Refractometer

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The simple equation is:

SG = 1.000019 + [0.003865613(Brix)+ 0.00001296425(Brix) + 0.00000005701128(Brix)]

A refractometer does not measure all fermentables in a wort however (a hydrometer does) to get an adjusted brix I divide it by 1.04- a number used by promash.

More information (from: http://www.byo.com/feature/1132.html)

Measurements of the specific gravity of wort using a refractometer will not agree with the measurements of gravity using a hydrometer. Brix refractometers are meant to measure the percentage of sugar in a pure sucrose solution. Since wort is not simply sugar and water, you need to make a small correction because of the non-sugar components of the wort. The correction factor is different for different breweries. Beers that are very dark or have a very high starting gravity may also require a different correction factor. To calculate your correction value, measure the specific gravity with your refractometer. Then chill a sample of your wort and measure the gravity with a hydrometer. Convert the hydrometer reading to Brix using the equation: Brix = (SG-1)/0.004. Then divide the reading of the refractometer by your actual hydrometer reading. You should have a number between 1.02 and 1.06. If you do this for several worts and average them, you will get a number that you can use for your brewery. ProMash defaults to 1.04 and this is the number I use. Once you have this number, divide all of your subsequent refractometer readings by your calibration number to get the actual reading. For example, if your reading is 14.6 Brix then your corrected reading is 14.04 Brix (14.6/1.04=14.04). Then, we can convert the measurement in Brix to specific gravity.

Once youve calibrated your refractometer and measured your wort correction factor, you can obtain a measurement of your specific gravity quickly, without having to cool enough wort for a hydrometer sample. You can use the refractometer to measure the gravity of your wort during run-off to help you to decide when to stop sparging. Likewise, you can quickly obtain your gravity anytime during the boil to determine if you need to keep boiling your barleywine or if adding water to your best bitter is in order.

With careful use, a 030 Brix refractometer is precise to within 0.20.3 Brix. As such, it is less precise than a good hydrometer. However, it can provide a quick measurement of gravity to within about one gravity point at times when cooling the wort for a hydrometer sample would take too much time.

Hope this helps.
 
crozdog said:
Attached is a spreadsheet I made and printed out to allow me to look up the conversions. I've put it in a plastic sleeve & use a fridge magnet to hang it on my keg fridge in the shed. Hope you find it useful

crozdog
Click to expand...


Crozdog - Since I started AGing I have been using Docs BRIX=SG conversion chart attached below. I have also attached another chart from an unknown donor. Both these charts closely follow each other in their calculations but I see that yours differs form them in a number of points of gravity i.e. 12 brix in Docs is 1.049 whilst 12 brix in yours is 1.0466.

It would be helpful if the difference between the charts could be explained. And Doc feel free to make comment also.

The efforts of those such as yourself who go to a lot of trouble to make these charts is greatly appreciated but I am sure that all of us who use them would like the benefit of the most accurate chart.


View attachment BRIX_CHART.pdf


View attachment Refractometer_Chart___During_Fermentation___Brix_to_SG.xls



Cheers, Hoges
 
Brix=(SG-1.000019)/ (0.003865613+0.00001296425+0.00000005701128) I used this to put the SG markings against the Brix, you can do a quick add up and work out the adjustment for colour and the conversion for sucrose.
SG = 1.000019 + [0.003865613(Brix)+ 0.00001296425(Brix) + 0.00000005701128(Brix)]
I did some research on the adjustment formulas out there, all based on sugar, with a few adjustments for the colour of the beer. I also played around with beersmith/promash refract calibration adjustments for color they all come out so close that for testing wort run off or getting a pre-fermentation reading on the wort the slight variations for different formulas is not gong to make any real difference.
 
I have a 32 Brix refractometer (from Ross) and two Carlton plato hydrometers (0-10P and 10-20P) tested accurate to 0.1P. I brewed three beers last week in the range of 10-12P and pale to copper colour and the readings come out within 0.1P every time.

I use the hydrometers for the "official" OG reading and post fermentation but the refractometer is fantastic for monitoring the gravity through the process so I can quickly recalculate water and hop additions while I'm brewing, and it's proven to be accurate enough.

Cheers, Andrew.
 
Hogan said:
Crozdog - Since I started AGing I have been using Docs BRIX=SG conversion chart attached below. I have also attached another chart from an unknown donor. Both these charts closely follow each other in their calculations but I see that yours differs form them in a number of points of gravity i.e. 12 brix in Docs is 1.049 whilst 12 brix in yours is 1.0466.

It would be helpful if the difference between the charts could be explained. And Doc feel free to make comment also.

The efforts of those such as yourself who go to a lot of trouble to make these charts is greatly appreciated but I am sure that all of us who use them would like the benefit of the most accurate chart.


View attachment 18558


View attachment 18559



Cheers, Hoges
Click to expand...
Hoges,
you'll see the formula I used at the bottom of the chart ie SG = 1.000019 + [0.003865613(Brix) + 0.00001296425(Brix) + 0.00000005701128(Brix)]. i sourced this from an article on BYO http://byo.com/feature/1132.html . This is the same formula as mentioned by Brissy & Tororm - who also mentions the same link :)

Can't comment deeply on the other charts as I unfortunately don't have the time to look at em now. There may be a difference with the chart for during fermentation due to the presence of alcohol. I only use my chart for unfermented wort. Doc, where did you source your formula?
 
Now I am thinking I might just get a Hydrometer with a Thermometer in it and tape the adjstment chart to the brew table. As I dont fly sparge I don't think it would help that much. Might wait and see what these new mashmaster ones are like though.


Steve
 
crozdog said:
Hoges,
you'll see the formula I used at the bottom of the chart ie SG = 1.000019 + [0.003865613(Brix) + 0.00001296425(Brix) + 0.00000005701128(Brix)]. i sourced this from an article on BYO http://byo.com/feature/1132.html . This is the same formula as mentioned by Brissy & Tororm - who also mentions the same link :)

Can't comment deeply on the other charts as I unfortunately don't have the time to look at em now. There may be a difference with the chart for during fermentation due to the presence of alcohol. I only use my chart for unfermented wort. Doc, where did you source your formula?
Click to expand...


Same here crozdog - only use the chart for unfermented wort. Sure would like to hear from Doc or any other chart provider as to why there is such a discrepancy in the values.

Cheers, Hoges.
 
Who cares if it's showing a gravity scale, or am I missing something?
 
You'll want one that goes higher than 1070, Steve. I think I got one from this seller.

No problems with it, turned up quickly and works fine.
 
Hogan said:
Same here crozdog - only use the chart for unfermented wort. Sure would like to hear from Doc or any other chart provider as to why there is such a discrepancy in the values.

Cheers, Hoges.
Click to expand...

The only real formula is from brix to SG for pure sucrose. The problem that follows from this is your beer is not clear like a glass of sugar water. The next problem is the adjustment between maltose and sucrose. All the formulas are based around adjusts for colour which have the greatest impact on the formula. If you play around with beersmith you will notice you can calibrate your refract, but really only of any use if your brewing the same beer over and over. The calibration tool adjusts for the colour and sugar composition of the wort. Most formulas are very close to each other and are calibrated using different beers. If you really wanted a smart program somebody would plot all the curves find the relationship between SRM, gravity and refraction and have a tool that provides approximate calibration on this, but if you using a hand held refractomter your calibration is not going to make a significant difference at the end of the day.

dual scale SG and Brix refrac.
 
I made this chart up a while back, printed it out and hung it up in the garage.

Its very close. I have checked it against a hydrometer reading many times and is always within a SG point and thats close enough for me.

Here is my chart...... i share :)

View attachment SG_to_Brix_conversion.xls
 
The simple equation is:

SG = 1.000019 + [0.003865613(Brix)+ 0.00001296425(Brix) + 0.00000005701128(Brix)]

A refractometer does not measure all fermentables in a wort however (a hydrometer does) to get an adjusted brix I divide it by 1.04- a number used by promash.
Click to expand...
I read through just about the entire thread because...

I used cortez the killer's spreadsheet after reading my wort and got a brix 6.2=1.014 when OG was 1.044.

The above quote gives me
6.2/1.4= 4.43

Promash gives -> 4.43 Plato= 1.017

My hydrometer reads 1.021 for a brix of 6.2.

I am confused.
:huh:

I decided to trust the hydrometer and took the pilsner out for a Diacetyl rest and hope it drops to 1.017 over 48hour and then I'll rack it.
Bloody oath I love my hydrometer.
 

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