Refractometer and BeerSmith

[servadia]

Hello. I just got a Brix/SG Refractometer with ATC. I followed the setup/calibration steps included with the refractometer. I also followed the steps recommended by BeerSmith but cannot get the numbers to match up. Here is what I found so far:

Unfermented wort
Hydrometer (corrected for temp)= 1.077
Refractometer = 16.1 Brix

Wort that is finished fermenting
Hydrometer (corrected for temp) = 1.020
Refractometer = 5.1 Brix / 1.020

When entering all of this into BeerSmith, NOTHING is adding up. Suggestions???

 

[pompeiisneaks]

well, first off, something is not adding up on the orginal gravity. My app, Beer Alchemy for the mac, when you take an OG of 16.1 brix, gives 1.064 OG, not 1.077. This reading, on a refractometer should always match up perfectly. Its when alcohol is added post ferementation that it needs adjustment based on OG. This makes me think your hydrometer may be off? So, if I take that as a guess, my reading of the FG w/ that 1.064 as a starting gravity shows: For final reading of 5.1 brix, and OG of 1.064, the current Gravity is .994 that also seems pretty far off.. I'd almost suspect that you may want to re-calibrate the refractometer and the hydrometer at the right temps and do another test. The hydrometer data seems much more likely, but somethings definitely out of whack.

If you do the opposite assumption, then the OG of hydrometer, and FG of hydrometer are right, we can guess where the brix should be...

If the OG is 1.077, the OG brix should be: 20
If the FG is 1.020, then the FG brix would end up: 10.2 according to my app... (not beer smith again, but these numbers did jive well w/ MoreBeer's XLS sheet also on previous tests.

Sounds like maybe the refractometer is still off? Did you use distilled water and do the calibration at the temps it indicates? It is auto temperature correcting for the wort, but not for calibration. Same w/ hydrometer calibration, make sure you read the temps its supposed to be at, some are 69 others I've seen are 59... depends on the manufacturer I guess...

Edit: Had to fix a number, brix was 10.22 meant to be 10.2.

 

[servadia]

Thanks for the reply. I'm going to go back to the beginning and re-calibrate everything and start fresh.

PS. - What version of MoreBeer's xls are you using? I just downloaded it a few minutes ago and got some different numbers than you did. For example, when I enter 16.1 Brix, I get 1.066, not 1.064 as you did. And, when I enter 20 Brix, I got 1.083, not 1.077.
Just a head's up in case you're using an older version.
Northern Brewer has a similar tool that gave even different numbers! Let me know what you get with this one... http://www.northernbrewer.com/refractometer-calculator

Thanks again!

 

[pompeiisneaks]

Well I was indicating that my application was getting 'similar' numbers to their xls sheets... I.e. they weren't exactly the same but same ballpark. I did it just yesterday, (downloaded it that is). I've been reading up on refractometers and such harcore because I got on for xmas myself, and wanted to get data that matched too, mine did, but sounds like yours isn't. I checked on northern brewer and I get pretty close stats to what I saw on my tests w/ my OG, FG etc. This was one test w/ fg of a known og and fg from my hydrometer. I got 10 brix and had fg of 1.014 w/ og of 1.091. They were within .001 or .002 of the hydrometer. The xls sheet was also within .001 or so of the Beer Alchemy numbers I saw for that one... I've not played w/ the xls sheet on these stats at all... but sounds like you did.

 

[servadia]

Hey thanks again! I think starting from scratch will get me on the right track...now that I've done a ton of research as well. Do you find the MoreBeer or the NorthernBrewer calculations to be better?

 

[pompeiisneaks]

After a little playing, my forward and reverse were pretty close across the board, seems like NB is a little more off, but the morebeer and beer alchemy were right in line:

Starting Brix: MB: 20 brix = 1.083 OG. BA: 20 brix = 1.080, NB: 20 brix = 1.083
OG from FG and Brix: MB n/a BA: FG Brix, 10, SG, 1.014, OG=1.081, NB FG Brix = 10, sg 1.014, OG=1.078
FG from OG and Brix: MB n/a BA: OG, 1.083 current Brix: 10, FG 1.013, NB: Starting Brix, 20, ending brix 10, FG=1.013

All very close across the board, within .001 on all except one NB stat that seemed .003 thus why I said it was most off.. I hope that's all readable...

 

[servadia]

Yep...makes sense. How did you INITIALLY calibrate your refractometer? I used distilled water and adjusted the screw until I got "0"
Then, I boiled some sugar water and that is where things got weird...like the 1.077 hydrometer reading and 16.1 Brix. Should I have used actual wort instead?

 

[pompeiisneaks]

I know that my refractometer was indicating to calibrate at 68degF. My kitchen is almost always exactly that. (in the winter). I think that sugar water may be off because refractometers use light, and unless the sugar is not making a clear liquid(I.e. It's brown or tubinado) it may not affect the light like wort would, but I'm far away from smart enough to know that.

 

[enid]

To check your refractometer, calibrate first with distilled water to read zero. Then add 10gm sugar to 90gm warm water and dissolve. This mixture should give you a reading of 10 brix, approx 1.040 gravity. If it is off then it is your refractometer. If it is correct I would suspect your hydrometer.

Also below is a link to the best spreadsheet I have found for calculating FG. All other programs I have used (morebeer, beersmith, etc.) start to give inaccurate readings when attenuation starts getting close to the 80% mark.

http://seanterrill.com/2010/06/11/refractometer-estimates-of-final-gravity/

 

[ajf]

Yep...makes sense. How did you INITIALLY calibrate your refractometer? I used distilled water and adjusted the screw until I got "0"
Then, I boiled some sugar water and that is where things got weird...like the 1.077 hydrometer reading and 16.1 Brix. Should I have used actual wort instead?

You should have used actual wort to determine the wort calibration value.
Using Beersmith, select refractometer tool.
Select Calibrate Refractometer Settings, and follow the instructions. When they say "Take a sample of unfermented wort" is step 2, they mean take a sample of unfermented wort, not take a sample of sugar dissolved in water.
For a good explanation, download Promash, select Options, System Settings, Instrument Calibration, and then select help "?" to get a good explanation of the Brix correction factor.
Using sugar to determine the Brix correction factor will give you inaccurate readings.

-a.