Refractometer?

[MaxStout]

Looks like my cheap Amazon refractometer has the wrong conversion (assuming this calculator is correct). Here's a picture. 30 brix is supposed to be 1.129, but on my refractometer, it would read 1.117.

So which model did you buy? I am considering refractometers on Amazon, and might want to avoid that one if the two scales don't track.

 

[TyTanium]

The ebay one is coming from China. They say it's corrected but it's clearly the same as the old one. One of the sellers even has a link saying something like "if accuracy is important to you, check out the world's most accurate refractometer, the old incorrect scale has been corrected" selling for double the price. It's the exact same refractometer. Caveat emptor

 

[mtnagel]

So which model did you buy? I am considering refractometers on Amazon, and might want to avoid that one if the two scales don't track.

This one.

 

[MaxStout]

Damn...that's the one I had my eye on. At $30, I thought it might be too good to be true.

I suppose I could just ignore the OG scale, use Brix and convert it correctly. But the fact that those two scales diverge so much makes me wonder if one or both of them might not be calibrated properly.

Anyone have a recommendation for a good, sub-$50 refractometer?

 

[dk21]

Here's a link to a spreadsheet that will help determine your wort correction factor:

http://www.brewersfriend.com/how-to-determine-your-refractometers-wort-correction-factor/

 

[MaxStout]

Here's a link to a spreadsheet that will help determine your wort correction factor:

http://www.brewersfriend.com/how-to-determine-your-refractometers-wort-correction-factor/

That corrects the true Brix value versus the indicated value from the instrument. How does that correction account for differences indicated between the two scales?

 

[slaithe]

That corrects the true Brix value versus the indicated value from the instrument. How does that correction account for differences indicated between the two scales?

With maths... the sg value is a function of the brix value... if you have the correct brix value you can then determine the sg value by converting it. Kind of like ferinhight and celciuse... Or maybe you could think of it like inches or cm?

Well technically neither is function of the other, the function is just the equation that lets you figure out how much eros might be in us dollers (for example), but obviously one unit is not derived from the other... just difrent amounts of "value" per base unit...

 

[slaithe]

Depending on your scale, if you got a nice refractameter, you may be able to just look at the brix value and line it up... and I'm sure but there are probably lots of corrected charts out there if you don't...

The different apps calculators and web calcs throwing difforent values is kind of weird though. Has any one tried comparing them with the calibration settings/functions all set?

I really want one of theese things but their so so pricey... :-(

 

[mtnagel]

Looks like I'm going to have to test between my refractometer and hydrometer. I've already done it with DI water and I did it with beer once, but I don't remember how close the numbers were. I may just do it with sugar solutions so I don't have to waste beer

 

[MaxStout]

With maths... the sg value is a function of the brix value... if you have the correct brix value you can then determine the sg value by converting it. Kind of like ferinhight and celciuse... Or maybe you could think of it like inches or cm?

Well technically neither is function of the other, the function is just the equation that lets you figure out how much eros might be in us dollers (for example), but obviously one unit is not derived from the other... just difrent amounts of "value" per base unit...

I get the conversion between Brix and OG. My concern was not one of simple conversion between the two units; but rather, the fact that the scales did not track throughout its range. Using your analogy, it would be tantamount to a thermometer to show a correct correlation of, say, 0C/32F, but not line up 100C/212F.

In the case of the refractometer, it shows a correct alignment at 0 Brix/1.000 O.G., but the correlation diverges at higher gravities. As a previous poster noted, 30 Brix should be 1.129, but displayed as 1.117 on the refractometer. This seems to be a significant error in the scaling.

 

[hops2it]

I'm using the Brewzor app as well. Have you calibrated the refractometer calc in it? There is an option to calibrate in the drop down menu (in the refractometer calc) where you enter a Hydrometer reading then enter the refractometer reading and it will adjust the correction value accordingly.

Ran into a glitch. I calibrated my refractometer in distilled water to read 0. I then noticed my hydrometer reads 0.998 in the same distilled water. Evidently, Brewzor doesn't plan for the hydrometer reading LOW because when I input those two values, it doesn't seem to accept it.

I'm seriously thinking about this plan:
1.) Trust my brix scale reading on my calibrated refractometer entirely.
2.) In Brewzor, use the calibrate feature by entering known values from the adjustement tables such as the brewersfriend tool. So if I pick a reading toward the middle say...16 brix...in Brewzor I enter 16 brix and a SG of 1.0654.

Basically then, I end up making the Brewzor app match up with the online calculators and then I throw all my faith into my refractometer's brix reading for unfermented wort. In this event, even with high gravity situations, I should always get a gravity value that matches the adjustment tools while still using one app to do all my calcs.

Sound ok or flawed?

 

[mtnagel]

1.) Trust my brix scale reading on my calibrated refractometer entirely.

Do you have a scale? If so, you can check on the brix by making a solution with sugar. Add 30 gram sucrose to 70 g water (assume this needs to be distilled) and it should read 30 brix on the refractometer.

 

[dk21]

I get the conversion between Brix and OG. My concern was not one of simple conversion between the two units; but rather, the fact that the scales did not track throughout its range. Using your analogy, it would be tantamount to a thermometer to show a correct correlation of, say, 0C/32F, but not line up 100C/212F.

In the case of the refractometer, it shows a correct alignment at 0 Brix/1.000 O.G., but the correlation diverges at higher gravities. As a previous poster noted, 30 Brix should be 1.129, but displayed as 1.117 on the refractometer. This seems to be a significant error in the scaling.

You would be wise to ignore the SG scale on the refractometer. It serves well to give you an idea, but you can't really count on it to give you accurate results. The manufacturers would do well to stop putting SG scales on at all. I really don't fully understand why some refractometers need a wort correction factor. So far, mine (morebeer.com unit) is averaging a correction factor of 1, which evidently means the brix scale is already appropriate for wort. It's all complicated, but as far as I understand, just ignore that the SG scale is there, figure out your correction factor, and let the brewing software of your choice convert brix to SG for you.

Is there a chance it won't be spot on? Absolutely! This is a hobby, though...I'm not building rockets!

 

[MaxStout]

You would be wise to ignore the SG scale on the refractometer. It serves well to give you an idea, but you can't really count on it to give you accurate results. The manufacturers would do well to stop putting SG scales on at all. I really don't fully understand why some refractometers need a wort correction factor. So far, mine (morebeer.com unit) is averaging a correction factor of 1, which evidently means the brix scale is already appropriate for wort. It's all complicated, but as far as I understand, just ignore that the SG scale is there, figure out your correction factor, and let the brewing software of your choice convert brix to SG for you.

Is there a chance it won't be spot on? Absolutely! This is a hobby, though...I'm not building rockets!

Agree.

My concern was that I could not rely on either scale of the cheap Amazon instrument. Is the OG scale short, or is the Brix scale long? Or a little of both? Being off 12 gravity points (1.117 vs 1.129 for 30 Brix) is unacceptable when my lowly 10-buck hydrometer will get me to within a point or two.

Looks like the Morebeer unit you mentioned is fairly accurate, given the correction factor of 1. I'll look into that one. Thanks.

 

[dmcman73]

Ran into a glitch. I calibrated my refractometer in distilled water to read 0. I then noticed my hydrometer reads 0.998 in the same distilled water. Evidently, Brewzor doesn't plan for the hydrometer reading LOW because when I input those two values, it doesn't seem to accept it.

I'm seriously thinking about this plan:
1.) Trust my brix scale reading on my calibrated refractometer entirely.
2.) In Brewzor, use the calibrate feature by entering known values from the adjustement tables such as the brewersfriend tool. So if I pick a reading toward the middle say...16 brix...in Brewzor I enter 16 brix and a SG of 1.0654.

Basically then, I end up making the Brewzor app match up with the online calculators and then I throw all my faith into my refractometer's brix reading for unfermented wort. In this event, even with high gravity situations, I should always get a gravity value that matches the adjustment tools while still using one app to do all my calcs.

Sound ok or flawed?

Actually, the way it works is this:

If your hydrometer is reading 0.998 in distilled water, then you know you have to add .002 to all of your readings using the Hydrometer, that's how you "calibrate" the Hydrometer.

Now to calibrate the Refractometer calc within Brewzer, you have to use the values you read your Worth not distilled water. So, when you take your OG with your Hydrometer you enter that into Brewzer (remember to add .002 to that number since your hydrometer is .002 off) then measure your OG with the Refractometer and add that to Brewzer. That is how you calibrate it, it's doing a comparison.

 

[gr8shandini]

Seems like you have to calibrate your hydrometer as well. If you have distilled water at 4*C, it is by definition 1.000. However, most hydrometers are calibrated to read distilled water at 1.000 at 60*F, so either your temperature was high and you didn't apply the correction, you're reading it incorrectly, or your hydrometer is off.

Now the temperature correction on the refractometer works differently. It corrects for the temperature of the instrument, not the liquid - although the sample and the instrument will equalize in a few seconds. The ATC feature is usually only good for something like 50 - 80*F, so I always make sure to keep my refractometer inside if I'm brewing outdoors or in the garage outside of those temperature ranges.

Then, as mentioned there's a wort correction factor that would require you to use your calibrated hydrometer reading with temperature correction and your refractometer reading at the proper instrument temperature. That's if you want to be gnats ass about it.

If you think about it, we're making beer here, not cancer meds. The goal of using a hydrometer or refractometer is simply consistency and repeatability. If your readings are off by 10%, but always in the same direction, you'll still be able to re-create your favorite recipes. So, in my mind, it's not worth all that bookkeeping. But, hey, everyone needs a hobby, right?

 

[hops2it]

Now to calibrate the Refractometer calc within Brewzer, you have to use the values you read your Worth not distilled water.

Figured that might be the hangup. I'll retry with my next batch of wort. Also, I did get a reply back from the folks at homebrewstuff. Just when I was beginning to think nobody actually made an true, adjusted scale brix/SG refractometer, they claim theirs is in fact the real deal:

Hi,

You are correct the pic is an error. I tried to take a pic but I could not get it legible. Our Brewfractometer scale is ATC, when your read 30 brix the SG scale reads 1.129, Apposed to (dual scale refractometer) what the picture shows on the listing 30 brix = 1.117. With the ATC refractometers you will really notice a difference in higher OG gravity. As you go up on the scale the more off the two types become from each other, because the needed adjustment becomes greater as you go up the scale. I apologize for the miss pic in on website and have my IT Guys change out the pic.

Only thing that makes me wonder about the response is that ATC doesn't have anything to do with the scaling issue. Mine is auto temp compensating and it still has the old dual scale that doesn't change with increasing gravity. Anyway, if anybody can get a pic of a truly adjusted scale refractometer, it'd be appreciated if you'd post that, the model, and where it was purchased.

 

[dk21]

Seems like you have to calibrate your hydrometer as well.

Yes! I was initially puzzled why there was a large discrepancy. I threw my hydrometer in distilled water and temp corrected, it read four points high! That's frustrating, but now I know, and the readings are agreeing so far.

 

[dk21]

Agree.

My concern was that I could not rely on either scale of the cheap Amazon instrument. Is the OG scale short, or is the Brix scale long? Or a little of both? Being off 12 gravity points (1.117 vs 1.129 for 30 Brix) is unacceptable when my lowly 10-buck hydrometer will get me to within a point or two.

Looks like the Morebeer unit you mentioned is fairly accurate, given the correction factor of 1. I'll look into that one. Thanks.

It goes on sale (deal of the day) from time-to-time. I wanted to get one for a brew, so I just spent the $60. For what it's worth, while I ignore it, the SG scale has basically been pretty accurate for the two brews that did in the mid-50 point range.

I actually had originally purchased the Vee Gee BTX-1 from Amazon (I had points) but I got three defective refractometers (to be fair, two of the three were cosmetic defects, but for a $100 instrument, I expect it to be right). I decided to get the morebeer one instead and I've been pleased.

 

[hops2it]

Do you have a scale? If so, you can check on the brix by making a solution with sugar. Add 30 gram sucrose to 70 g water (assume this needs to be distilled) and it should read 30 brix on the refractometer.

Good thinking. Did that and got 30 brix. I'm calling that a 2 point calibration at zero and 30 which makes me trust the brix scale entirely on my refractometer. I'm going with my aforementioned plan of trusting the brix reading on my refractometer and "calibrating" the brewzor app with 16 brix = 1.065 sg. That'll give me instant brew day results for preboil and OG that match the correctly adjusted conversion talbes for increasing gravity. I do agree with an eariler poster that the rule of 4 would be adequate for most but my OCD wouldn't allow it. I'm satisfied now, even if it were overkill.

 

[gr8shandini]

Do you have a scale? If so, you can check on the brix by making a solution with sugar. Add 30 gram sucrose to 70 g water (assume this needs to be distilled) and it should read 30 brix on the refractometer.

By the way, that points out the other beautiful thing about using a refractometer: the Brix scale is simply the percentage of sugar by weight in the solution. It should be a more intuitive measure than SG, but unfortunately it's been hard for me to retrain my brain to "think" in Brix.

 

[Yooper]

The wort correction factor doesn't mean the brix/Sg scale.

It's actually a way to use your hydrometer and your refractometer, calibrated to each other.

From the link above (bold my own):

How to Determine your Refractometer’s Wort Correction Factor
When taking a refractometer measurement of wort, the Brix reading is not necessarily accurate. What is obtained is the Brix WRI (wort refraction index). Only after dividing the Brix WRI by the wort correction factor is the actual Brix known. It is helpful to know that Brix and Plato are nominally the same to 3 decimal places, so the corrected reading can be treated as Plato (°P).

The correction factor is needed because wort has a different density than sugar water which refractometers are designed for. The wort correction factor is specific to the instrument.

It's not that you need to correct the brix for the SG- it's the correction for YOUR hydrometer and YOUR refractometer.

Some helpful info: http://braukaiser.com/blog/blog/2012/03/23/dont-trust-your-refractometer-blindly/

 

[rico567]

I use my refractometer on brew day to test mash conversion, the SG of the first runnings, preboil, and get an OG sample at flameout. This is all so easy (I just do the x4 from Brix in my head, close enough) that it's well worth the $25 I spent on the instrument. On bottling day, I use my hydrometer to get an FG reading, just using a wine thief with the hydrometer inside. Once again, so simple that I'm not disposed to change, even though I could just use correction tables and employ the refractometer.

 

[slaithe]

Hey for that $25 refractameter, it does NOT have auto temp correction, right? Do you find that a feature you miss and might be worth paying for? Or? Seems like the only real extra features/justification for $30+...

 

[rico567]

I dunno- it said it did on the sheet I got with it.....I've never paid much attention, just checked its calibration with RO water and have used it ever since. It's one of those eBay specials from the Happy Fun Luck Trading Co. of Hong Kong, which means it's made You Know Where.

 

[jwalker1140]

Hey for that $25 refractameter, it does NOT have auto temp correction, right? Do you find that a feature you miss and might be worth paying for?

Mine is an eBay $25 special from Hong Kong and it has ATC. It works great so no need to spend more, IMO.

One note: be sure to calibrate it every day you use it! It does change. And tap water is probably fine for this. I've checked mine against distilled water after calibrating it with tap water several times and there's been no noticeable difference between the two. YMMV.

 

[mtnagel]

Thanks. That's good to know. I never tested it with tap water. Of course I'm sure it depends on what's in your tap water. As you said, YMMV.

 

[mtnagel]

So I'm brewing this weekend and I finally thought to make some sugar solutions to test out my refractometer. The results are below. At first I was freaked out because I made a 15.4 brix solution, but my refractometer said it was 17.8. But then I realized I was weighing some pretty small quantities on my scale, which is a cheap kitchen one with a minimum 1 g quantity and it doesn't give fractions of grams. So if I actually added 2.273 g sugar into 10.5 g water (which my scale would say 2 g and 11 g (assuming it rounds correctly)), that would be 17.8 brix, which is what my refractometer said. So basically the first one was within the error of the scale.

So then I started weighing bigger amounts and you can see the actual gets closer to the theoretical. I really should make some solutions on the 4 places scales at work to really test out the accuracy of this thing!

So I'm okay with a <1 brix error. Then for fun I read my crystal light drink and it was 1 brix. Yes I'm a nerd.

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