Conversion Efficiency is over 100%. Possible? Explanation?

Discussion in 'Brew Sessions' started by maconmatt, Jun 24, 2013.

  1. maconmatt

    maconmatt New Member

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    I searched the forums and I even read through a similar incident of this happening, but it didn't completely answer my question.

    I need to preface my problem with a little history so this will make some sense:
    The last few batches i've done have ended up with horrible efficiency numbers. And as a result, my beers have been very light and thin. As a result, i adjusted my recipes to use an efficiency of 65%. I recently spoke with a local homebrewer, and we realized the major mistake I had been making. I had been batch sparging with strike water that was only 152º! I don't know where I had gotten that number, but obviously it was extremely too low. So, on this last batch, i corrected the mistake and added water that was 185º.

    My pre-boil efficiency this time came out to be 78%, and I was super pleased! Now, i realize that this number will drop a bit once i adjust future recipes for a higher efficiency. I'm thinking 70-72% is probably where i really will end up being...which is great with me!

    While my pre-boil efficiency was great and what i was hoping, my conversion efficiency number that I had taken before it was a bit puzzling. It was 110.5%. I'm not sure if this is even possible? I calculated it using the total amount of water that I used for mash/sparge/etc. I also took my wort reading from a well-mixed sample from all collected wort.

    I do have one theory that i think it could be, though:
    Once the runoff stream stopped, I had 6.5 gallons in the kettle, just as i expected. I assumed that i had run off all of the wort from the grain. Well, come to find out later on...my sparge actually had gotten stuck. I still had about .5 gallon of wort still in the MLT. So, I think i had a "concentrated" amount of wort in the kettle, as opposed to the full volume that I was supposed to have. That would skew my percentage up...correct?

    Does that make sense? Is that possible?

    Thanks in advance for any insight anyone can give!
     
  2. LarryBrewer

    LarryBrewer Active Member

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    Re: Conversion Efficiency is over 100%. Possible? Explanatio

    It could be a difference between the grain ppg entered on the recipe vs what was purchased. The ppgs vary slightly year to year. In this case, the ppg of the recipe might have been lower than the ppg of the real thing, giving you a gravity bonus. It could also be that more grain was mashed than expected (an extra pound perhaps?).

    Stay with the 70-72% number for now until you are sure, since some of the high conversion efficiency translated into higher pre-boil and brew house efficiency.

    If you left behind some wort in the MLT, that would count against pre-boil efficiency, but not your conversion efficiency. Any sugars left behind are a negative impact on efficiency (with the exception of conversion efficiency which looks at what happened in the MLT before lautering).

    I have noticed some variation in gravity readings of the first runnings and pre-boil. Good that you stirred well. Make sure the gravity reading is temperature corrected. If using a refractometer make sure to calibrate it before use.

    It sounds like you are on the right track! Efficiency can be a frustrating topic. One thing that was not mentioned yet is mash pH, and it weighs heavily into conversion efficiency. Our Mash and Water Chemistry Calculator produces mash pH estimates that use a state of the art engine written by Kaiser of Braukaiser - cool stuff. I recommend checking that out before your next brew (there is a link to that calculator in the Water section on the recipe).
     
  3. maconmatt

    maconmatt New Member

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    Re: Conversion Efficiency is over 100%. Possible? Explanatio

    Awesome! Thank you for your reply! I'll definitely check into it.
     
  4. Mark D Pirate

    Mark D Pirate Well-Known Member

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    This was helpful today , somehow ended up with over 110 % conversion with BIAB
    i usually achieve mid 90 %
    brewhouse is average 72-74 %
    nil chance of a stuck sparge and double checked my readings
    took a second sample , chilled to calibration temp again ....same readings .

    Must be a great batch of malt !
     
  5. Trialben

    Trialben Well-Known Member

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    I find I get better efficiency with Briess then wayermann in the few maltsters that I've tried joe white lowest the malt specks will give you an estimated extraction efficiency ppg. Brewkaiser is a scientific dude I was reading some of his stuff last night. He puts science behind brewing and if you want detail he's ya man. That's where I found the beano brew thread I posted in an attenuation test he did. Sorry don't want to go off thread on this...

    I use brew house efficiency when calculating recipes it seems ato be a reliable indicator of what,ppg to expect.
     
  6. Mark D Pirate

    Mark D Pirate Well-Known Member

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    That's what i'm getting at !
    my brewhouse has just spiked by over 8% , if i did something better i would like to work out how/ why so i can do it again , called the LHBS and PPG figures line up , requested grain was supplied at weight ( can't imagine them giving extra for free )
    must have got lucky .... extra litre in Fv
     
  7. Trialben

    Trialben Well-Known Member

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    So your mash efficiency was what 10 % higher ish? Your base was? What did you account for all mash liquor. Because I use a keg my measurements are 50/50 as no presice measurement no site glass I estimate according to rings on kettle that I know the measurements off if ya get me drift. Thumbs up to you anyhow mark in brew house it's always great when we have a win I say:p.
     
  8. Mark D Pirate

    Mark D Pirate Well-Known Member

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    it's like waking up next to a gorgeous woman , i did it somehow but want to understand how so i can do it again next week
     
    Trialben likes this.

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