Wort Shrinkage - no effect on water volumes?

Discussion in 'Recipe Editor' started by GPNewbrew, Jul 8, 2020.

  1. GPNewbrew

    GPNewbrew New Member

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    Why do we enter a value for Wort Shrinkage in the equipment profile? I have varied this number between zero and 10 percent, and it has no impact on the water calcs? Is this a bug or is it acting correctly? If it doesn't change anything, why make it an entry in the profile?

    I notice that when I add a percentage for wort shrinkage (say 4%) in Beersmith, it changes my water requirements, adding more water to my overall requirements.

    What is correct? Should I add a Misc loss in the profile to make up for this?

    Thanks, Bierbrur1
     
  2. Nosybear

    Nosybear Well-Known Member

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    If I understand correctly, it's applied when you create a recipe. If you change it afterward, well, Priceless, this is a behavior that might need looking into...
     
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  3. GPNewbrew

    GPNewbrew New Member

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    Not sure where you are trying to get to with your comment about changing it afterward; I made no mention of that!.

    You can enter 0, and it doesn't affect your water calcs or mash. The same when you set it at 10%. The way I figure it, the setting only tries to relate that the wort will be 4% more in volume (Assuming a 4% setting) when its heated up close to boiling.
     
  4. Pricelessbrewing

    Pricelessbrewing QA Software Tester
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    @Yooper Do you know what this setting affects? I'm with @GPNewbrew, I don't think it matters for recipe builder, QWR, and brew sessions have their own temp correction so IDK where this comes into play.
     
  5. Yooper

    Yooper Administrator
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    Boy, that's a new one on me.

    I think it does matter if you're taking your measurements hot vs cold, but in the water requirements it doesn't matter. That's because if you have 4% wort shrinkage when hot, you still draw your water cold and end with cooled wort, so it doesn't come into play. does that make sense?
     
  6. Nosybear

    Nosybear Well-Known Member

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    I don't see it as a factor because you are measuring water cold when you are adding it, your final volume is cold so all the shrinkage - it's real - from boil to fermentor is merely returning hot wort to cold. I can see it used in measuring the difference between post-boil (hot) and fermentor (cold) volumes. 5 gal cold would be 5 gal plus 3.2 ounces hot, too little for me to measure.
     
  7. Pricelessbrewing

    Pricelessbrewing QA Software Tester
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    It obviously matters in reality, but I don't think that user setting is actually being used anywhere.

    Fwiw my biab calculator uses engineering toolboxes thermal expansion curve for any temp correction, similar to the formula the brew session correction uses for volumes, but more accurate as the bf formula is linear I believe.

    This expansion formula is applied to mash volumes ( but not the water requirements), preboil volume, and postboil volume.

    So when calculating the water requirements, your postboil volume might be 5.5 gallons, but when measuring on brewday it'll be ~5.74.

    Your strike volume needed when measuring out your water would be 4 gallons at room temperature, but might be 4.1 gallons at strike temp.

    I'd prefer to not use any thermal expansion in the recipe builder, since that's more about designing the recipe than measured values, and only use it in the brew sessions adjustment. So I'd vote to remove the user setting.
     
  8. Nosybear

    Nosybear Well-Known Member

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    I'd second that, it's confusing and relatively useless since the inputs and outputs are both measured cold.
     
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  9. GPNewbrew

    GPNewbrew New Member

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    All good points! I originally started thinking about because I’m slowly moving away from Beersmith and migrating to Brewer’s Friend, and I couldn’t get the two softwares to produce the same water balances. Beersmith uses the cooling shrinkage in its calc, and Brewers Friend (BF), although you enter the parameter when you set up the equipment profile in BF, it ignores it in the water balance calls.

    it does create a pretty substantial number in a 5 gallon batch (25 oz), so it kept bugging me until I figured out what the difference.

    it does create a little issue which may eventually make me tweak my process a little. Usually, I don’t measure the water I add to my HLT. When it heats up to mashing temp, I measure as I transfer into the MLT, which means I’m looking at water at strike temp. I guess I theoretically could end up shorting myself when I xfer from kettle to fermenter, but I really haven’t noticed any issues.

    My vote is to remove the parameter from the equipment set-up. We have enough to worry about besides another setting that doesn’t mean anything!
     
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  10. Craigerrr

    Craigerrr Well-Known Member

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    I have wondered about this too, and had also played with the values the way GPN did and found no differences. Could it, should it reflect your post boil volume (Hot) vs. your fermenter volume (cold)? This may be splitting hairs though,which is why I never brought it up, but it is there, so it will be good to learn what its purpose is.
     
  11. Yooper

    Yooper Administrator
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    It may make a big difference to larger volume brewers, who pump hot water into their MLT or measure the hot volume in the brew kettle with a sight glass. But for me, with my 5-11 gallon batches, I measure cold going in and out, except in the brew kettle (where it doesn't really matter that much since I'm within 4% of the expected volume).
     
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  12. Nosybear

    Nosybear Well-Known Member

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    Exactly. And if you're close enough on the kettle that 4% would make a difference, you're boiling over anyway.
     

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