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Author Topic: Improved Refractometer Correction calculator  (Read 40741 times)

Offline dmtaylor

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Re: Improved Refractometer Correction calculator
« Reply #75 on: February 05, 2018, 07:28:53 am »
Plus less is needed for a reading.

This was a biggie for me. I'm only putting 1.25 gallons into the fermenter and I don't recycle gravity samples so a hydrometer is a no-go for me.

Wow... I can see your schwarz is even smaller than mine!
Dave

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Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #76 on: February 05, 2018, 07:31:46 am »
Plus less is needed for a reading.

This was a biggie for me. I'm only putting 1.25 gallons into the fermenter and I don't recycle gravity samples so a hydrometer is a no-go for me.

Wow... I can see your schwarz is even smaller than mine!

It's the only way I can brew. 2 kids under 5, full-time job, and no dedicated brew space? I rely on short heat up and cool down times to even be able to brew. Also, I don't drink much, at least in a relative sense. 5-6 bottles a week.

Even with all that said, it's still tough to get more than one session per month in.

Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #77 on: February 05, 2018, 07:34:47 am »
I've been digging through textbooks trying to find any reference to use of anything but iodine test to confirm complete conversion (this was where I thought refracto might be in order.) Nada.
Rob Stein
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Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #78 on: February 05, 2018, 07:43:54 am »
I've been digging through textbooks trying to find any reference to use of anything but iodine test to confirm complete conversion (this was where I thought refracto might be in order.) Nada.

I mean, you don't really need a textbook to tell you there are other ways to determine conversion:

1.) You know your target gravity;

2.) There are resources (1) that show an approximate level of beta activity per step, so you know to look for a percentage of your extract after each mash step;

3.) If at the end of a mash you are getting significantly less extract than predicted (with losses, etc. factored in), you know your conversion was incomplete.

We've used the multi-step Brauwelt mash shown below on many occasions and have been able to reliably predict conversion through careful analysis of gravity at each step.

(1) Brauwelt International – Some reflections on mashing –  Part 1: http://www.lowoxygenbrewing.com/wp-content/uploads/2017/04/pkjdf.pdf and Part 2: http://www.lowoxygenbrewing.com/wp-content/uploads/2017/04/pddvxvf.pdf

At the end of the day though, what you are doing is working for you, and if it gives you the level of information that you require, then why change it?

Offline Robert

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Re: Improved Refractometer Correction calculator
« Reply #79 on: February 05, 2018, 07:48:24 am »
^^^^
Yep. Enough years of consistent RESULTS, if it ain't broke don't fix it.  There's a difference between a lab and a brewhouse.

EDIT I also keep forgetting that this is different for those of you doing no sparge, you have to know when the converted material has leached into the liquid.  As I'm doing a conventional sparge, that happens during said sparge, so I just need to know when saccharification is complete.  Iodine does that.
« Last Edit: February 05, 2018, 07:55:23 am by Robert »
Rob Stein
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Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #80 on: February 05, 2018, 08:05:02 am »
^^^^
Yep. Enough years of consistent RESULTS, if it ain't broke don't fix it.  There's a difference between a lab and a brewhouse.

EDIT I also keep forgetting that this is different for those of you doing no sparge, you have to know when the converted material has leached into the liquid.  As I'm doing a conventional sparge, that happens during said sparge, so I just need to know when saccharification is complete.  Iodine does that.

Right. We calculate target first wort gravity (maximum) based on Kai's equations, and the base our ACTUAL estimates of that. Actuals will depending on conversion and our losses.

Offline dmtaylor

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Re: Improved Refractometer Correction calculator
« Reply #81 on: February 05, 2018, 08:19:58 am »
It's the only way I can brew. 2 kids under 5, full-time job, and no dedicated brew space? I rely on short heat up and cool down times to even be able to brew. Also, I don't drink much, at least in a relative sense. 5-6 bottles a week.

Even with all that said, it's still tough to get more than one session per month in.

We digress, but I can relate.  I only have about 2 beers per week on average.  My 3 kids are a little older now but not by much -- 14, 13, and 10.
Dave

The world will become a much more pleasant place to live when each and every one of us realizes that we are all idiots.

Offline klickitat jim

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Re: Improved Refractometer Correction calculator
« Reply #82 on: February 07, 2018, 03:28:32 pm »
Update: I am so impressed with the repeatability of my refractometer that I changed all of my recipes to °p

Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #83 on: February 07, 2018, 03:45:51 pm »
Update: I am so impressed with the repeatability of my refractometer that I changed all of my recipes to °p

Yours reads °P or °Bx?

Offline klickitat jim

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Re: Improved Refractometer Correction calculator
« Reply #84 on: February 07, 2018, 03:58:40 pm »
Mine reads BrixWRI. That's one reason you do the correction factor, or so I'm told. Then you have °P I believe. And °P and the Spauling scale are the same until you get out about the 4th decimal

Anyway... I'll be looking at BrixWRI, converting to °P and comparing to my recipe.
« Last Edit: February 07, 2018, 04:00:12 pm by klickitat jim »

Offline klickitat jim

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Re: Improved Refractometer Correction calculator
« Reply #85 on: February 07, 2018, 04:02:05 pm »
Would look like this in the end

Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #86 on: February 07, 2018, 04:03:43 pm »
Mine reads BrixWRI. That's one reason you do the correction factor, or so I'm told. Then you have °P I believe. And °P and the Spauling scale are the same until you get out about the 4th decimal

Anyway... I'll be looking at BrixWRI, converting to °P and comparing to my recipe.

The correction factor is the conversion from RI to °Bx if I’m not mistaken. °Bx to °P is close enough to 1.04 for the gravities we have that I SWAG with that.

Offline klickitat jim

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Re: Improved Refractometer Correction calculator
« Reply #87 on: February 07, 2018, 04:06:04 pm »
I also believe it's needed for Kai's chart, since the column is labeled Plato. Entirely possible that folks who don't know their correction factor and compute displayed Brix to °P are not getting what they think they are getting

With my $17 refractometer, if it reads 10brix the corrected °P would be 9.9 so WAAAAAYYYYY off
« Last Edit: February 07, 2018, 04:08:51 pm by klickitat jim »

Big Monk

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Re: Improved Refractometer Correction calculator
« Reply #88 on: February 07, 2018, 04:48:37 pm »
I also believe it's needed for Kai's chart, since the column is labeled Plato. Entirely possible that folks who don't know their correction factor and compute displayed Brix to °P are not getting what they think they are getting

With my $17 refractometer, if it reads 10brix the corrected °P would be 9.9 so WAAAAAYYYYY off

I need to look at our spreadsheet. I made some changes today and I think I need to switch back. I think the correction IS the °Bx to °P conversion. I changed it today thinking I was wrong and now I think I was right.

Offline klickitat jim

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Re: Improved Refractometer Correction calculator
« Reply #89 on: February 07, 2018, 04:53:31 pm »
Here's what I'm going by
"How to Determine your Refractometer’s Wort Correction Factor

When taking a refractometer measurement of wort, the Brix reading is not necessarily accurate. What is obtained is the Brix WRI (wort refraction index).  Only after dividing the Brix WRI by the wort correction factor is the actual Brix known. It is helpful to know that Brix and Plato are nominally the same to 3 decimal places, so the corrected reading can be treated as Plato (°P).

The correction factor is needed because wort has a different density than sugar water which refractometers are designed for.  The wort correction factor is specific to the instrument."

From a Brewers Friend article explaining their correction factor spreadsheet

By the way, don't think that I did a bunch of work changing my recipes from SG to °P, it's just a click of a button, lol