Refractometer?

[Aleman]

Remember that ATC ONLY compensates for the difference of the instrument temp and its calibrated temp . . . NOT the Sample temp . . .You still have to let the sample cool, and even with such a small sample it can take 30-60 seconds . . . The digital ones show this quite well, in that you put a sample in the well . . . and press read until you get three samples the same

[jmc]

Remember that ATC ONLY compensates for the difference of the instrument temp and its calibrated temp . . . NOT the Sample temp . . .You still have to let the sample cool, and even with such a small sample it can take 30-60 seconds . . . The digital ones show this quite well, in that you put a sample in the well . . . and press read until you get three samples the same

My manual refractometer says its ATC, but initially I was getting unreliable results. I found that if temp had changed more than 2C since I last calibrated the (zero) calibration reading was out. As its in the garage temp varies a lot.

Now I calibrate with cold tap water each session I use it before taking a proper reading.
It takes less than a minute to calibrate.

[jmc]

Yes you have to allow for alcohol as it affects Refractometer readings.

I use a print of an Excel sheet that converts Brix from Refractometer to SG based on OG and current SG in brix.

Any chance of a copy, or a link?

Its an Excel sheet I created based on the math in the Excel file to calc SG called refractbeer.xls that used to be on the MoreBeer.com site.
Currently Google still have a link to original file but I can't find it listed on MoreBeer site itself.

I did a large version with all sorts of OG & FG, but found I only needed to use 1 page for OG/FG in typical range for brewing beer.
File called: refractbeer_JMc-TypicalBeerRange.xls

I've uploaded my version as Excel and as a PDF & JPG in case anyone who doesn't have Excel wants to use it.


If you put in your OG as Brix in cell B4 it highlights the row you should be looking at for calculated SG based on subsequent Brix measurement (on top) you've taken during the brew.

As mentioned I calibrate my refractometer before each session so I don't bother with entering current temperature.

[oldbloke]

Many thanks!

[LeeH]

Yes you have to allow for alcohol as it affects Refractometer readings.

I use a print of an Excel sheet that converts Brix from Refractometer to SG based on OG and current SG in brix.

Any chance of a copy, or a link?

Its an Excel sheet I created based on the math in the Excel file to calc SG called refractbeer.xls that used to be on the MoreBeer.com site.
Currently Google still have a link to original file but I can't find it listed on MoreBeer site itself.

I did a large version with all sorts of OG & FG, but found I only needed to use 1 page for OG/FG in typical range for brewing beer.
File called: refractbeer_JMc-TypicalBeerRange.xls

I've uploaded my version as Excel and as a PDF & JPG in case anyone who doesn't have Excel wants to use it.


If you put in your OG as Brix in cell B4 it highlights the row you should be looking at for calculated SG based on subsequent Brix measurement (on top) you've taken during the brew.

As mentioned I calibrate my refractometer before each session so I don't bother with entering current temperature.

Top post!!!

[Charles1968]

There's also an online calculator here:
http://www.northernbrewer.com/refractometer-calculator/

[guypettigrew]

The online calculator is superb--thanks Charles1968. It's in my favourites list now.

Guy

[guypettigrew]

Ah, now I'm not so sure about the converter. Either the online or table one.

When I look into my refractometer the scale shows me a Brix reading of 13 is in line with a gravity reading of 1.051. The conversion table above, and the online converter give me 1.053.

Any thoughts, gentlemen?

Guy

[Aleman]

The calculator I trust is the one developed by Sean Terril, links earlier in thread. As I and others mentioned earlier you cannot trust the majority of the dual scale refractometers. You need to develop a 'fudge' factor ( generally around 1.04) and use that in the calculation. It accounts for the different RI of fructose/sucrose and maltose. The refractometer is intended to measure fructose levels in fruit juice . . . We are measuring maltose . . . And varying amounts of that in the wort (s)

[paulg]

aleman
you mention the fudge factor,for some reason my refractometer (old chinese type ) and new digital hanna one always seem to need a factor of about 0.966 not quite sure why.
I have checked my hydrometer at 20c with distilled water and zero the digital every time I use it.
not overly worried but any idea why?

[LeeH]

The online calculator is superb--thanks Charles1968. It's in my favourites list now.

Guy

This is a better one apparently.

http://seanterrill.com/2012/01/06/refra ... mment-2131

[Charles1968]

aleman
you mention the fudge factor,for some reason my refractometer (old chinese type ) and new digital hanna one always seem to need a factor of about 0.966 not quite sure why.
I have checked my hydrometer at 20c with distilled water and zero the digital every time I use it.
not overly worried but any idea why?

According to braukaiser on the Brewersfriend website the wort correction factor varies from instrument to instrument, and you need to log readings from about 20 brews (cross checking with an accurate hydrometer) to figure out your instrument's own wort correction factor:
http://www.brewersfriend.com/how-to-det ... on-factor/

Just to make things more complicated, the WCF will also vary with different grain bills.

I thought a refractometer would make brewing simpler, but it's had the opposite effect. One positive point is that I've discovered my hydrometer is two points out.

[Charles1968]

Ah, now I'm not so sure about the converter. Either the online or table one.

When I look into my refractometer the scale shows me a Brix reading of 13 is in line with a gravity reading of 1.051. The conversion table above, and the online converter give me 1.053.

Any thoughts, gentlemen?

Guy

Sorry, I should have posted one with wort correction factor included. The one in Aleman's link is good. Also this one on Brewersfriend:
http://www.brewersfriend.com/refractometer-calculator/

However, I seriously doubt the scale in your refractometer has factored this in correctly. I would disregard the gravity readings and stick to Brix.

[Rick_UK]

I thought a refractometer would make brewing simpler, but it's had the opposite effect.

I did take a punt on a 20 quid one from Amazon since posting this topic and I think Charles sums up my experiences to a tee.

I have had so much variation even with the same wort taken 20 mins apart (a few brix points) so don't really use it as the hydrometer is more accurate and less hassle. The refractometer is what Spike Milligan termed a 'technological regression'

Rick

[IPA]

The online calculator is superb--thanks Charles1968. It's in my favourites list now.

Guy

This is a better one apparently.

http://seanterrill.com/2012/01/06/refra ... mment-2131

I received a lab instrument to measure the SG as well as serum protein and RI for urine(http://www.sperdirect.com/lab-digital-r ... 9-prd1.htm).
Do you believe the RI for Wort or Wine RI would be similar enough for me to use ?
How would I approach a correction factor for urine vs wort ?

Presumably the RI for urine is the same as that for a lot commercial lagers.