# Refractometer Calibration



## Drez (Sep 16, 2010)

If I'm unsure of my refractometer reading (i.e. if its accurate or not) is any further calibration needed other than zeroing to RO/DI (pure) water?

Thanks


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## djrockinsteve (Sep 16, 2010)

Drez said:


> If I'm unsure of my refractometer reading (i.e. if its accurate or not) is any further calibration needed other than zeroing to RO/DI (pure) water?
> 
> Thanks



There are some on here who have these, they can answer your question probably this evening. Hang in there.


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## Drez (Sep 16, 2010)

Thanks. I'm also in the Salt Water aquarium hobby where there is also the choice btw hydrometer and refractometer and the later is the clear winner in that case. Figured it made sense here too, I guess its less common then?


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## grapeman (Sep 17, 2010)

I find the use of a refractometer indispensible. Other than zeroing it, there really is no other adjustment. Since it relies on bent light (which hopefully does not change), there is no need to calibrate it other than to zero. I have had mine for years and have yet to need to adjust. If you want to verify it's accuracy, use your hydrometer and test cylinder to verify it. Use some sugar water in the range you suspect. Take a hydrometer reading on a triple scale. If you get 1.080, look that up on the scale for brix. Take a refractometer reading and they should be the same. I feel the refractometer is way more accurate, especially if it is temperature compensating- which the hydrometers aren't.


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## Dugger (Sep 17, 2010)

I used one of these for the first time about a month ago at a friend's house - his daughter had given it to him and he had no idea what to do with it; well, neither did I, but having read about it on here and with the directions, we figured it out and were taking Brix readings on everything - like kids with a new toy ( that's what our wives thought, for sure)!
So, to use one of these for tracking fermentation, do you just take readings regularly, like with a hydrometer, and when the Brix doesn't change over 2-3 days you know the ferment is done? If that's the case, this seems a lot easier than cleaning, sanitizing, storing, breaking, replacing hydrometers, test jars, etc. - just put a drop on the refractometer and you're good to go!
Sounds too easy.


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## Drez (Sep 17, 2010)

> Grapeman



Grapeman, thanks so much that what I was looking for. I figured that was the case but wanted to make sure as its one of the more important tools in this hobby, we base some fairly important decisions on these reading. I didn't actually get a hydrometer as I didn't want both tools but I might double check it at the wine place or w/ a friend just for verification.

Thanks for the help. 



> Dugger



Exactly they're lovely for that exact reason, just take a tiny drop, peak through and there you have it. In aquariums prevents dripping salt water everywhere, tapping to getting bubbles out, errors due to salt built up, cleaning and all that fun stuff. I can only imagine it translates to the same benefits in this hobby. 

Like grapeman said too, I understand them to be more accurate as well. Bonus points.

My wine/beer refractometer is scaled with both SG and Brix so no need to convert, its normalized between 1.00 and 1.1 so I can't measure below 1.00 but thats a pretty safe end point in most cases I assume right?


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## Dugger (Sep 17, 2010)

That actually could be a bit limiting - I've had a wine go down to 0.992, so there can be quite a lot of movement below 1.000.
Are all refractomters scaled like this? I can't remember the scale on my friend's - it came from Lee Valley store.
Anyone??


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## jet (Sep 17, 2010)

IIRC, alcohol interferes with the refractometer readings, so it can't be used to measure brix once fermentation starts.


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## Dugger (Sep 17, 2010)

Ah, OK thanks, I thought it sounded too easy!! And now that you mention it, I seem to recall reading that. Darn.


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## Luc (Sep 17, 2010)

jet said:


> IIRC, alcohol interferes with the refractometer readings, so it can't be used to measure brix once fermentation starts.



Yes it can !!!

There is a spreadsheet around that adjusts the refractometer readings
for use when there is alcohol present.

There is a link to that spreadsheet and a complete story on the refractometer on my web-log. You can read it here:
http://wijnmaker.blogspot.com/2010/04/refractometer.html

Luc


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## Rock (Sep 17, 2010)

Refractometer has a small srew on the bottom of unit ,you use a drop of distilled water look thru the view and with a small srew driver you zero your unit in.


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## Drez (Sep 18, 2010)

Luc said:


> Yes it can !!!
> 
> There is a spreadsheet around that adjusts the refractometer readings
> for use when there is alcohol present.
> ...



Thanks for that link, I found that a helpful read.


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## Drez (Sep 29, 2010)

Can't stress enough how helpful this was, I thought my wine had stopped fermenting with 1.030 SG, this saved me from wasting time and effort on acclimatizing yeast etc. 

http://www.winemakingtalk.com/forum/showthread.php?t=9279&page=2

Assuming I were to use the same starting SG (i.e. I were to make the exact same Kit for example) I can now consider 1.030 SG to be my end point correct as it should always yield the same amount of alcohol for the same amount of error, correct?


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## xoltri (Sep 29, 2010)

Well, if you started at 21.5 brix that's 1.090. Then at the end if your brix is reading 7.5 with the spreadsheet calculation that is 0.994, so yes I'd say it's finished. And this calculation will always be the same so if you always start at 1.090 then 7.5 brix FG will always be 0.994. 

But if it's ever not exactly the same just use the spreadsheet, it's easy!


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