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Hydrometer VS Refractometer

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bradsul

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The refractometer can only be used pre-fermentation as it is only for measuring dissolved sugars in water. There are formulas for correcting post-fermentation but most guys say they are really inaccurate.

For the AG brewer a refractometer is a great way to take fast gravity readings during sparging, I don't think there's much point in one for an extract brewer.
 

Beertk

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Do you all grain? The refractomer, while usefull otherwise, is most usefull for checking sparge gravity. You don't need to cool the wort for long periods prior to getting acurate readings. You only need a drop or two and that cools as quick as you drop it to the glass prism. The hydrometer is best for checking final gravity. There is much debate about the usefulness of the refractomer one there is alcohol in the liquid. I recomend using both if you have the means.
 

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Yes, It is mainly a fly sparging tool. You can use it for checking gravity on any wort but it is most important when verifying that you don't over sparge. In my opinion the fly sparger gets the most benefit from this tool. I mainly batch sparge and I have one. I just like the speed and effectiveness of the tool. It is by all means not an essential tool from batching.
 

bradsul

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You can get them really cheap on ebay so I'd say go for it. Not having to wait for samples to cool even when batch sparging make them really worthwhile.
 

Beerthoven

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A refractometer is not for fly spargers only.

I'm a batch sparger and I use a refractometer to measure my pre-boil wort gravity. If I totally missed my target pre-boil gravity I can do something about it before the boil gets underway. With a hydro sample, I'd have to wait 15 or 20 minutes for the sample to cool. I also use it to measure OG post-boil.
 

Sherpa FE

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Beerthoven said:
A refractometer is not for fly spargers only.

I'm a batch sparger and I use a refractometer to measure my pre-boil wort gravity. If I totally missed my target pre-boil gravity I can do something about it before the boil gets underway. With a hydro sample, I'd have to wait 15 or 20 minutes for the sample to cool. I also use it to measure OG post-boil.
Hmmm...I also used one on Sunday, and when the pre-boil refractometer reading was taken, it showed low (1.044) when Beer Smith estimated it at 1.060 preboil.
So, where is the discrepancy then ? I undersatnd about the efficiency getting better as the total gallons are boiled down to the final amount.
Is there a general rule of thumb for example; if your pre-boil is supposed to be 1.060, and your refractometer is reading 11.0 brix (1.044) then do you add 15 points to it, making it 1.059?? Or is BeerSmiths refractometer section not fully supported??
 

Bearcat Brewmeister

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Beerthoven said:
A refractometer is not for fly spargers only.

I'm a batch sparger and I use a refractometer to measure my pre-boil wort gravity. If I totally missed my target pre-boil gravity I can do something about it before the boil gets underway. With a hydro sample, I'd have to wait 15 or 20 minutes for the sample to cool. I also use it to measure OG post-boil.
Why let a hydro sample cool? Don't you just correct the reading for temperature?
 

Sherpa FE

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Denny's Evil Concoctions said:
Hydrometers are less accurate the farther away from the calabrated temp.

Sherpa, is your refractomter auto temp compensating? (ambient air temp, not wort)
Not sure, whats the best way to find out?
I do have it out in the same conditions that I take a reading at. For example, it comes out of the A/C shop, and sits outside for at least an hour before I use it.
 

Schlenkerla

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Even ATC Refractometers have an upper limit. For accuracy you still need to cool to 85F.

Here's an excerp of the link below

However, if evaluations
are being made outdoors in the
heat, then it is important to adjust
the readings by a given factor provided
by the manufacturer. Newer
refractometers compensate for
fluctuations in temperature, but
are still only accurate within a
specified range of temperatures.
A range between 68-86ºF (20-
30ºC) is the most common for
temperature compensated (TC)
or automatic temperature compensation
(ATC) refractometers.
Refractometers with larger ATC
ranges are available, but are more
expensive.​

http://cemerced.ucdavis.edu/files/40177.pdf
 

Bearcat Brewmeister

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Schlenkerla said:
Even ATC Refractometers have an upper limit. For accuracy you still need to cool to 85F.

A range between 68-86ºF (20-
30ºC) is the most common for
temperature compensated (TC)
or automatic temperature compensation
(ATC) refractometers.

http://cemerced.ucdavis.edu/files/40177.pdf
Exactly. Neither is going to be 100% accurate once you get too far from its optimal temperature (60F for hydro, 68-86F for refractometer). By the time it goes through my hose at fly sparge speed to where I collect (at least on a 35F brew day), the temperature is usually around 140F.
 

feedthebear

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bradsul said:
The refractometer can only be used pre-fermentation as it is only for measuring dissolved sugars in water. There are formulas for correcting post-fermentation but most guys say they are really inaccurate.

For the AG brewer a refractometer is a great way to take fast gravity readings during sparging, I don't think there's much point in one for an extract brewer.
I when I bought my refract I double checked the refract reading vs. my last post-fermentation reading with the hydro. They were weren't that different. And I suspect for most small and medium beers, it won't. For big beers and wines, it will make a lot of difference.

But this is only in terms of determining an exact value for your abv. If your abv isn't that important to you and you only want to make sure you're fermentation is complete, it doesn't matter either way.
 
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Schlenkerla said:
Even ATC Refractometers have an upper limit. For accuracy you still need to cool to 85F.
Sigh.. It's the temperature of the Refractometer NOT the wort. That drop of wort is not going to put a dent in the refractometer temperature, so you calibrate based on the ambient temperature, as long as the refractometer has been in the same enviroment to match the ambient air temperature. (unlike a hydrometer)

And for the record. If you Properly calibrate A: your refractometer, B: your software, you will get an accurate reading on fermenting and fermented beer.
 

Sherpa FE

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Denny's Evil Concoctions said:
Sigh.. It's the temperature of the Refractometer NOT the wort. That drop of wort is not going to put a dent in the refractometer temperature, so you calibrate based on the ambient temperature, as long as the refractometer has been in the same enviroment to match the ambient air temperature. (unlike a hydrometer)

And for the record. If you Properly calibrate A: your refractometer, B: your software, you will get an accurate reading on fermenting and fermented beer.
Which of course, now begs the questions;
1) What is the best way to calibrate the Refractometer?
2) What do I need to calibrate inside of BeerSmith to make it correct???
 

Beerthoven

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Bearcat Brewmeister said:
Why let a hydro sample cool? Don't you just correct the reading for temperature?
Yes, but the closer the sample is to 60º (the calibration temp of my hydrometer) the more accurate the correction. I would not trust a hydro reading at, say, 150º.
 

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