Question on reading a refractometer

[BigdogMark]

I have a new refractometer I have been using for a while with favorable results, particularly when comparing to hydrometer readings. But I took a reading this afternoon that was unlike all others and I was wondering why. I have a Golden Strong Belgian that I started last Sunday. It came in low on the OG, and we are working on figuring out why, but the brix reading (18.0) and the hydrometer (1.071) agreed on the OG within .001. The line in the refractometer was very clean and distinct, very easy to read.

Today I took reading on the fermenting wort to get an idea of where it is. I know there are corrections to be applied and all that, but the question I have is regarding the clarity of the line in the refractometer. It was very fuzzy, between 9 and 10 brix. Now the beer is still actively fermenting, sure. But does the yeast in suspension significantly affect the refractometer?

My intent is to use the refractometer to determine when it is through fermenting, and take a final reading with the hydrometer when transferring the beer.

 

[JayMac]

Never use a refractometer once yeast has been pitched. Some have reported accurate results using correlations, but the stories I've heard about improper readings indicate that you might as well just use your hydrometer and thief.

If you don't trust it 100% of the time when taking FG readings, why use it at all?

I use mine only for SG of runnings, various boil SG, and the OG. After that I put it away until I brew next.

Cheers

 

[luhrks]

Yeast isn't a sugar. Refractometers measure diluted sugar, not yeast. Worse - they shadow. Ergo, you will not get a clear reading.