Refractometer vs. Hydrometer Video

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

Help Support Homebrew Talk:

cactusgarrett

Well-Known Member
Joined
Apr 8, 2008
Messages
2,119
Reaction score
732
Location
Madison, WI
This may be a pretty elementary question, but i'm new to using a refract: For pre-fermented wort, once i get the OG, Brix and subsequent correction factor, is this factor constant across every pre-fermented liquid i test, or does the factor apply only to this batch of wort throughout its fermenting life?
 

cactusgarrett

Well-Known Member
Joined
Apr 8, 2008
Messages
2,119
Reaction score
732
Location
Madison, WI
I mean the correction factor. I ask because the tab in the options menu in Beersmith for "Calibrate Refractometer Settings" (step 2) saves these inputs.

So, being unfamiliar with the refractometer section in Beersmith as well as the refractometer itself, i'm going to have to "calibrate" this Beersmith setting and get a correction factor for each wort?
 

ArcaneXor

Well-Known Member
Joined
Nov 10, 2007
Messages
4,502
Reaction score
127
I mean the correction factor. I ask because the tab in the options menu in Beersmith for "Calibrate Refractometer Settings" (step 2) saves these inputs.

So, being unfamiliar with the refractometer section in Beersmith as well as the refractometer itself, i'm going to have to "calibrate" this Beersmith setting and get a correction factor for each wort?
1.04 is a pretty standard correction factor. What it does it account for the fact that beer isn't just made out of water and sugar, but that there are other components as well that refractometers aren't designed to take into account.

From BYO:

Understanding the Reading

If a sample is simply sucrose and water, you can take a refractometer reading directly. If, however, you are testing wort, which is mostly maltose, you must make a correction that I call wort calibration.

Wort Calibration

Measurements of the specific gravity of wort using a refractometer will not agree with the measurements of gravity using a hydrometer. Brix refractometers are meant to measure the percentage of sugar in a pure sucrose solution. Since wort is not simply sugar and water, you need to make a small correction because of the non-sugar components of the wort. The correction factor is different for different breweries. Beers that are very dark or have a very high starting gravity may also require a different correction factor. To calculate your correction value, measure the specific gravity with your refractometer. Then chill a sample of your wort and measure the gravity with a hydrometer. Convert the hydrometer reading to Brix using the equation: Brix = (SG-1)/0.004. Then divide the reading of the refractometer by your actual hydrometer reading. You should have a number between 1.02 and 1.06. If you do this for several worts and average them, you will get a number that you can use for your brewery. ProMash defaults to 1.04 and this is the number I use. Once you have this number, divide all of your subsequent refractometer readings by your calibration number to get the actual reading. For example, if your reading is 14.6 Brix then your corrected reading is 14.04 Brix (14.6/1.04=14.04). Then, we can convert the measurement in Brix to specific gravity.
 

cactusgarrett

Well-Known Member
Joined
Apr 8, 2008
Messages
2,119
Reaction score
732
Location
Madison, WI
If you do this for several worts and average them, you will get a number that you can use for your brewery.
Cool. Thanks for the details - this is specifically what i'm looking for. I was testing out a starter i just made, and came up with a correction of 1.0757 from an OG of 1.033 and 8.9% Brix. I plan on testing each wort from here on out with grav AND Brix to make sure they jibe, but by you mentioning to average serveral worts, this leads me to believe that the correction factor i get resulting from grav to Brix is characteristic of my specific refractometer. Does this seem like an accurate statement?
 

ArcaneXor

Well-Known Member
Joined
Nov 10, 2007
Messages
4,502
Reaction score
127
Cool. Thanks for the details - this is specifically what i'm looking for. I was testing out a starter i just made, and came up with a correction of 1.0757 from an OG of 1.033 and 8.9% Brix. I plan on testing each wort from here on out with grav AND Brix to make sure they jibe, but by you mentioning to average serveral worts, this leads me to believe that the correction factor i get resulting from grav to Brix is characteristic of my specific refractometer. Does this seem like an accurate statement?
I think it's more characteristic of the types of beers you tend to brew, and the averaging procedure also accounts for user-induced error from inconsistent hydrometer readings.
I am not sure, but I would think that the calibration value would be constant between refractometers.

I'll probably be able to comment on this more once I actually receive my own refractometer sometime in the next couple of weeks :)
 
Joined
Dec 16, 2007
Messages
47
Reaction score
2
Location
Indianapolis
I think it's more characteristic of the types of beers you tend to brew, and the averaging procedure also accounts for user-induced error from inconsistent hydrometer readings.
I am not sure, but I would think that the calibration value would be constant between refractometers.

I'll probably be able to comment on this more once I actually receive my own refractometer sometime in the next couple of weeks :)
probably not a big deal, but i believe the primary intention with this experiment is to calibrate your new refractometer response to your hydrometer (calibration errors with your hydrometer, calibration errors with refractometer, systematic error in the manner in which you interpret hydrometer readings, etc) while taking into account your brewery (typical beer styles you brew, contributions from your equipment, etc). this offset, or "factor", will likely change from refractometer to refractometer (inter and intra model) as no two instruments are ever identical…you’ll probably also find the factor will change if you bring in a new hydrometer into your shop (they’re not all identical either). it’s a good idea to do this once when you get your new refractometer to establish your factor…then periodically verify your factor to account for any drift (bouncing your refractometer on the floor the day after you’ve established your factor may warrant a “verification”, e.g.).

I use an ATAGO PAL-1 model refractometer (given to me) and have been pretty happy with the performance.
 

ArcaneXor

Well-Known Member
Joined
Nov 10, 2007
Messages
4,502
Reaction score
127
OK, got mine today and checked it on my pseudo-Apfelwein OG. It's the RHWN-25/BrixATC:

First sample:

Calibrated Hydrometer after temp correction: 1.057
Calibrated ATC Refractometer: 13.8 Brix

Second sample:

Calibrated Hydrometer after temp correction: 1.059
Calibrated ATC Refractometer: 14.0 Brix

Nearly spot-on!

What is interesting, though, is that Strangebrew Java, the Morebeer spreadsheet and various internet calculators to convert Brix to OG vary by as much as 3 gravity points. Very interesting.
 

nathan

Well-Known Member
Joined
Apr 8, 2008
Messages
945
Reaction score
10
Location
NC
I found that my brix reading was off, based on a table I found online for converting brix to specific gravity. Then later I tested my (3rd) hydrometer, and found it was 2 points off in proper temperature distilled water (read 1.002). So now I need to consider getting my FOURTH hydrometer.

My first broke, no surprise there. My second got less accurate over time, till it was 6-7 points off. This one is now 2 points off. It's not points low, which might be explained by hitting the bottom of tubes or something when it's slid into it's case, I cannot explain why the paper inside is somehow riding UP in two hydrometers.

Does anyone sell a stainless hydrometer with gradations etched on it?

I'd like to test my refractometer against an accurate hydrometer for a few sessions before I'm comfortable enough to drop the hydrometer.
 

PseudoChef

Well-Known Member
Joined
Apr 18, 2007
Messages
3,401
Reaction score
117
Location
West Chicago 'Burbs
For any mathematically inclined, I believe this is the correction formula:

SG = 1.001843 - (0.002318474*OB) - (0.000007775*OB*OB) - (0.000000034*OB*OB*OB) + (0.00574*FB) + (0.00003344*FB*FB) + (0.000000086*FB*FB*FB)

SG = actual specific gravity
OB = original Brix
FB = final Brix
 

nathan

Well-Known Member
Joined
Apr 8, 2008
Messages
945
Reaction score
10
Location
NC
do they make refractometers that are plato? Or are plato and brix the same?
 

BeerCanuck

Well-Known Member
Joined
Sep 20, 2007
Messages
473
Reaction score
2
Location
St Catharines
Excellent Video Bobby..I am now convinced it's a needed device vs gadget.
I bought one off ebay
$24 for the refractometer and $20 for shipping...hope it arrives in one piece :)

Cheers
Steve
 

Munsoned

Well-Known Member
Joined
Mar 23, 2009
Messages
642
Reaction score
1
Location
DC Metro
Just bumping this (awesome) thread to ask if anyone that recently bought a refractometer has any follow up they'd like to add--does it work, is it relatively accurate, etc.? Any particular models that are working/not working for folks?

Thanks!
 

ArcaneXor

Well-Known Member
Joined
Nov 10, 2007
Messages
4,502
Reaction score
127
I don't really use mine (RHWN-25/BrixATC) anymore, except for meads. Too much variance between successive readings due to small hop particles, trub, etc.
 
OP
Bobby_M

Bobby_M

Vendor and Brewer
HBT Sponsor
Joined
Aug 3, 2006
Messages
25,663
Reaction score
4,962
Location
Whitehouse Station
I always use mine during brewing and for taking the OG. I've given up on trying to use it for mid/FG because the correction spreadsheet always seems to be +/- 1.002. I guess if that's "good enough", it's still workable. I would be OK with it but I find that I always want to taste the sample anyway so I've found a smaller volume test tube and a smaller hydrometer so it only takes me 1 ounce. I get my accurate FG and a quick sip of beer.
 
OP
Bobby_M

Bobby_M

Vendor and Brewer
HBT Sponsor
Joined
Aug 3, 2006
Messages
25,663
Reaction score
4,962
Location
Whitehouse Station
I got a huge score of brewing materials from a guy on CL and I found it in a box. The tube is like 1/2" x 4" and the hydrometer fits inside. The scale is only 1.000 to 1.040 but I find that it's perfect for FG reading. I had to drill a hole in a block of wood to hold the tube upright because it's a curved glass bottom test tube. No big deal.
 

bull8042

I like 'em shaved
Lifetime Supporter
Joined
Jul 16, 2008
Messages
10,259
Reaction score
458
Location
Fort Mill
.....I've given up on trying to use it for mid/FG because the correction spreadsheet always seems to be +/- 1.002. I guess if that's "good enough", it's still workable....
I was about to bring this up. Bobby, I think it was from one of your posts that I downloaded the B3 spreadsheet. I just noticed last Saturday that the spreadsheet and BeerSmith don't agree on OG when converting from Brix.
I will have to look again, but I recall that there were several points difference calculating the OG of unfermented wort.
 

The Pol

Well-Known Member
Joined
Feb 12, 2007
Messages
11,390
Reaction score
117
I just found out today that my hydrometer is LOW by between 2 and 4 points... so I ordered an ATC refractometer. I use ProMash and it seems that the use of the refractometer for OG and FG will be pretty easy due to the fact that ProMash will do all the calculating for me as long as I tell it the OG Brix and FG BRix.

It actually converts it to Plato and SG and will compensate for the alcohol in the beer after the ferment. YAY!

For those of you using the refractometer, what correction do you use? 1.040? I hear that is typical.
 
Top