9 qts to mash in that is 1.39qts/lb, is that what you typically mash in with?

 

It's WAAAAYYYY easier than that. Mash with whatever ratio you like. I usually go about 1.66 qt./lb. When the mash is done, drain your tun. Measure how much you get. Subtract it from your boil volume. The answer you get is how much sparge water to use.

 

I was going to say the same thing but when people use software they like to dial it in so the computer does the work

 

Denny, are you attempting to get equal 1st and second runnings when you mash in at 1.66qt/lb? I've read that it will give the best efficiency to do it this way but wasn't sure how much people worry about it.

 

Thanks, that is a much simpler way to think about it, and I will probably just stick to this on brew day.

However, I usually like to figure out why something works the way it does. In this case the software accounts for variables which are important in understanding your system.

For the mash, BeerSmith is using a ratio of 1.2 qts/lb and taking into account the dead space. This is easy to verify, since my dead space is 0.5 gallons or 2 qts, then we have 12.9 qts that resulted from the calculation for the water/grain ratio.

I am still confused about the batch sparge additions.

I've confirmed the absorption used by BeerSmith is 0.12 gallons/lb-grain. This means 1.29 gallons are absorbed.

If we need 3.75 gallons in the first addition:
3.75 (half pre-boil volume) - 3.73 (mash-in) - 1.29 (absorption) = 1.27 Gallons
However, BeerSmith is telling me to add 1.6 gallons.

For the second batch it's supposed to be very simple. Half of the pre-boil volume is 3.75 gallons. BeerSmith is telling me to add 4 gallons.

My conclusion is that I'm simply missing a variable. Can anybody help?

 

I don't see why you think the numbers are off. You have it set for:
7.52 boil volume + 1.29 grain absorption + 0.5 tun deadspace = 9.31 gal water.

Your mash is 14.9/4= 3.73 gal , so you are using:
3.73 + 1.57 first sparge + 4.01 second sparge = 9.31 gallons

If you have a problem with the sparge amounts being so different then check the box for "sparge with equal batch sizes".

 

Like Denny says. Once you know your systems dead space and account for absorbsion (.13 gal/lb is a good start), it's really pretty simple math. You can either adjust your mash thickness for equal runnings, or use a set thickness in your main mash and lauter the rest when you sparge.

 

Getting close to equal runnings is the idea. I also get much better efficiency with a thinner mash than a thicker one. But equal runnings isn't a huge deal. If you're within a gal. of so there will be so little impact ion efficiency that you'll probably never notice.

 

You really don't need a computer program.
For two equal runnings it's as simple as:

Boil Volume / 2 = Sparge Water
Dough In Volume = Sparge Water + System and Absorbsion Loss

 

Thank you to everybody for your input!