Refractometers

[C-Rider]

I've always read that the wort cools so fast when you put a drop or two on a refractometer that you don't have to pay attention to the temperature of the drops.

Well today I took a reading at the end of the boil and the Brix was 14 for and SG of 53. After it cooled down to about 75 I checked again just for the heck of it. Brix was 18 for an SG of 71.

Hmmm efficiency just went up. Think from now on I'll put a few drops aside for both pre and post boil readings.

BTW brewed up my Tiki Ridge Porter. Should have about 15 bottles in 6 weeks.

I haven't brewed for a month or two and my refer is just about empty. Only a few bottles of what's listed below left. Shame on me.

 

[MalFet]

A few drops should reach stable temperature in a matter of seconds. If you're getting significant jumps in gravity, make sure it's not actually a result of evaporation rather than cooling.

 

[C-Rider]

A few drops should reach stable temperature in a matter of seconds. If you're getting significant jumps in gravity, make sure it's not actually a result of evaporation rather than cooling.

No time to evaporate any thing.

Each time right out of the pot on to the meter.

 

[MalFet]

No time to evaporate any thing.

Each time right out of the pot on to the meter.

How much time are you talking about between reading one and reading two? You definitely need to give it 15ish seconds, but it shouldn't take more than that.

 

[Bobby_M]

ATC is about the device itself due to ambient temps and not the sample. Cool off your sample a bit in the pippette before dropping it on. A small cup of icewater is perfect for this.

 

[BulldogBrewer]

ATC is about the device itself due to ambient temps and not the sample. Cool off your sample a bit in the pippette before dropping it on. A small cup of icewater is perfect for this.

this is what I do. When comparing between the refractometer and corrected hydrometer, they are both very close.

 

[C-Rider]

How much time are you talking about between reading one and reading two? You definitely need to give it 15ish seconds, but it shouldn't take more than that.

First reading was when boil was finished.
Second reading was about 1 1/2 hours later after it cooled and I was ready to add the yeast.

 

[C-Rider]

this is what I do. When comparing between the refractometer and corrected hydrometer, they are both very close.

Since I bought the refractometer I only use the hydrometer at the end of fermentation. Less chance to introduce anything and I don't like to remove that much liquid as I"m only doing 1.75 gallon batches.

 

[MalFet]

First reading was when boil was finished.
Second reading was about 1 1/2 hours later after it cooled and I was ready to add the yeast.

Oh...so you're talking about two completely separate readings here. I thought you meant that you were putting a drop on the refractometer, reading it, and then reading it again a few minutes later.

I'm not really understanding what you're seeing, but something isn't right. When you put hot wort onto the refractometer, it will read low because of the temperature. But, the temperature of that drop will stabilize in seconds, not minutes, and certainly not hours.

 

[BulldogBrewer]

Since I bought the refractometer I only use the hydrometer at the end of fermentation. Less chance to introduce anything and I don't like to remove that much liquid as I"m only doing 1.75 gallon batches.

Well, all of my hydrometer readings are either pre or mid boil, so after reading, they go right back into the boil kettle. No worries about introducing anything there. The last one won't go back in, but that's the one I taste anyway

 

[C-Rider]

Well, all of my hydrometer readings are either pre or mid boil, so after reading, they go right back into the boil kettle. No worries about introducing anything there. The last one won't go back in, but that's the one I taste anyway

I usually take shot glass sample as it's coming out of the Colman Cooler for tasting.

OT. This time I poured the drainings back into the cooler over the grain twice. Picked up about 1 brix reading.

 

[C-Rider]

Oh...so you're talking about two completely separate readings here. I thought you meant that you were putting a drop on the refractometer, reading it, and then reading it again a few minutes later.

I'm not really understanding what you're seeing, but something isn't right. When you put hot wort onto the refractometer, it will read low because of the temperature. But, the temperature of that drop will stabilize in seconds, not minutes, and certainly not hours.

Yea that's what I've always thought. Next time I'll let it cool a few seconds and compare to the post cooling reading.

Mahalo for the comments.

 

[mmonacel]

I've had some discrepancy in readings as well to the point that I take at least two readings to make sure they're the same / close before I consider it final. I was thinking about putting out a post on this, but looks like someone else already did! Lately I've been taking a sample from the boil, putting a few drops on, and setting down the refract for a few min while I do something else. Usually when I do this readings are consistent.

ATC is about the device itself due to ambient temps and not the sample. Cool off your sample a bit in the pippette before dropping it on. A small cup of icewater is perfect for this.

Bobby - how long do you keep the pipette in the ice water for? How long after then dropping it on the refract do you then take your reading?

 

[Bobby_M]

I literally shake the bulb in the icewater for 5 seconds and drop it on the glass. That's all it takes and the reading is accurate right away and you don't leave the opportunity for an evaporation error.

 

[helibrewer]

I literally shake the bulb in the icewater for 5 seconds and drop it on the glass. That's all it takes and the reading is accurate right away and you don't leave the opportunity for an evaporation error.

Great method Bobby, I think I'll adopt it

 

[Dr1nkBeer]

still getting used to mine... took my gravity of my latest batch after moving to secondary.. it read 6.3 (7th day) so i run it through the calculator (excelsheet) and it said it was at 1.022... halfway there since i started at 1.049 (brix 12.2)... well something went wrong with the formula... i used the on-line version... and its saying with a brix of 6.3 and calculating for the alcohol.. i'm at 1.008..
Its done! :rockin: one day this device will make my life easier.

 

[C-Rider]

still getting used to mine... took my gravity of my latest batch after moving to secondary.. it read 6.3 (7th day) so i run it through the calculator (excelsheet) and it said it was at 1.022... halfway there since i started at 1.049 (brix 12.2)... well something went wrong with the formula... i used the on-line version... and its saying with a brix of 6.3 and calculating for the alcohol.. i'm at 1.008..
Its done! :rockin: one day this device will make my life easier.

The way I understand it once you start fermenting and producing alcohol you can no longer use the refractometer. Gotta use the hydrometer when you have some alcohol.

 

[iaefebs]

The way I understand it once you start fermenting and producing alcohol you can no longer use the refractometer. Gotta use the hydrometer when you have some alcohol.

Old wives tale. I think the problem is the people that bought refracts that displayed SG and not Brix. I think the rest are a little confused about how to convert a reading.

 

[MalFet]

Old wives tale. I think the problem is the people that bought refracts that displayed SG and not Brix. I think the rest are a little confused about how to convert a reading.

Groink?

Refractive index is reliably convertible to Brix in pure sucrose solutions. With unfermented beer, it's usually "close enough" for most people, though typically there's a variable calibration factor of around 4% or so, depending on the batch. Once fermentation happens, though, you need to make a number of assumptions to produce a correlation.

There are correction formulas out there, but even the better ones are routinely off by three or four points.

 

[iaefebs]

Groink?

Refractive index is reliably convertible to Brix in pure sucrose solutions. With unfermented beer, it's usually "close enough" for most people, though typically there's a variable calibration factor of around 4% or so, depending on the batch. Once fermentation happens, though, you need to make a number of assumptions to produce a correlation.

There are correction formulas out there, but even the better ones are routinely off by three or four points.

And look at the numerous threads on this site with people having problems reading a hydrometer. I've always said that while you have pulled a sample for your hydrometer ( if you don't trust the refractometer) just put a couple drops of that sample on the refractometer, use a calculator and compare...no harm no foul.

groink
Verbalized sexual euphemism, referring to the genital part of which it sounds similar to.

 

[MalFet]

And look at the numerous threads on this site with people having problems reading a hydrometer. I've always said that while you have pulled a sample for your hydrometer ( if you don't trust the refractometer) just put a couple drops of that sample on the refractometer, use a calculator and compare...no harm no foul.

I like refractometers too, though I'm not sure why some people's inability use a hydrometer leads you to believe that the ambiguities of correlating refractive index and density are just an old wives' tale. There are fundamental, physical limitations on how accurate a refractometer reading can be because the relationship between refraction and gravity varies from batch to batch.

 

[iaefebs]

I like refractometers too, though I'm not sure why some people's inability use a hydrometer leads you to believe that the ambiguities of correlating refractive index and density are just an old wives' tale. There are fundamental, physical limitations on how accurate a refractometer reading can be because the relationship between refraction and gravity varies from batch to batch.

This is why I say to just do a side by side test for yourself. If you draw off a couple of ounces of beer and have a hydrometer floating in it why not take an eyedropper or pipette or a straw and test the sample for yourself with a refractometer. If you are not satisfied with the comparison than continue to measure the way you are comfortable. An old wives tale is maybe the aluminum vs SS kettle.... using a secondary fermenter vs primary only.

 

[pwortiz]

wow. reading through this was....hurting my brain a bit. i thought i had had enough coffee today. I JUST received my refractometer from Austin http://www.austinhomebrew.com/product_info.php?products_id=1014 and I have realized I may have made a mistake and ordered the wrong one....because I don't have any idea of how to use the BRIX yet. I probably should have gotten this one - http://www.austinhomebrew.com/product_info.php?products_id=13092 - to take the guesswork out of all this.

Is there an easier way to understand the brix measurement or is it something you just have to learn to get used to?

 

[Sippin37]

wow. reading through this was....hurting my brain a bit. i thought i had had enough coffee today. I JUST received my refractometer from Austin http://www.austinhomebrew.com/product_info.php?products_id=1014 and I have realized I may have made a mistake and ordered the wrong one....because I don't have any idea of how to use the BRIX yet. I probably should have gotten this one - http://www.austinhomebrew.com/product_info.php?products_id=13092 - to take the guesswork out of all this.

Is there an easier way to understand the brix measurement or is it something you just have to learn to get used to?

There are BRIX to SG calculators/converters everywhere, just Google it. I also have a BRIX refractometer because it was cheaper and there is a converter in Beersmith so it doesn't bother me at all.

 

[MalFet]

wow. reading through this was....hurting my brain a bit. i thought i had had enough coffee today. I JUST received my refractometer from Austin http://www.austinhomebrew.com/product_info.php?products_id=1014 and I have realized I may have made a mistake and ordered the wrong one....because I don't have any idea of how to use the BRIX yet. I probably should have gotten this one - http://www.austinhomebrew.com/product_info.php?products_id=13092 - to take the guesswork out of all this.

Is there an easier way to understand the brix measurement or is it something you just have to learn to get used to?

There are plenty of easy to read charts that will convert Brix to SG. 1 brix equals 4 gravity points is a rough conversion.

There are two caveats, both intrinsic to refractive readings and equally true for brix and SG refractometers.
1) once fermentation has happened, your reading will be distorted by the presence of alcohol. There are various formula out there to correct for the alcohol, but their reliability is debated.
2) even before you ferment, your refractometer might need to be corrected for your wort. Refractometers are calibrated for pure sucrose solutions, and the complex sugars of wort behave slightly differently. I find I have to increase my brix reading by around 4% to match hydrometer-based brix readings.

 

[pwortiz]

There are plenty of easy to read charts that will convert Brix to SG. 1 brix equals 4 gravity points is a rough conversion.

There are two caveats, both intrinsic to refractive readings and equally true for brix and SG refractometers.
1) once fermentation has happened, your reading will be distorted by the presence of alcohol. There are various formula out there to correct for the alcohol, but their reliability is debated.
2) even before you ferment, your refractometer might need to be corrected for your wort. Refractometers are calibrated for pure sucrose solutions, and the complex sugars of wort behave slightly differently. I find I have to increase my brix reading by around 4% to match hydrometer-based brix readings.

holey moley....I have to admit i'm almost curious now why a refractometer might be better than standard hydrometer if you have to compensate that much? cooling half a cup of mash water/work and throwing that in a beaker should work just as well and may be even better? hmm....you have provided information that makes me wonder if i just wasted $50....i have some thinkin' to do. Thanks for the input!

 

[MalFet]

holey moley....I have to admit i'm almost curious now why a refractometer might be better than standard hydrometer if you have to compensate that much? cooling half a cup of mash water/work and throwing that in a beaker should work just as well and may be even better? hmm....you have provided information that makes me wonder if i just wasted $50....i have some thinkin' to do. Thanks for the input!

For what it's worth, I love mine and wouldn't trade it for anything. It's a great tool during the mash.