Inconsistency between refractor and hydrometer

I have been having some inconsistent readings between my hydrometer and my refractor. I tested the two using some distilled water. Both read 0 with the distilled water. On the next brew day I got a gravity reading of 1.060 from the refractor and 1.07 with the hydrometer. Target OG = 1.065.

Last night I racked to secondary and measured the gravity.

Hydrometer 1.025
Refractor 1.040

I am frustrated by these inconsistencies.

Any suggestions?

thanks,
Adam

Hydrometer 1.025
Refractor 1.040

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Refractometer readings need to be corrected for fermented beer. The raw reading will always be way off.

more beer has an excel spreadsheet to correct this. find it here: http://morebeer.com/public/beer/refractbeer.xls

david_42 said:

Refractometer readings need to be corrected for fermented beer. The raw reading will always be way off.

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and just to add... while refractometers are auto temp calibrating...thats only to about +/- 20 degrees F.

So a really hot sample from the mashtun isn't going to be accurate. let it cool down, then take a reading.

malkore said:

and just to add... while refractometers are auto temp calibrating...thats only to about +/- 20 degrees F.

So a really hot sample from the mashtun isn't going to be accurate. let it cool down, then take a reading.

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This isn't correct. You need not cool the sample. The ATC feature (if equipped) compensates for the temperature of the instrument, not the sample. This is a common misconception for some reason. You will, however, need to correct for the temperature of a sample measured with a hydrometer. Maybe that's where the confusion originates. Not all refractometers have the ATC feature and for those there is a correction table.

OK, I'm a bit confused here. I don't believe my refractometer is giving me brix back as the scale on the device seems to be the S.G. not brix. I think that excel sheet is considering brix? I am not sure if this has ATC the manual with it is poor at best. Model on the box is RHBW-1.10

I think the 1-2 drops of wort you use would cool faster than you would ever have to worry about.

Regardless of the automatic temperature correction, I have noticed the gravity will change as the sample cools. I put the wort on the prism, lower the flap, and then let it sit for a few minutes before taking the reading. My refractometer measures in Brix so I use this to convert: Fermsoft - Winemaking and Brewing Software

Your hydrometer will be off if you are not measuring at the temperature it is calibrated to work out which is going to be either 60 or 68 degrees...should say on the paper it came with. (I have purchased two and both were 60). Then you need to correct it for the temperature of the wort/beer you are measuring: The Beer Recipator - Hydrometer Correction

Now you will have your two numbers and your refractometer should measure higher than your hydrometer. This is because your sample of wort has more than just sucrose in it which is what the refractometer was made to read. It usually reads 4-6% high so you need to divide your gravity from the refractometer by 1.05 or so to correct. You can determine your correction factor my using both instruments for a few brews.

Lastly, once you have alcohol in the same things get crazy and you have to do some more complex conversions. The morebeer spreadsheet will work just fine for you. If your refractometer is giving you a specific gravity reading just convert it to Brix: Brix = (SG-1)/0.004 or .01 gravity for every 1 point Brix (then you add 1 at the end). Then you can use that spreadsheet to determine the gravity, I have found it to be very accurate.

jspence1 said:

I think the 1-2 drops of wort you use would cool faster than you would ever have to worry about.

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+5 Bingo! You have it right.

Oh yeah, one more thing...read this!

Refractometer - Home Brewing Wiki

Catt22 said:

+5 Bingo! You have it right.

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I can't speak for all refractometers, but mine would disagree.

I concur with steelerguy - I have seen the ATC refractometer change readings with major temp shifts. I let it cool for about a minute on the dish before I take the sample. I suppose YMMV...

Yes, whatever works for you guys is fine with me, although cooling in a dish is likely to result in significant evaporation of a hot sample which will surely alter the sg reading. I don't know if it would be a measurable difference though.

aredling said:

OK, I'm a bit confused here. I don't believe my refractometer is giving me brix back as the scale on the device seems to be the S.G. not brix. I think that excel sheet is considering brix? I am not sure if this has ATC the manual with it is poor at best. Model on the box is RHBW-1.10

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I can't find that specific model, but I wonder if maybe you have a salt water refractometer and not a brix refractometer.

You definitely need to give a refractometer about 30 seconds to a minute to come to room temperature. I usually see an increase of about .5P over that time.