Refractometer advice

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

spoonyluv

Supporting Member
HBT Supporter
Joined
Mar 28, 2011
Messages
89
Reaction score
6
Location
San Francisco
I'm hoping someone here can help with a suggestion. I'm using a refractometer from BobbyM and I'm finding that the reading for my fermented beer is very different from the reading with my hydrometer (and yes I did use the correction formula).

For example, a recent batch reads an FG of 1.010 with a hydrometer but reads 6 brix, which based on the OG of 1.057 is 1.003. That is a big variance and I'm trying to understand it.

As background, the refractometer is calibrated using distilled water and it matched the hydrometer reading for the OG.

Thanks in advance for any tips.
 
spoonyluv said:
I'm hoping someone here can help with a suggestion. I'm using a refractometer from BobbyM and I'm finding that the reading for my fermented beer is very different from the reading with my hydrometer (and yes I did use the correction formula).

For example, a recent batch reads an FG of 1.010 with a hydrometer but reads 6 brix, which based on the OG of 1.057 is 1.003. That is a big variance and I'm trying to understand it.

As background, the refractometer is calibrated using distilled water and it matched the hydrometer reading for the OG.

Thanks in advance for any tips.
Was the hydrometer temp calibrated?
 
You took your OG with both the hydrometer and refractometer and they agreed. You are at or near the end of ferment and now you have a difference. You've calibrated so every thing you have done is spot on. I would expect a reading of 1.010 to be closer to the truth unless you had a 94% attenuation to get to 1.003. Hmm... I hate to even suggest this but is it possible you read 6 on the scale and it was really a 7? a 7 Brix would be a FG of 1.010 SG
 
I never had this problem, and I use cheap e-bay refractometer.

I got nothing wise to suggest since refractometer is calibrated and it matches w/hydrometer OG reading. I would contact the seller and try to solve it with him, maybe he had similar complaints..
 
Thanks everyone for the feedback.

The readings are all taken at a room temp of 65 degrees so the variation on the hydrometer would be tiny.

A misread would be convenient but this has happened with several batches. In fact, I had broken my hydrometer and was using exclusively the refractometer but after several batches with a <1.005 FG, I bought a new hydrometer because the readings were suspicious to me.

I have emailed the seller and will see if I get any additional ideas.
 
I think I read somewhere that once alcohol becomes introduced through the fermentation, your brix reading needs adjustment calculations. I only use my refractometer when reading my wort, and then with my hydrometer during and after fermentation... :mug:
 
Grilla is correct, the ref meter reading needs to be adjusted to correctly read final gravity. There is a formula for it, just do a search for it
 
It appears he is using the formula to correct for fermentation. I have the same refractometer from Bobby and I will compare mine to a hydrometer and see what I come up with. Currently I only use a hydrometer after fermentation.
 
I received one of Bobby-M's refractometers as a gift this Christmas. I've used it for five brews since, comparing its readings against my trusty hydrometer, and the two have been within one SG point every time, whether testing pre-boil, post-boil/into the primary, and eventually post-fermentation/into the keg.

But I can only use the refractometer Brix scale, because the SG scale on my refractometer is quite wrong, especially as the wort density increases. A bit of a disappointment, but not a game killer, as there are plenty of programs out there that will give the correct SG from Brix (I use BS2)...

Cheers!
 
I'm hoping someone here can help with a suggestion. I'm using a refractometer from BobbyM and I'm finding that the reading for my fermented beer is very different from the reading with my hydrometer (and yes I did use the correction formula).

For example, a recent batch reads an FG of 1.010 with a hydrometer but reads 6 brix, which based on the OG of 1.057 is 1.003. That is a big variance and I'm trying to understand it.

As background, the refractometer is calibrated using distilled water and it matched the hydrometer reading for the OG.

Thanks in advance for any tips.

If the refractometer was dropped it may be off calibration. Purchase a standard solution and verify it is calibrated.
 
Temperature and calibration are extremely important with refractometers. I've used one for years on my saltwater aquarium and recently ditched it due to issues with the auto-temp correction feature.

You have to make sure that your calibration solution and the solution you are measuring are nearly the same temperature.

It's also important to use a calibration solution that is near the SG that you're actually testing for. So for brewing distilled water might be OK. For the aquarium I had to use a 1.0265 solution because that's what I test for in salt water. If I had calibrated with distilled, my aquarium would be in deep trouble!

In order to get a correct reading, I had to float my calibration solution in the aquarium water for 30 minutes, then calibrate.

It's also important to note, auto-temperature correct screws up if you're not at room temperature, make sure you're operation in 71 degree environment if yours has an auto-correct feature!!

For what it's worth, I now use a conductivity meter for the aquarium, I still need to test this on wort. It's way less hassle and less opportunities for error.
 
Back
Top