[majorvices]

So, using the hydrometer correction calculator found here: http://www.onebeer.net/refractometer.shtml gives me incorrect results. For instance, when I type in my original brix (12) and my final brix (5) the reading says says my final gravity is 1.002 .... however, the OG was ~1.050 and the FG is around 1.012 according my correctly calibrated hydromter (the refractometer is also correctly calibrated) ... so what's going on? Is that calculator off or WTF?

[tom]

What was the final gravity reading of the refractometer?

[a10t2]

In my experience, the correlation becomes less reliable the further you get from "normal" gravity and attenuation. At 1.050 and 76%, I don't think that's your problem though. I think high concentrations of dissolved gases also throw off the refractive index, so if fermentation is active that could be a factor. It tends to RAISE the Brix reading though, IME. 5°Bx is very low.

[a10t2]

What was the final gravity reading of the refractometer?

my original brix (12) and my final brix (5)

[tom]

Just checking!

ProMash gives the same results.

[majorvices]

could it simply be yeast in suspension skewing the results? Its fairly cloudy and, come to think of it, my IPA was pretty cloudy too and I got the wrong result.

[a10t2]

Suspended solids shouldn't have any impact on the RI. A cloudy sample makes it hard to read the line accurately. I don't think you could get a ~2°Bx discrepancy from that though.

Things like this are why I went back to using a hydrometer for all FG readings.

[blatz]

see, its odd, my refracto is always spot on (after correction) with the hydro sample (I still take the hydro on occasion cause I like to taste how things are coming along  )

Don't know what to tell you 

[a10t2]

Hey blatz, I've been doing both to try to get some data points. Once I have 10 or so I'll let you know and hopefully we can compare notes.

[weazletoe]

Here's what you need to do Major. You have a pickup truck, right? (if not you can borrow mine) Take your refracto, and drive over it several times with your truck. Once I did this with mine, and went back to my hydrometer, I had no more issues with it. 

[denny]

BRILLIANT!

[Thirsty_Monk]

Back to basic!!! 

[blatz]

I can't understand how you guys can't get a simple tool to work.

I've helped 2 other guys in my club acquire a refracto, set them up with the correction formulae and they are fine.

There is a thing called 'user error' 

[bluesman]

We call it "operator error".    Just kidding.

I like to use my refractometer during the mash and pre-fermentation because it's quick and easy. However, I always use my hydrometer post fermentation because it's most accurate and reliable at that point in the process.

I haven't had any success using a refractometer post fermentation as you are also experiencing. Maybe there's something we are missing, but I like to use my hydrometer because it's dual purpose. I can quantify the result by measuring the gravity and qualify the result by tasting the beer from the hydrometer tube. 

[rabid_dingo]

Another

Here's what you need to do Major. You have a pickup truck, right? (if not you can borrow mine) Take your refracto, and drive over it several times with your truck. Once I did this with mine, and went back to my hydrometer, I had no more issues with it. 

Oh Snap! I really did laugh out loud...