Has anyone had this refractometer problem?!

[finsfan]

So I got a used refractometer off of ebay for a great price. Here is a spec sheet of it. Its the Extech RF15

http://www.extech.com/instruments/resources/manuals/RF10_15_UM.pdf

this thing is in perfect condition and looks new. The first thing I did yesterday was take a reading of my tap water. It was perfectly calibrated and came out zero brix. I then went to take a reading of my fermenting IPA. It showed 7 brix which is way too high. I took a hydrometer reading the day or two before and the SG was 1.014 and now its 1.027? Im confused.

I was just reading the spec sheet above and it suggests to let the sample sit for 30 seconds before reading. Could this be the problem? Has anyone else had a similar experience? Do refractometers not work on fermenting beer? Any advice is helpful, thanks!

 

[B2Barleywine]

No, refractometers don't work once fermentation has begun. There are spreadsheets to correct, but many have mixed results and rely on hydro post fermentation

 

[finsfan]

damn, I thought I had read that somewhere once but I wasnt sure. half the reason I wanted it was so I didnt have to keep using a lot of beer (compared to refractometer) to get a gravity reading

 

[funnycreature]

This has been pretty accurate for me:
http://www.onebeer.net/refractometer.shtml

 

[LandoLincoln]

You should calibrate with distilled water as well. Your tap water might throw it off a tiny bit.

Refractometers are great for taking SG prior to fermentation, so it's not a bad investment.

 

[finsfan]

Thanks for the help. I may have to do some tests to see how closely the calculators can get the SG compared to a hydrometer.

 

[logan3825]

You can still use it to monitor fermentation. It will not give an accurate reading but should tell you whether your beer is still fermenting.

Also check out some of the refractomoter calculators.

 

[finsfan]

I did notice that last night it showed 7.5 brix and this morning was 7, still chugging along

 

[seph]

To prevent having to fill your test vial with beer every time you want to take a hydro reading, just sanitize your hydrometer, and drop it in the bucket....that's what I do. But if you are using car boys...you're SOL.

 

[Shooter]

I just use the refractometer and make the adjustment. My FG is almost always reading within a point of the predicted FG for the batch.

 

[goffx087]

damn, I thought I had read that somewhere once but I wasnt sure. half the reason I wanted it was so I didnt have to keep using a lot of beer (compared to refractometer) to get a gravity reading

A trick I use is adding a sanitized hydrometer right into the fermentation vessel. If you do primary in a glass carboy like me, you can check on the gravity in real time without exposure to oxygen/contaminants.

One issue I've had is yeast/trub clinging to the hydrometer tip after krausen, it makes it difficult to read sometimes and might actually contribute to a gain or loss of buoyancy. But all in all it works nicely for monitoring the progress of fermentation.