Author Topic: Water added after cooling does not adjust OG computation  (Read 3094 times)

Offline ringmaster

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Water added after cooling does not adjust OG computation
« on: July 25, 2011, 02:59:40 PM »
I recently brewed a recipe using a printout of a brewsheet that was dead-on, up until the Cool and Prepare Fermentation phase:



If the estimated post boil volume is only 2.6 gallons with a 1.060 SG, then I add water to achieve a fermentation volume of 5.0 gallons, the SG will, by necessity, drop precipitously.

Why does Beersmith show the same SG for both before and after adding water to the fermenter?  This seems like a significant bug, since the calculations based on the batch size (measured into the fermenter) would need to be based on information entered about malt.

Offline MaltLicker

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Re: Water added after cooling does not adjust OG computation
« Reply #1 on: July 25, 2011, 07:30:50 PM »
I believe it is because both of these 1.060 are estimates of the final OG.  The SG of the 2.6 gallons post-boil should be more like 1.118 or so, right? 


In the BrewProcess TXT report, there is an Estimate of the Pre_Boil Gravity, but I'm unsure if it will show you the gravity of the 2.6 gallons.  Select this View of the Recipe and see what it does. 

Est Pre_Boil Gravity: 1.043 SG   Est OG: 1.052 SG

(These numbers are from a full boil brew.) 

Offline BeerSmith

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Re: Water added after cooling does not adjust OG computation
« Reply #2 on: July 26, 2011, 04:32:58 PM »
Hi,
  The OG is based on the overall brewhouse efficiency and volume into the fermenter.

  It is NOT calculated forward from the losses or dilutions. 

  This is due to the definition of what brewhouse efficiency actually is (it includes losses):

 http://www.beersmith.com/blog/2008/10/26/brewhouse-efficiency-for-all-grain-beer-brewing/

Cheers,
Brad
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