Author Topic: Improved Refractometer Correction calculator  (Read 6648 times)

Offline dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3224
  • Two Rivers, WI
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #75 on: February 05, 2018, 02:28:08 PM »
What prompted me to pursue this was learning that suspended solids (yeast, hop matter, proteins etc) can render a hydrometer to be inaccurate by as much as 10 gravity points. That's no bueno. So how to confirm it's accurate? These solids don't effect refractometer accuracy, sooooo here I am. Plus less is needed for a reading. Plus it's much easier to see where the line is, at least for my eyes. Just explaining why I'm doing this, not trying to change anyone.

It can be dang near impossible to get a good reading on a refractometer if the beer is hazy.  For that I might actually resort to my trusty old hydro!  I have a hard time believing a hydro could be off by more than 2 points, much less 10 points.  It'd have to be a pretty mucky brew to have that kind of effect, wow.
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 dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3224
  • Two Rivers, WI
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #76 on: February 05, 2018, 02:28:53 PM »
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

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 Big Monk

  • Brewer
  • ****
  • Posts: 436
  • I am Derek Scott: General Knower Abouter
    • View Profile
    • Low Oxygen Brewing
Re: Improved Refractometer Correction calculator
« Reply #77 on: February 05, 2018, 02:31:46 PM »
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.
“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

  • Senior Brewmaster
  • ******
  • Posts: 1532
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #78 on: February 05, 2018, 02:34:47 PM »
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
Akron, Ohio

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

Offline Big Monk

  • Brewer
  • ****
  • Posts: 436
  • I am Derek Scott: General Knower Abouter
    • View Profile
    • Low Oxygen Brewing
Re: Improved Refractometer Correction calculator
« Reply #79 on: February 05, 2018, 02:43:54 PM »
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?
“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

  • Senior Brewmaster
  • ******
  • Posts: 1532
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #80 on: February 05, 2018, 02:48:24 PM »
^^^^
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, 02:55:23 PM by Robert »
Rob
Akron, Ohio

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

Offline Big Monk

  • Brewer
  • ****
  • Posts: 436
  • I am Derek Scott: General Knower Abouter
    • View Profile
    • Low Oxygen Brewing
Re: Improved Refractometer Correction calculator
« Reply #81 on: February 05, 2018, 03:05:02 PM »
^^^^
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.
“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 dmtaylor

  • Official Poobah of No Life.
  • *
  • Posts: 3224
  • Two Rivers, WI
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #82 on: February 05, 2018, 03:19:58 PM »
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

  • I must live here
  • **********
  • Posts: 8460
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #83 on: February 07, 2018, 10:28:32 PM »
Update: I am so impressed with the repeatability of my refractometer that I changed all of my recipes to °p

Offline Big Monk

  • Brewer
  • ****
  • Posts: 436
  • I am Derek Scott: General Knower Abouter
    • View Profile
    • Low Oxygen Brewing
Re: Improved Refractometer Correction calculator
« Reply #84 on: February 07, 2018, 10:45:51 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?
“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 klickitat jim

  • I must live here
  • **********
  • Posts: 8460
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #85 on: February 07, 2018, 10:58:40 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, 11:00:12 PM by klickitat jim »

Offline klickitat jim

  • I must live here
  • **********
  • Posts: 8460
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #86 on: February 07, 2018, 11:02:05 PM »
Would look like this in the end

Offline Big Monk

  • Brewer
  • ****
  • Posts: 436
  • I am Derek Scott: General Knower Abouter
    • View Profile
    • Low Oxygen Brewing
Re: Improved Refractometer Correction calculator
« Reply #87 on: February 07, 2018, 11:03:43 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.
“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 klickitat jim

  • I must live here
  • **********
  • Posts: 8460
    • View Profile
Re: Improved Refractometer Correction calculator
« Reply #88 on: February 07, 2018, 11:06:04 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, 11:08:51 PM by klickitat jim »

Offline Big Monk

  • Brewer
  • ****
  • Posts: 436
  • I am Derek Scott: General Knower Abouter
    • View Profile
    • Low Oxygen Brewing
Re: Improved Refractometer Correction calculator
« Reply #89 on: February 07, 2018, 11:48:37 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.
“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