What is Batch Size in recipe view (Beginning or ending volume of beer)?

[SkyFlyer]

Hello.
Hope the brewing is going good for you all!
I am still struggling with a few settings in Beersmith, in particular Batch Size.
I have kind of asked about this before, but with too many other questions in the same post, sometimes it is hard to find the answer.
So, one question this time!
I am having some issues with carbonation and I believe that my sugar amounts are not correct.
The bottles are not exploding, just too much foam when pouring.
And yes, I am cleaning and sanitizing enough, probably over the top.
My question has to do with Batch Size in the recipe view. 
I want to end up with 10 gals of beer to bottle. 
I have my equipment set up to allow for around 0.75 gal of trub loss and 0.5 of tun loss.
I want to allow for the primary in 6.5 gal carboys and secondary in 5 gals carboys.
Also, I lose a little volume each time I rack the beer.
So, I usually start with a 11.5 gal batch size.  This way, I usually end up with close to 10 gal. of beer to bottle.
The volume amounts seem to be working pretty good for me.
The problem I have is this. 
The amount of sugar to be added is different if I use a Batch Size of 10 gal vs. 11.5 gal.
If I start with 10 gal Batch Size, I end up with less than 10 gals of beer to bottle (which I have not tried yet)
If I start with the 11.5 gal Batch, I end up with 10 gals of beer, but then I seem to end up with excess carbonation (in some batches, not all).
So, what is your experience? 
Is Batch Size really what you start with or what you want to end with in beer volume?
I'm thinking that I might just use the Carbonation tool to figure out the sugar based on the volume of beer that I am actually going to bottle and not rely on the recipe amount.
Any thoughts?
Thanks
Bob

 

[SkyFlyer]

Anyone have any thoughts on how Beersmith works here?
Is Batch size what you start with, or what you end up with when you are ready to bottle.
Or am I just making this out to be more of big deal than it is?!

Thanks ...Bob

 

[MaltLicker]

Batch is the final volume of wort you have at end of boil.  Includes leave-behinds in boiler and on floor. 

If you were to only count the liquid you "selected" for the fermenter, then your EE% would suffer.  You made more wort, and should take credit for it. 

Conversely, brewers habitually coming up short in OG may not be counting some volume losses along the way.  BSmith or any program is only as good as the inputs. 

 

[dharalson]

Sky

You asked a couple of different questions in the same post, again 

The Batch size is the amount of liquid in the end of the boil.
To elaborate:
The grain bill has an assumed amount of potential sugar determined by grain type and weight.  The details of the potential sugar for each grain type is found in the Grain detail window;  Double Click on any grain to pull up this window.  Look for the Potential in the middle of the window.  The number is typically about 1.035.  The simplest way to understand this is to think in terms of points per gallon.  1.035 means one pound of grain has the potential sugar to reach a SG of 1.035 in one gallon of wort.  This is 35 points of sugar.  Therefore 10 pounds of grain at 1.035 will contain a total potential sugar of 35 x 10 - 350 points.  This potential sugar is reduced by two efficiency factors, conversion efficiency and sparge efficiency; these combine to the Brewhouse Efficiency.  Using the typical number of 75% and the example above your would have 350 x 0.75 = 262 points of sugar at the end of the mash / sparge.  Assuming a 5 gallon batch size that would be a starting SG of 262 / 5  =  52 points/gallon or 1.052.

Now, your question actually is about bottle carbonation and priming sugars.
After the fermentation, all of the fermentable malt sugars should have been consumed by the yeast.  This can be checked by a SG read at bottling.  This number should be in the 1.010 to 1.016 range depending on the style, yeast, mashing techniques.  Beersmith will estimate the Final SG based on your inputs.  If you are within a couple of points of this number you are ok.
The carbonation is then based on the amount of sugar you add at bottling.  This will depend on the volume at bottling.  My guess is that Beersmith will be using the input Batch size for this calculation.  There will be a small volume loss due to settlement during fermentation but this should be a relatively small error.  At the bottom of the Recipe View window is the Carbonation calculations. 

You input the Carbonation level based on the style, typically about 2.5.  You also need to input the temperature.  For bottle carbonation, use storage temperature during the bottle fermentation stage, usually 60-70 degrees.  The temperature number can make a significant difference.  Measure carefully and record the actual amount of sugar used.  If you consistently over carbonating, reduce the sugar used.  You can make a consistent across the board change by adjusting your Beer Temp.

Hope this helps, David