Brewer's Friend Efficiency?????

Discussion in 'Recipe Editor' started by William257, Aug 26, 2019.

  1. William257

    William257 New Member

    Mar 8, 2017
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    Hello I have my equipment profile for Brewer's Friend set-up for BIAB. Now which target should I set it to Fermenter or Kettle???
  2. Yooper

    Yooper Administrator
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    Nov 16, 2013
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    Happily retired
    Upper Michigan/Florida
    Efficiency is based on the batch size target:

    • When batch size target is set to Fermentor: efficiency stands for 'Brew House Efficiency', which captures your entire system. It factors in sugar losses all the way to the fermentor.

    • When batch size target is set to Kettle: efficiency stands for 'Ending Kettle Efficiency', which is how much of the sugars from the grain were converted and made it into the kettle at the end of the boil.

    From our documentation page:
    Est. Boil Size and Boil Time
    Boil size is how much wort you will be boiling at the very start of the boil. This value is used for IBU calculations. For All Grain brewing (or any recipe set to batch target 'kettle'), start by entering an estimate. After the grain bill is setup, check the Recipe Tools -> Quick Water Requirements section to see what the system calculated as the actual starting boil volume based on the recipe and the selected equipment profile.

    These settings impact the efficiency calculation. (See efficiency below for full description). Our way of calculating efficiency has changed, and this is noticed on the Recipe Builder page. You can choose your boil size, and the amount of wort at the end by choosing the volume going into the fermenter, or the volume at the end of the boil. Those choices do NOT impact your efficiency calculation, but are there to assist you in ensuring your volumes are correct for your brewing.

    To understand the efficiency calculation, an example is best.

    Let’s say your boil starts at 6 gallons. You have 120 points of fermentables (e.g. 5 pounds of 30 ppg at 80% efficiency). You boil down to 5 gallons. In this example, your system may lose 1 gallon to kettle dead space, hop absorption, losses to the way you transfer wort, wort left in the chiller, and so on. In this case, you up with 4 gallons in the fermenter.

    In the old method:

    You’d select the fermenter target, and enter 6 gallons as your boil size. Four gallons would be your batch size, since that is the volume going into the fermenter.

    The software assumed that the difference from the 6 gallons at the beginning reducing to 4 gallons as the batch size was all boil-off.

    As a result, the OG was calculated as: 1 + ( 120 / 4 ) * 0.001 = 1.030

    That is clearly wrong because it indicates that all fermentable sugar was condensed into 4 gallons of wort. The reality is that it was condensed into 5 gallons of wort, and some of that was simply thrown away. The loss of wort does not increase specific gravity of the remaining wort, of course. The loss would have the same SG as the wort going into the fermenter.

    So in our updated calculation, you would select the batch size of 4 gallons as the target into the fermenter, enter 6 gallons as pre-boil size, and 5 gallons as post-boil size.


    You can also let the system calculate from your equipment profile’s boil-off rate.


    Now the OG can be calculated correctly:

    1 + ( 120 / 5 ) * 0.001 = 1.024

    You will notice that it is a 20% difference. That seems small to some, but we wanted to give the most accurate OG predictions possible for our users, both homebrewers and professionals.

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    Trialben likes this.

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