Stand alone calculators for electric brewing

Discussion in 'Feature Requests' started by LarryBrewer, Aug 8, 2013.

  1. LarryBrewer

    LarryBrewer Active Member

    Joined:
    Jun 27, 2012
    Messages:
    1,728
    Likes Received:
    9
    Trophy Points:
    38
    Location:
    Portland, Oregon
    From a user who contacted us by email:

    Anybody have a source for equations on this?
     
  2. LarryBrewer

    LarryBrewer Active Member

    Joined:
    Jun 27, 2012
    Messages:
    1,728
    Likes Received:
    9
    Trophy Points:
    38
    Location:
    Portland, Oregon
    This link has some info:

    http://homebrew.stackexchange.com/quest ... ou/592#592

     
  3. Ozarks Mountain Brew

    Staff Member

    Joined:
    Nov 20, 2012
    Messages:
    7,485
    Likes Received:
    3,675
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    IT Managment
    Location:
    The Ozark Mountains of Missouri
    Besides the formula in perfect conditions, its also relative to the conditions, different pots, different insulation, different weather, pressure temps, elevation ?? Whether you're using pid pulse or on full power also??, with the lid on or off too :)
     
  4. LarryBrewer

    LarryBrewer Active Member

    Joined:
    Jun 27, 2012
    Messages:
    1,728
    Likes Received:
    9
    Trophy Points:
    38
    Location:
    Portland, Oregon
    Good points.
     
  5. Ozarks Mountain Brew

    Staff Member

    Joined:
    Nov 20, 2012
    Messages:
    7,485
    Likes Received:
    3,675
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    IT Managment
    Location:
    The Ozark Mountains of Missouri
    http://e-brewing.tumblr.com/

    read down at Fun With Heat Elements and Math

    he has done some work on the subject with electric only

    The basic forums looks like this:
    target temp - start temp = temp rise needed
    temp rise needed / temp rise per hour provided by element * 60 minutes = minutes needed to reach target temp from start temp with element

    220v:
    Striking:
    (18766 BTU/h) / 83.4 = 225F / hour
    50F rise needed : 50F / 225F rise per hour * 60 min = 13 minutes to strike

    Boiling:
    (18766 BTU/h) / 62.55 = 300F / hour
    57F rise needed : 57F / 300F * 60 = 11.4 minutes to boil

    110v:
    Striking:
    (4691.5 BTU/h) / 83.4 = 56.25F / hour
    50F / 56.25F * 60min = 53 mins to strike

    Boil:
    (4691.5 BTU/h) / 62.55 = 75F / hour
    57F / 75F * 60min = 45.6 mins to boil

    2x 110v:
    Striking:
    (2 * 4691.5 BTU/h) / 83.4 = 112.5F / hour
    50F / 112.5F * 60min = 26.5 mins to strike

    Boil:
    (2 * 4691.5 BTU/h) / 62.55 = 150F / hour
    57F / 150F * 60min = 22.8 mins to boil
     
  6. fc36

    fc36 New Member

    Joined:
    Nov 19, 2013
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Chicago, IL
    See this: http://www.phpdoc.info/brew/boilcalc.html

    and also cross-referenced to my request today: http://www.brewersfriend.com/forum/viewtopic.php?f=7&t=1085

    One issue in the source code of that equation is that when both "Start Temp" and "End Temp" are in units of Farhenheit and "End Temp" exceeds 99F, it always throws an error message of "Start temp cannot be greater than End Temp" even when "Start Temp" is less than "End Temp". It only does it when "End Temp" is in triple digits >=100F and my guess is that it still error checking based on a maximum boiling point of 100C and doesn't recognize hot, but not boiling water temps of 100-212F.
     
  7. fc36

    fc36 New Member

    Joined:
    Nov 19, 2013
    Messages:
    5
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Chicago, IL
    All of that mattters, yes, but the main point is to give electric brewers a ballpark idea of how to size their element or what to expect when mashing, boiling, etc... Real world conditions aside, they'll only affect the difference between boiling with an aluminum pot and a PID heater and boiling with a keggle and a PWM heater by about 5-10%, which equates to only a handful of minutes either way.

    The more important aspects are insulation and elevation, but even those won't affect the heating times by more than an additional 10-15%. Still well within a ballpark limit of 20% to either side for heating with electric.
     
  8. Ozarks Mountain Brew

    Staff Member

    Joined:
    Nov 20, 2012
    Messages:
    7,485
    Likes Received:
    3,675
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    IT Managment
    Location:
    The Ozark Mountains of Missouri

Share This Page

arrow_white