Target:Fermentor calculates different pre-boil gravity

Discussion in 'Recipe Editor' started by Brewer #34185, Mar 23, 2016.

  1. Brewer #34185

    Brewer #34185 New Member

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    I have configured my equipment profile so that my kettle has 1 gallon of dead space. When setting the Batch Size Target to "Fermentor", the pre-boil gravity calculation appears to be taking that 1 gallon dead space as part of water lost due to boil-off. This results in an artificially low "boil gravity" as displayed in the recipe. It appeaers that the program thinks that there will be that additional 1 gallon boiled off, when in fact that one gallon is simply left behind in the kettle on transfer to the fermentor.

    To correct the issue, I switched the Batch Size Target to "Kettle", and added 1 gallon to the Batch Size to account for kettle dead space and adjusted the efficiency from brew house to kettle to get the same OG. After doing this, the boil gravity and OG line up properly (as verified by the Dilution and Boil Off Gravity Calculator).

    Here are my test recipes demonstrating the issue:

    http://www.brewersfriend.com/homebrew/r ... get-kettle
    http://www.brewersfriend.com/homebrew/r ... -fermentor

    Note that due to different pre-boil gravities, this also affects the IBU and color calculations. Unless I am misunderstanding how Target:Fermentor is supposed to work, I think this a bug.
     

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