Pre boil gravity close and OG way off

Discussion in 'Homebrewing' started by Alteredstate, Mar 20, 2016.

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  1. Alteredstate

    Alteredstate Initiate (0) Mar 5, 2015 New Jersey

    I brewed a Black IPA AG 5 gallon batch yesterday and my pre boil gravity was low by 3 points. I cooled the wort to 63 F before checking with my hydrometer and BS said OG should have been 1073 and actual was 1060? I use BS and I have my effienciency set for 68. The only thing that had changed yesterday was I used 5 oz of corn sugar at 10 min to dry the beer out some. My volumes were all the same as usual. My last IPA OG was low as well but the beer turned out good. I take my time batch sparging always hit my mash temp, could this be something is off with BS calculations or my settings? I did have my pre boil column set for 8.25 gallons but I ended up with 7.95
     
    #1 Alteredstate, Mar 20, 2016
    Last edited: Mar 20, 2016
  2. DavidlovesCBC

    DavidlovesCBC Initiate (0) Jan 25, 2014 Florida

    hmm BS may be off, or your Mash pH was off, or the grains were not crushed well. many things. post the recipe, that may help with seeing whats up. not hitting your marks is not terrible, you will still have beer. just not on the marks you wanted. next time you can always add some DME to hit your target OG
     
    #2 DavidlovesCBC, Mar 20, 2016
  3. pittvkyle7

    pittvkyle7 Initiate (0) Apr 16, 2007 Connecticut

    Efficiency usually goes down with higher gravity worts. I know that I have to calculate a lower effiencency with a 1.070 wort.
    In your case, your efficiency is even worse because you didn't collect enough volume. Your crush and mash ph are the easiest places to make improvement in this area.
     
    #3 pittvkyle7, Mar 20, 2016
  4. Alteredstate

    Alteredstate Initiate (0) Mar 5, 2015 New Jersey

    Here is the recipe I used

    5 gallon batch

    6.5 lbs pale ale 2 row
    6.5 lbs Maris otter
    .75 carafa III special dehusked
    .75 caramel 20 L
    .88 cara pills dextrine
    Mash temp 152( hit my mash temp and it stayed at 152 after 1 hr)

    vorloufed then I collected 3.5 gallon first runnings. I then added 170 degree sparge water, stirred the grains then let it rest for 15 minutes before I collected 2nd runnings.

    Hops
    Columbus 1.25 @60
    Amarillo .50 @15
    Simcoe 1.25 @5
    Amarillo 1.25 @ 5
    Simcoe 1.00 @FO
    Amarillo 1.00 @FO
    Columbus .25 @ FO

    Collected 6 gallons of wort and pitched 2 packs of WL WP 001 at 68 F after 10 hrs the beer is cooking nicely

    I didn't check mash PH as I am trying to learn more about additions of acids.
     
    #4 Alteredstate, Mar 20, 2016
  5. Alteredstate

    Alteredstate Initiate (0) Mar 5, 2015 New Jersey

    I spoke to the LHBS about the crush and they stated many of they're brewers are getting good efficiency with the same crush
     
    #5 Alteredstate, Mar 20, 2016
  6. ryane

    ryane Initiate (0) Nov 21, 2007 Washington

    You have me confused,
    1. You say in your first post that you added corn sugar, yet in the recipe there is no mention of it
    2. what is your actual batch size target and how much went in the fermentor? You mention 5 gal, and 6 gal in different posts
      1. 5.0 gal @ 68% eff = 1073.
      2. 5.25 gal @ 68% eff = 1070 - your predicted number
      3. 6.0 gal @ 68% eff = 1064
    3. LHBS is always gonna say their crush is good, I wouldn't expect them to say otherwise
    4. What i think the answer is.....................You put 6 gal into your fermentor, without corn sugar, and got 64% efficiency that results in an OG of........................wait for it..............................:rolling_eyes:............................1060
     
    #6 ryane, Mar 20, 2016
  7. DavidlovesCBC

    DavidlovesCBC Initiate (0) Jan 25, 2014 Florida

    Or added the corn sugar after you measured gravity
     
    #7 DavidlovesCBC, Mar 20, 2016
  8. Alteredstate

    Alteredstate Initiate (0) Mar 5, 2015 New Jersey

    Sorry, I added 5 oz of corn sugar with 10 minutes left in the boil.
    The breakdown was:
    8 gallons of wort pre boil
    6.75 after 60 minute boil
    Just under 6.00 gallons into the fermenter
    My batch size in BS is 5.25 gallons
     
    #8 Alteredstate, Mar 20, 2016
  9. Brew_Betty

    Brew_Betty Initiate (0) Jan 5, 2015 Wisconsin

    6 gal into the fermenter and your calculated batch size is 5.25 gal?

    That's why the gravity is off. If you boiled off another 0.75 gal, the gravity would be close to what BS predicted.

    If the amount in the fermenter was 4.5 gal, then the OG would have been higher than predicted.
     
    #9 Brew_Betty, Mar 20, 2016
    OldSock and PapaGoose03 like this.
  10. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    Unless you are going for repeatability, OG and volume just need to be close...boil off can be predicted better with more batches....not a big deal for most beers...rdwahahb
     
    #10 GreenKrusty101, Mar 20, 2016
  11. Alteredstate

    Alteredstate Initiate (0) Mar 5, 2015 New Jersey

    I'm confused I thought batch size is what I want when the beer is done? So if I collect 6 gallons into the fermenter and I have .75 for my fermenter loss that's my 5.25 gallons. Am I missing something
     
    #11 Alteredstate, Mar 21, 2016
  12. Brew_Betty

    Brew_Betty Initiate (0) Jan 5, 2015 Wisconsin

    Batch size is the amount in the fermenter.
     
    #12 Brew_Betty, Mar 21, 2016
  13. Alteredstate

    Alteredstate Initiate (0) Mar 5, 2015 New Jersey

    I changed it to 6 gallons and it put the recipe with an OG of 1063 at 67 efficiency
     
    #13 Alteredstate, Mar 21, 2016
  14. PapaGoose03

    PapaGoose03 Grand High Pooh-Bah (6,057) May 30, 2005 Michigan
    BA4LYFE Society Pooh-Bah

    That .75 is a lot of loss to leave in the fermentor. Do you have that much trub as the reason to leave it behind?
     
    #14 PapaGoose03, Mar 21, 2016
  15. Alteredstate

    Alteredstate Initiate (0) Mar 5, 2015 New Jersey

    yes, that has been typical for my spiedel fermenter using 2 yeast packs
     
    #15 Alteredstate, Mar 21, 2016
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