Trying to do the work-around on why gravity would be consistently low

Discussion in 'Homebrewing' started by atomeyes, Sep 1, 2015.

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  1. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    help me out here.
    i just changed a few components on my system.
    finding that my gravity's consistently below target, which is new to me.

    what factors would result in lower than normal gravity? beer was to be 6.5% beer with a OG of 1.065. i hit 1.052. had system efficiency set to 77%. perhaps that is a bit too optimistic.
    it was a hot and humid day (30 C). maybe evapouration was slowed down?

    any other factors you can think of?
     
    #1 atomeyes, Sep 1, 2015
  2. VikeMan

    VikeMan Grand Pooh-Bah (3,067) Jul 12, 2009 Pennsylvania
    Pooh-Bah

    What did you change?

    Also, if evaporation was slowed down, you would have had a higher actual post-boil volume. If you know what that volume was, it's easy enough to find out what your post-boil OG would have otherwise been with the planned evaporation...

    ((OG - 1) * (Actual Volume / Planned Volume)) + 1
     
    #2 VikeMan, Sep 1, 2015
  3. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Did you change your mill at all?
     
    #3 dmtaylor, Sep 1, 2015
  4. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    not lately. i have a barley crusher. i did the width-of-a-credit-card adjustment and found that it would get stuck while milling. so i opened it a fraction more.
     
    #4 atomeyes, Sep 1, 2015
  5. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    new Blichmann kettle.
    it was probably around 5.3 gallons
     
    #5 atomeyes, Sep 1, 2015
  6. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    i'm also wondering if my copper manifold is trapping grains underneath it and not letting water get to it. not sure if that's a totally illogical thought.
     
    #6 atomeyes, Sep 1, 2015
  7. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    #7 atomeyes, Sep 1, 2015
  8. VikeMan

    VikeMan Grand Pooh-Bah (3,067) Jul 12, 2009 Pennsylvania
    Pooh-Bah

    The kettle should not have affected your mash efficiency.

    Is there a puddle of wort (besides normal grain absorption) sitting at the bottom of your tun after lautering?
     
    #8 VikeMan, Sep 1, 2015
  9. HerbMeowing

    HerbMeowing Maven (1,295) Nov 10, 2010 Virginia
    Trader

    Standard CC width reportedly is 0.039" ... the same width set at the BC factory.

    If the mill gets stuck with a tighter gap ... might could be time for cleaning.
    Pop off the plates and give the spindles some TLC and some lube.
    Take care removing the screws. The heads are soft and booger easily.
     
    #9 HerbMeowing, Sep 2, 2015
    GreenKrusty101 likes this.
  10. dmtaylor

    dmtaylor Savant (1,149) Dec 30, 2003 Wisconsin

    Besides the crush, the other major factor with efficiency calculations is the volume measurements. If in the past or present you were not totally nailing the pres or post boil volumes per your recipe, then your efficiency calculations will be messed up. Example: Your recipe says 1.060 for 5 gallons post boil. But you got 1.050 for 6 gallons. Could something like that be happening, just a lack of evaporation or oversparge kind of thing? Nail the volumes. Also think about whether your recipe calculations today might be more or less accurate than in the past.
     
    #10 dmtaylor, Sep 2, 2015
  11. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    cleaned it 2 months ago. lubed it with some canola oil (foodsafe, i figure).
    even yesterday, it froze on me once. i put the drill in reverse for a sec and it was fine after. my grist was all pilsner-like malt. all light.
     
    #11 atomeyes, Sep 2, 2015
  12. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    using beersmith, for good or for bad, for my calculations. using the sparge volumes and mash volumes directly off of BS.
    doubt i oversparge. i just wonder if my mash tun, which is just over a year old, is part of the problem. see my next post.
     
    #12 atomeyes, Sep 2, 2015
  13. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    it is wet. never bone dry.
     
    #13 atomeyes, Sep 2, 2015
  14. psnydez86

    psnydez86 Initiate (0) Jan 4, 2012 Pennsylvania

    I don't use a manifold but I believe those holes should be on the bottom of the cooler otherwise you will be leaving wort behind ( I would think). But if you've done it this way for years that doesn't explain a decreased efficiency.
     
    #14 psnydez86, Sep 2, 2015
  15. telejunkie

    telejunkie Savant (1,107) Sep 14, 2007 Vermont

    batch or fly sparge?

    I orient holes down with the thought that gravity might help aid in keep solids out of the holes...(?), but I know many folks that keep holes up. Also you should be able to get another quart or so of wort with holes down...
     
    #15 telejunkie, Sep 2, 2015
  16. Naugled

    Naugled Pooh-Bah (1,944) Sep 25, 2007 New York
    Pooh-Bah

    Is there a site tube on your new kettle for volume? Are you sure you calibrated it correctly?
     
    #16 Naugled, Sep 2, 2015
  17. Brew_Betty

    Brew_Betty Initiate (0) Jan 5, 2015 Wisconsin

    Beersmith is accurate if you have an accurate equipment profile. Your equipment profile is something you create based on taking accurate measurements of your system and process results.
     
    #17 Brew_Betty, Sep 2, 2015
  18. atomeyes

    atomeyes Initiate (0) Jul 13, 2011 Canada (ON)

    yes and no.
    blichmann does give you most of the specs needed for beersmith, but evap rate and volume loss in mash tun are inputs i need to make.

    i brewed today with a friend. his milled grains. my mash tun. left before boil. pre-boil readings were bang on.
    borrowing his mash tun for a monday brew. will see what happens with my #s
     
    #18 atomeyes, Sep 2, 2015
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