Beersmith & refractometer users, what's your brix correction factor?

I just got my refractometer, and once I have a brew day I'll be able to do the wort calibration, but I'd like to use it on some finished beers so I decided to calibrate it now. I got the distilled water and set the zero. My refractometer has ATC.

To get the brix correction factor I made a solution of distilled water and table sugar. The hydrometer measured it at 1.032 (70F) corrected to 1.033 (60F) and the refractometer came in at 7.7.

Entering this into beersmith gives me a brix correction factor of 0.9306.

I don't have any problem with that, sounds good, but then I pulled a sample of my kegged cream ale. I let it come to room temp and let the CO2 come out of solution. Hydrometer read it at 1.009 and the refractometer at 4.2. That gives me a calculated OG of 1.030. I am notoriously lax on my OG reading, but I thought it was more up at 1.044. That would be an all-time low efficiency (50%) by about 20%. That just doesn't seem right.

bump. Anyone who has an optical refractometer and beersmith can help me out here.

edit: It just occurred to me that I can test a few of my other beers that have better OG readings. I'll do that in the mean time.

err...pumpkin ale: FG 1.020 refractometer: 7.5 --> OG: 1.045

This one measured 1.066. Also, messing with the wort calibration values doesn't seem to change the calculated OG value. What's going on here?

All that I can do to help is a bump. Sorry.

I'm not sure this will help since I've never used my refractometer post-fermentation. When I first got it I entered my calibration data in beersmith and my correction factor is 1.0317.

Not sure if this will help at all. I suspect if you had some DME laying around you could mix it up and measure it with your hydrometer and refractometer to come up with the numbers

I don't, but I'm really surprised that the calibration isn't changing the post-fermentation values.

How do you know your hydrometer is correct? That could explain why you are off so far. Based on a previous thread I tested all my hydrometers with distilled water at 60F and found that one was reading high by 6 and another by 4!

I am having the same problem.

Although the zero is correctly calibrated on my new refractometer, the % Brix scale does not match hydrometer readings above zero. For example, a solution that reads 7.25% brix in the refractometer (which is equivalent to 1.029 gravity) has a hydrometer reading of 1.010. I can tell by taste that the residual sugar content is not as high as 1.029. Has anyone tested their refractometer against a hydrometer for solutions above zero? Am i missing something?

Thanks for the help.

I dont have a refractometer, but it is my understanding they can only be used before fermentation. The presence of alcohol changes the refractometer reading. There is a way to correct for it but the calculation is different.

Mine averages 1.0276 across four batches. It's only relevant for pre-fermentation readings - it adjusts for the non-sugars in your wort, not the ethanol in fermented beer. Beersmith can estimate post-fermentation refract readings, but the Brix correction factor doesn't have anything to do with that.

Bump...

Correction factor is needed yes, mine is 1.054. This accounts for the OTHER junk in the wort that is NOT sugar that is affecting the refraction of light.

Refracts CAN be used to very accurately measure the FG, BUT you have to have the OG in terms of BRIX or Plato to do so.

If you are using a brewing software application and you input the OG in Brix anyhow, when it is finished fermenting just plug in the FG in Brix and it will give you an accurate reading since the software will compensate for alcohol.

If you go with the "standard" 1.040 correction and your's is actually 1.054 (like in Pol's case) How much is that actually throwing off your readings? Anything to be worried about? I bought anew refractometer ISNTEAD of a new hydrometer. Don't wanna buy a Hydrometer. Brew money is very tight, I'd rather spend the $15 of a hydro on ingredients.

bump......

I thought the correction factor was different for every batch. At least, in my experience measuring brix refractometer vs hydrometer this has been the case.

I have found that even a slight amount of bubbles and visible solids on the refractometer lens cause abberations in the readings.

Like a few others have said, the refractometer readings of fermented beer do not give a direct translation to gravity.

See http://byo.com/component/resource/article/1343-refractometers for details of the math. I never tried applying these formulas, but I did try the Promash calculator which was fairly accurate for lighter beers (O.G. < 1.050), but got progressively more inaccurate as the OG increased.

-a.

This refractometer if proving to be not as cool as I originally thought when I bought it. I'll keep at it. It seems you need a few brews worth of readings to get a good calibration.

I have a mild now that had a OG of 1041(hydro) brix12(refract)
Now my brix is 7
I believe (with what I've done in beersmith) that my SG is currently at 1029. I just brewed this Saturday so it's very plausible it's still fermenting. There was a kraussen ring when I took the reading but noticed more foam than about 1 hour prior when I has taken a sneak peak. I'm thinking it got cold and is kicking back up. I'll check again Friday. At least with the Refract I'll be able to see if the brix is consistent for a few days then take a hydrometer reading for final FG, saving the test samples for the consecutive readings.
It looks like Promash may be a little more Refractometer friendly.

I just got a refractometer for Xmas and am having some major confusions with it as well... It was certainly great today while brewing to be able to take quick readings without having to cool the sample, however I certainly got confused when I read a sample that is still in primary (has been in for 10 days, getting ready to rack to secondary) and it read 7.9 brix but my hydrometer read 1.010. Unfortunately I do not have an initial brix reading because I brewed it before I got this refract. I used the 3rd formula from here, and when I enter the hydro reading and refract reading, it is exactly spot on in saying that the OG was 1.066. Guess I'll have to play with this thing some more.

Sorry if this confusion has been answered, but like Pol was saying, you need to know the og and the current brix to correct for the amount of alcohol in the sample while the beer is fermenting.

For example:

IrregularPulse said:

I have a mild now that had a OG of 1041(hydro) brix12(refract)
Now my brix is 7

Click to expand...

When you place this data into beersmith's refractometer tool you need to choose whether it is unfermented or fermenting. Without changing the drop down tab, you the program does not know that you have begun fermentation.