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Old 12-25-2008, 08:17 AM   #1
GNBrews
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Default Refractometer problems

Let me preface this post by saying I'm a total newb at using my new refractometer.

My problem is that when measuring liquids that have any color other than water clear (eg. beer and wine), my refractometer (with ATC) is reading *much* higher than my hydrometer.

For instance, when I measure the gravity of a batch of Welch's wine I've been fermenting, my hydrometer reads 1.010. However, when I place a few drops on the refractometer, it measures 10.2% brix (1.041). Measuring the gravity of a batch of Apfelwein that's finished, my hydrometer reads 1.000. The refractometer reads 5.4% brix (1.021).

I played around with creating plain sugar water solutions, and the hydrometer and the refractometer definitely jive when measuring those.

Sugar water experiments:

Hydrometer Refractometer
1.013 3.2
1.025 6.0
1.052 13.0

What am I doing wrong?


EDIT: Nevermind, as I said I'm a total refractometer newb. Read more...duh. I didn't realize that you need to use some fancy algorithms to calculate the gravity once there is alcohol in solution. Guess this thing is useful only as a pre-fermentation measure.

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Old 12-26-2008, 05:15 AM   #2
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refractometer is thrown off if there is alcohol in the sample as well as by chunks or sediment. You need to make sure its a clean sample your using for comparison. Also make sure your hydrometer reads 1.000 at 60 degrees F or whatever its calibrated at. Calibrate the refractomter the same way. They should agree for the most part. ahh i just read your edit. good catch

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Old 12-26-2008, 12:09 PM   #3
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Quote:
Originally Posted by GNBrews View Post
Let me preface this post by saying I'm a total newb at using my new refractometer.

My problem is that when measuring liquids that have any color other than water clear (eg. beer and wine), my refractometer (with ATC) is reading *much* higher than my hydrometer.

For instance, when I measure the gravity of a batch of Welch's wine I've been fermenting, my hydrometer reads 1.010. However, when I place a few drops on the refractometer, it measures 10.2% brix (1.041). Measuring the gravity of a batch of Apfelwein that's finished, my hydrometer reads 1.000. The refractometer reads 5.4% brix (1.021).

I played around with creating plain sugar water solutions, and the hydrometer and the refractometer definitely jive when measuring those.

Sugar water experiments:

Hydrometer Refractometer
1.013 3.2
1.025 6.0
1.052 13.0

What am I doing wrong?


EDIT: Nevermind, as I said I'm a total refractometer newb. Read more...duh. I didn't realize that you need to use some fancy algorithms to calculate the gravity once there is alcohol in solution. Guess this thing is useful only as a pre-fermentation measure.

Actually that's not true. You DO need to know what the OG was though. You'll enter the OG and current refract reading in brix into this spreadsheet http://morebeer.com/public/beer/refractbeer.xls
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Old 12-27-2008, 12:43 AM   #4
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That spreadsheet makes a fairly ideal attenuation assumption for your yeast. Still fairly useless during fermentation IMO.

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Old 12-29-2008, 04:12 AM   #5
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Is there anyway to do the brix conversion with alcohol within beersmith?

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Old 12-29-2008, 04:45 AM   #6
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Yeah, but I don't think it's accurate. Go to Tools, then "Refractometer Tool". Change the calculation drop-down to "Fermenting Wort Gravity", and fill-in both your current refractometer reading, and the starting specific gravity. The corrected specific gravity should be listed below.

Here's why I don't think it's accurate. If I put in my starting gravity as 1.103 for my Welch's wine, then enter the current refractometer reading of 10.2% Brix, it tells me that my gravity corrected gravity is 1.003. Measured with a hydrometer, it reads 1.010.

Same thing with the Apfelwein. My original gravity was 1.068 and my current refractometer reading is 5.4% Brix. The "Corrected Gravity" is 0.993. The gravity measures 1.000 with my hydrometer.

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Old 12-29-2008, 12:04 PM   #7
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I know there is some calibration options in the menus.. but don;t know to what extent..

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Old 12-30-2008, 03:14 AM   #8
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I'll buy the thing from ya at a discount if it's still giving you trouble.

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Old 12-30-2008, 03:26 AM   #9
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Thanks for the offer, dick.

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