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Old 04-26-2012, 04:20 AM   #1
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Default The numbers don't add up again...WHY?!?

The past two beers I've made have had the same problem. My pre-boil gravity is spot on. My pre-boil water volume is spot on. My post-boil water volume is spot on. Yet my post-boil into-the-fermenter original gravity is low. Isn't that kind of impossible?

Here are the details today:

------------------estimated -------measured

pre-boil SG---------1.040------------1.040

pre-boil H2O vol----7.0 gal-----------7.0 gal

post boil SG--------1.049------------1.043

post-boil H2O vol---5.25 gal----------5.25 gal

all estimates provided by beersmith 2.0, all measurements cross checked between hydrometer and refractometer, post-boil SG taken form two independent samples.


What is going on? I'm going crazy over this!


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Old 04-26-2012, 04:22 AM   #2
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It's the trub dude


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Old 04-26-2012, 04:56 AM   #3
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Quote:
Originally Posted by bottlebomber View Post
It's the trub dude
I thought of that. So I measured it. It's 2.5 quarts, and that includes all the solid matter. That means my total post-boil volume was 5.875 gallons. What it should've been, according to the software, is 5.82 gals. That's within the margin of measurement error, right? That's about 6 oz of water and, as I said, it includes the entire volume of solid hop debris. I think it's something else.
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Old 04-26-2012, 05:11 AM   #4
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volume differences based on different temperatures?
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Old 04-26-2012, 05:56 AM   #5
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Quote:
Originally Posted by AZ_IPA View Post
volume differences based on different temperatures?
I think BeerSmith takes care of that. Good suggestion, though. I guess it HAS to be a measurement error but it seems unlikely that I'd make the exact same error measuring two or three different batches over the course of a month. Nothing in my equipment has changed. I feel like I'm banging my head against a wall here and Lord knows I've already been doing that enough lately. If I could figure out where or what the measurement error is I could correct it but I have no idea why I'm off.
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Old 04-26-2012, 08:11 AM   #6
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I'm wondering this: does wort boil off at the same rate as water?
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Old 04-26-2012, 01:58 PM   #7
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Quote:
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I'm wondering this: does wort boil off at the same rate as water?
I would say it boils off faster. The more dissolved solids are in water, the lower the boiling point.
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Old 04-26-2012, 03:10 PM   #8
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You're definitely adjusting your hydro readings (using beersmith's lovely temp adjustment tool) to account for temperature? Hydro readings should all be adjusted to something like 62f or something.
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Old 04-26-2012, 03:48 PM   #9
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Is this with extract recipes? Any grains? All grain?
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Old 04-26-2012, 04:37 PM   #10
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If your volume measurements and thermometer are accurate, your measured post-boil OG is, shall I say, unpossible.

No way you can boil off nearly 1.75 gallons and only rise 3 gravity points.


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