# Refractometer Chart During Fermentation



## Cortez The Killer (24/8/07)

I was a little bored at work today 

So I put together this chart for determining where your fermentation is up to / finishes

When only taking refractometer readings (so you can throw your hydrometer away!)

It has provision to change the temperature - it is set to 20*C - as most refractometers have ATC and 20*C is the calibration point

The chart runs from OG's 1.079 to 1.029 (19-7.2 Brix) but can be easily extended (with some basic excel skills) should you require numbers outside this range

It currently sits on three pages - so if anyone can think of a way to condense the info - that'd be great

I found going back to a computer after taking a reading during fermentation a little cumbersome - so this should be handy

My formulas came from here http://www.primetab.com/formulas.html

Any corrections / noted errors would be appreciated 

Also any thoughts as to any improvements would be good too

Cheers

Edit: Fix spelling in chart 

View attachment Refractometer_Chart___During_Fermentation___Brix_to_SG.xls


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## facter (24/8/07)

that my friend, is awesome.


This is going to be a fixture on my brewing wall. many many thanks!


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## Rabbitz (24/8/07)

Cortez

Good work.

Cell A2 should probably read Starting not Staring.

Rabz


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## Cortez The Killer (24/8/07)

Rabbitz said:


> Cortez
> 
> Good work.
> 
> ...



Thanks 

Fixed!!!  

Cheers


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## Screwtop (24/8/07)

Love your work!


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## Thirsty Boy (24/8/07)

Thanks Cortez, thats great.


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## PostModern (24/8/07)

Very handy :beerbang: Cheers!


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## Guest Lurker (24/8/07)

That is an interesting chart when you see it laid out like that. Seems like the old trick of working out what gravity a commercial beer started at, by measuring both hydrometer gravity and Brix in the finished beer, is most effective in a beer that finishes high.


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## Goat (27/8/07)

When I punch in 12.2 Brix into my version of Promash, it comes up with 1.047 as an SG - compared with 1.050 on this spreadsheet. Is that what most people are getting ? 

I think I may have stuffed up something in my setup... (it would certainly explain a few things)

The 'Brix Correction Factor' is set at the default 1.040 on my copy.


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## Cortez The Killer (27/8/07)

There is a discussion about this issue here http://www.aussiehomebrewer.com/forum/inde...l=refractometer

Apparently Promash uses a different formula

I couldn't find anything conclusive 

If anyone knows what the formula should be please advise

I'll correct the template

I pretty sure that mine matches the chart made by Doc

Cheers


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## Goat (27/8/07)

Yeah - thanks Cortez. 

I remember that thread - but I don't think it ever fully resolved the Promash issue, it was more about stable readings and temps. I might try the full blown refracto calibration setup. Just have to find a hydrometer and calibrate (check ) that first


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## etbandit (31/8/07)

Great stuff cortez!!!

Have you used it in practice, and how accurate is it compared to actual hydrometer readings of beer during fermentation?

Has anyone test it?


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## Cortez The Killer (31/8/07)

I haven't used a hydrometer for a long time - so i haven't verfied values

Previously i was using promash to tell me where fermentation was up to

And there is a website that has the caculator - http://brew.stderr.net/refractometer.html

Cheers


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## bonj (31/8/07)

Awesome work!

I have taken the liberty of reducing it to a single page (very small numbers). Here is the link to the PDF created with open office: LINK

I have printed it out on a laser printer, and the numbers are legible to me. I can't guarantee they will be for anyone else, or on inkjets, but it's worth a try.

-Bonj

edit: spelling, of course


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## Cortez The Killer (12/9/07)

I had a crack at dumping it into PDF as well

I managed to get the numbers a little bigger

Cheers 

View attachment Refractometer_Chart___During_Fermentation___Brix_to_SG___Revision_12_09_07.pdf


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## Cortez The Killer (14/11/07)

I thought I'd post this link here in case anyone wants to analyse 

Which is the most correct formula for converting Brix to SG

http://www.basicbrewing.com/radio/xls/BrixPlatoSG.xls

Cheers


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## Cortez The Killer (3/7/08)

I've been going through the refractometer brix to SG information again and noticed that goatherder makes an interesting point here - basically to the effect that the formula is deficient and lacks ^2 and ^3 at key points. 

This problem is also noted here http://www.basicbrewing.com/radio/xls/BrixPlatoSG.xls

The formulas I originally used for converting Brix to SG apply to a sucrose solution as BrissyBrew notes here - as wort has other components in it the formula I used was overstating the opening specific gravity

After reading and comparing formulas I've decided to run with the formulas which drive this page http://brew.stderr.net/refractometer.html

Brix to SG: 1 + (brix.value / (258.6 - ((brix.value / 258.2) * 227.1)
SG During Fermentation: ((1.001843 - 0.002318474*ob - 0.000007775*ob*ob - 0.000000034*ob*ob*ob + 0.00574*fb + 0.00003344*fb*fb + 0.000000086*fb*fb*fb) 
where ob=opening brix, fb=fermenting brix

The first formula gives the same results that the BYO formula would have given if the powers were included and appears to be most correct

I've updated the spreadsheet I'd created and have attached the one with formulas and a printable version that fits on an A4 page

Please disregard any previous versions of the spreadsheet - sorry for the inconvinience 

Cheers 

View attachment Printable___2008_07_03_Refractometer_Chart___During_Fermentation___Brix_to_SG.xls


View attachment 2008_07_03_Refractometer_Chart___During_Fermentation___Brix_to_SG.xls


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## kabooby (18/7/08)

I will give that a go Thirsty. Reading is clear enough its just that it is always high. Even after cooling it down. Last brewday I cooled some wort down in a jug by leaving it for 20 min. Took several refractometer readings all at 15 brix and the hydro reading was at 1054. Maybe its possible to be calibrated at 0 but be off at a higher reading.

I have been using the chart that Doc created. I might have to put a correction factor in beersmith and use that. Does anyone else do that or do they all go off the charts.

Could just be cheap crap

Kabooby 

Edit: Oops wrong thread


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## jonocarroll (13/1/10)

Digging up an old thread, I know, but cheers Cortez - I was just looking around for a chart exactly like this (with the intention of making one if I couldn't find one), and Google pointed me in your direction. Also cheers to Bonj for getting it sorted onto a single page. This one's getting laminated and stuck to the ferment fridge - I got sick of having to start up the computer to check the ferment progress in BeerSmith.

FWIW, the data point I was looking up matches between BeerSmith and the latest spreadsheet. :beer:


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## kirem (13/1/10)

I use the morebeer spreadsheet

http://morebeer.com/learn_vids/vids_refract


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## fraser_john (13/1/10)

kirem said:


> I use the morebeer spreadsheet
> 
> http://morebeer.com/learn_vids/vids_refract



+1


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## jonocarroll (13/1/10)

kirem said:


> I use the morebeer spreadsheet
> 
> http://morebeer.com/learn_vids/vids_refract


Which is fine if you have a computer handy... my point was that the table above can be stuck to the ferment fridge. Until now I've use the refractometer tool in BeerSmith.


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## kirem (13/1/10)

QuantumBrewer said:


> Which is fine if you have a computer handy... my point was that the table above can be stuck to the ferment fridge. Until now I've use the refractometer tool in BeerSmith.



true if you have beersmith handy  

I like to record my fermentation progress and the morebeer spreadsheet allows me to do that as well as the calculation. I can then detect a ferment that may be slowing down.

having said that, I have downloaded and laminated the sheet for ease of use 

thanks to cortez and bonji boy. :beer:


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## Cortez The Killer (13/1/10)

Fellas

Have created a wiki entry with a PDF version of the final chart for easy download and printing

http://www.aussiehomebrewer.com/forum//ind...showarticle=113

Cheers


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## pdilley (13/1/10)

I like the handy nature of a printed chart as I also at times do not have the computer handy so +1 on the charts.

Cheers,
Brewer Pete


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## KillerRx4 (13/1/10)

kirem said:


> I use the morebeer spreadsheet
> 
> http://morebeer.com/learn_vids/vids_refract



+ I use it on my phone, so its always in my pocket (windows mobile)


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