Author Topic: Improved Refractometer Correction calculator  (Read 8748 times)

Offline Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #135 on: February 09, 2018, 01:44:01 PM »
I placed this EDIT above, but here it is again because it matters:

FYI, I add a constant 0.001 to every result when using the Old Cubic.  A little tweak like that can make a real difference in our judgment of it.  The curvature is not affected, just the vertical placement on the graph.

My observation, when taking into consideration that I am interested only in final gravity and last 4 points preceding it (for accurately transferring beer with extract to packaging), is that most of the graphs converge at or near final gravity. The issue with that then is that if the Old Cubic and Novotny equations estimate a lower FG with a constant input (Original Bx), it would jive with some of the numbers I have now, i.e. unrealistic attenuation based on empirical findings.

I'll have to track this over some batches and see what happens.
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Offline gradys

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Re: Improved Refractometer Correction calculator
« Reply #136 on: February 09, 2018, 04:15:56 PM »
^^^^
Just realized: spreadsheet? Your Excel problem is solved, then?

And which spreadsheet are you using?  The one in Brewer's Friend that wants 30 samples?!

FYI: You can also determine Refractometer Correction Factor online here: https://www.homebrewmap.com/en/tools/calculators/refractometer-correction-factor

Offline klickitat jim

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Re: Improved Refractometer Correction calculator
« Reply #137 on: February 09, 2018, 06:39:12 PM »
Yeast suspension effect posted in a new thread under general topics

Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #138 on: February 14, 2018, 09:08:02 PM »
Trusting Novotný enough that I'm doing current batch without bothering with hydrometers.  Just checked mid fermentation, and OP's calculator with Novotný shows gravity exactly where it always is at this point with this beer. 
Rob Stein
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Offline klickitat jim

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Re: Improved Refractometer Correction calculator
« Reply #139 on: February 14, 2018, 09:26:22 PM »
Awesome

Offline Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #140 on: February 15, 2018, 12:26:03 AM »
Trusting Novotný enough that I'm doing current batch without bothering with hydrometers.  Just checked mid fermentation, and OP's calculator with Novotný shows gravity exactly where it always is at this point with this beer.

I added the novotny equations to the Terrill sheet and will be tracking from now on. I have a suspicion that the Terrill equations are more accurate at higher levels of attenuation.
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Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #141 on: February 15, 2018, 12:43:14 AM »
Trusting Novotný enough that I'm doing current batch without bothering with hydrometers.  Just checked mid fermentation, and OP's calculator with Novotný shows gravity exactly where it always is at this point with this beer.

I added the novotny equations to the Terrill sheet and will be tracking from now on. I have a suspicion that the Terrill equations are more accurate at higher levels of attenuation.

Could be, I'll look forward to your reporting on that.  Since I don't need to know when to spund,  I'm really just checking midway and at the end of fermentation to make sure there hasn't been some irregularity that would indicate the need to get a fresh culture of yeast.  So consistency is more important to me than accuracy.
Rob Stein
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Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #142 on: February 15, 2018, 03:22:08 PM »
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.
Rob Stein
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Offline Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #143 on: February 15, 2018, 03:25:29 PM »
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Terrill New Cubic or New Linear? New cubic tracks a bit higher than New Linear.

What was the O.G.?
“We are what we repeatedly do. Excellence, therefore, is not an act, but a habit.” Aristotle

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Offline dmtaylor

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Re: Improved Refractometer Correction calculator
« Reply #144 on: February 15, 2018, 03:36:34 PM »
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Are you very confident in your correction factor?  Did you check calibration of both the hydro and refract in plain cool water before measuring?
Dave

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Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #145 on: February 15, 2018, 04:42:46 PM »
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Are you very confident in your correction factor?  Did you check calibration of both the hydro and refract in plain cool water before measuring?
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Terrill New Cubic or New Linear? New cubic tracks a bit higher than New Linear.

What was the O.G.?


OG 12.7°P, whatever Terill is in th OP's calculator, yes, yes, and yes to Dave's questions.  I've had one other sample (fully fermented, different batch of same beer) give identical results.

At this point I have no problem with using a hydrometer at racking if I want a good FG.   I see no inaccuracy on wort, so the refractometer I will use to simplify brew day.  And I'll only have one reading, FG, to convert to (my preferred) Plato.
Rob Stein
Akron, Ohio

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Offline Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #146 on: February 15, 2018, 04:55:02 PM »
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Are you very confident in your correction factor?  Did you check calibration of both the hydro and refract in plain cool water before measuring?
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Terrill New Cubic or New Linear? New cubic tracks a bit higher than New Linear.

What was the O.G.?


OG 12.7°P, whatever Terill is in th OP's calculator, yes, yes, and yes to Dave's questions.  I've had one other sample (fully fermented, different batch of same beer) give identical results.

At this point I have no problem with using a hydrometer at racking if I want a good FG.   I see no inaccuracy on wort, so the refractometer I will use to simplify brew day.  And I'll only have one reading, FG, to convert to (my preferred) Plato.

The OP calculator uses Terrill New Linear. New Cubic actually tracks closer to what you saw @ 1.0116
“We are what we repeatedly do. Excellence, therefore, is not an act, but a habit.” Aristotle

"Messieurs, c’est les microbes qui auront le dernier mot." Louis Pasteur

Check us out at www.lowoxygenbrewing.com

Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #147 on: February 15, 2018, 05:00:10 PM »
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Are you very confident in your correction factor?  Did you check calibration of both the hydro and refract in plain cool water before measuring?
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Terrill New Cubic or New Linear? New cubic tracks a bit higher than New Linear.

What was the O.G.?


OG 12.7°P, whatever Terill is in th OP's calculator, yes, yes, and yes to Dave's questions.  I've had one other sample (fully fermented, different batch of same beer) give identical results.

At this point I have no problem with using a hydrometer at racking if I want a good FG.   I see no inaccuracy on wort, so the refractometer I will use to simplify brew day.  And I'll only have one reading, FG, to convert to (my preferred) Plato.

The OP calculator uses Terrill New Linear. New Cubic actually tracks closer to what you saw @ 1.0116

Thanks, that is probably within the margin-of-eyeballing-hydrometer-in-carbonated-beer error;  what calculator uses that new cubic?
Rob Stein
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Offline Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #148 on: February 15, 2018, 05:03:22 PM »
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Are you very confident in your correction factor?  Did you check calibration of both the hydro and refract in plain cool water before measuring?
^^^^^

Just took a sample of a fully fermented beer. Hydrometer: 1.012. Terill: 1.010. Novotný: 1.008.  Maybe I'll use refractometer on brew day, but maybe neither correction is really accurate on fermenting/fermented beer.  Look forward to more data.

Terrill New Cubic or New Linear? New cubic tracks a bit higher than New Linear.

What was the O.G.?


OG 12.7°P, whatever Terill is in th OP's calculator, yes, yes, and yes to Dave's questions.  I've had one other sample (fully fermented, different batch of same beer) give identical results.

At this point I have no problem with using a hydrometer at racking if I want a good FG.   I see no inaccuracy on wort, so the refractometer I will use to simplify brew day.  And I'll only have one reading, FG, to convert to (my preferred) Plato.

The OP calculator uses Terrill New Linear. New Cubic actually tracks closer to what you saw @ 1.0116

Thanks, that is probably within the margin-of-eyeballing-hydrometer-in-carbonated-beer error;  what calculator uses that new cubic?

Sean Terrill's Excel sheet uses it.
“We are what we repeatedly do. Excellence, therefore, is not an act, but a habit.” Aristotle

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Check us out at www.lowoxygenbrewing.com

Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #149 on: February 15, 2018, 05:06:35 PM »
Thanks, Big Monk, I'm looking at that right now.
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.