Refractometer - Why Not In Fermented Beer?

[BOG]

I've been struggeling with a problem in my brewing for some time and thought I nailed it the Refractometer as the cuprit.

I measured some finished (fermented) beer from the fermentor and got 1.018 from the refract and 1.012 from the hydrometer.
This test was a Fresh wort kit (Amber ale). Started at 1.030 (very odd for it that low) finished at numbers above.

Today I've just completed a calibration test with my hydrometer vs Refractometer with water and Dex and found they tracked perfectly.

So why would fermented beer measure differently from device to device ? (Note temp is not in play here. Covered that)

There was some comments earlier here that you cannot use a Refractometer for fermented beer for some reason. Why?


The Refract is from Ross (a good one obviously) and measures Brix and SG.

Anyone?



BOG

 

[RdeVjun]

Basically, alcohol corrupts the measurement as it refracts light differently to water. I think it is a well- know phenomenon and there's a means to calibrate for it, however I'm not sure how that can be done as I don't use one (I would like to though!).

Hope this helps! :icon_cheers:

 

[praxis178]

I've been struggeling with a problem in my brewing for some time and thought I nailed it the Refractometer as the cuprit.

I measured some finished (fermented) beer from the fermentor and got 1.018 from the refract and 1.012 from the hydrometer.
This test was a Fresh wort kit (Amber ale). Started at 1.030 (very odd for it that low) finished at numbers above.

Today I've just completed a calibration test with my hydrometer vs Refractometer with water and Dex and found they tracked perfectly.

So why would fermented beer measure differently from device to device ? (Note temp is not in play here. Covered that)

There was some comments earlier here that you cannot use a Refractometer for fermented beer for some reason. Why?

As mentioned it's the alcohol in the finished beer that's the problem.

Beersmith (and most other brewing programs) has a refractometer tool that compensates for the alcohol, so long as you input the OG so it knows/can work out how much alcohol to compensate for.

 

[BOG]

I been chasing why my beers finish so high.
My suspect is the refractometer.

So what your saying is that you cannot measure fermented wort and get an accurate reading.

I've got beersmith so I'll try to work out how the refractometer tool works. That may end up being a second post.



BOG

 

[Josh]

There's a few online calculators out there.

Here is one example onebeer.net

This site has plenty of other calculators to keep you going Brewheads

I've got a chart in the form of an excel spreadsheet. Not sure where I found it. Try a google search of this forum.

 

[Thirsty]

Hi

I found this site very usefill. Can download a copy of the excel spreadsheet discussed.

http://morebeer.com/learn_vids/vids_refract

Hope this helps

Thirsty

 

[BOG]

This spreadsheet and the tools from Josh seem to be to convert BRIX to SG.

The Refract I have is calibrated in SG. So I'm confused.

Does anyone know how to use the Beersmith tools.

Example: SG of a english ale was 1.048, my final was 1.030. What do I enter where?



BOG

 

[Cortez The Killer]

Here's a chart I put together

Cheers

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

 

[Wolfy]

Does anyone know how to use the Beersmith tools.

Example: SG of a english ale was 1.048, my final was 1.030. What do I enter where?

Open BS, then Refractometer tools.
Enter your original refractometer reading and select 'Unfermented wort gravity'
Then it should spit out exactly the same value your hydrometer measured OG.

Now enter your final refractomer reading, select 'Finished beer ABV/OG' and enter your OG value.
Now the result should be the same as you measured for your final gravity with the hydrometer.

 

[Screwtop]

This spreadsheet and the tools from Josh seem to be to convert BRIX to SG.

The Refract I have is calibrated in SG. So I'm confused.

Does anyone know how to use the Beersmith tools.

Example: SG of a english ale was 1.048, my final was 1.030. What do I enter where?



BOG

Beersmith requires the input in Brix so enter that, or use the close enough 4 times thing. So OG 1.048 Refractometer reading in Brix 7.5 = FG of 1.018

Screwy

 

[chris.taylor.98]

And here is a shameless plug for brewtoolz that pretty much does what the other tools do.

http://www.brewtoolz.com/tools/refract

The only think I can offer above and beyond is if you can think of a way to make it better I can change it.

 

[chris.taylor.98]

And here is a shameless plug for brewtoolz that pretty much does what the other tools do.

http://www.brewtoolz.com/tools/refract

The only think I can offer above and beyond is if you can think of a way to make it better I can change it.

And while I am at shameless plugging you can even enter your gravity readings directly in the brewlog part from the refractometer reading and it will correct it for you as it already knows the OG.

 

[pdfarrell]

Noobie refractometer question:

I understand how if you know your OG you can then take a reading of the femented wort, and using various tools/formulae, you can work out corrected FG.

My question is... Can you take the reading after the beer is carbonated ?

 

[raven19]

Yes you can, however make sure there is no bubbles in the sample (leave a portion to warm in a glass - give it a swirl, etc to drive out the CO2 quicker).

 

[pdfarrell]

Thank Raven, I assume taking the sample post filtering does not matter?

 

[raven19]

Correct, there will be less yeast in suspension which might 'slightly' effect the reading, but it will be pretty darn close still. You could do a before and after filtering test to check though!

Edit - noting that the alcohol will skew your FG reading and as such will need to be adjusted accordingly as per the links suggested above.