Mash Conversion

Discussion in 'General Brewing Discussions' started by Nugnut, Nov 13, 2017.

  1. Nugnut

    Nugnut Member

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    Yesterday I did my first double batch in my newly constructed Electric BIAB setup. I put through a Fat Yak.

    By the calculators on Brewers Friend I had a 86.67% conversion factor. Just being new to this is that good, bad or indifferent.

    I recirculated,at 68.9C then ramped to 75.6c then sparged with 5 litres of 75.6c.

    My gravity after this was 1.040. Unfortunately due to my concentration on the new toy I forgot to take the OG before pitching. After the boil and hop additions I should expect my OG to be higher than 1.040 shouldn't I?

    Thanks in advance for any help.
     
  2. Trialben

    Trialben Well-Known Member

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    I get 8-10 points out of a 60 minute boil Nugnut so I'd say your around 1.050 OG ish. You should get a full bodied ale from that mash temp. your efficiency will improve the more you brew on this rig.
     
  3. J A

    J A Well-Known Member

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    Depending on when and how you sampled gravity to get conversion factor, it could be accurate or not. It seems hard to get a really accurate gravity sample after mash and before boil. I don't know what your "double" batch volume is, but I'd be surprised if you actually had 86% plus with just a 5 liter sparge. Even recirculating and using a full fly sparge of 3 gallons in for a 5.5 gallon finished batch, I get high 70's. I find that OG measured just before pitch is the only accurate way of knowing exactly what you have.
    As Trialben says, 10 points higher in post boil gravity is common but that's completely dependent your boiloff. Your pre-boil gravity reading could be a little lower than you think and your boiloff could be a little low. I would expect that your OG is mid-40s at least, but it could have been lower than 1.050.
    You won't know your true system efficiency until you brew again and dial in you numbers. ;)
     
  4. Nosybear

    Nosybear Well-Known Member

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    Do you know your initial and final volumes? If so, you can calculate the FG: FG=OG*OV/FV. Use "points", the remainder after you strip the "1" off, in the formula above. Formula for points: Points=1000*(G-1) (G is any specific gravity).
     

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