Refractometer vs hydrometer

[hmmmbeer]

I’ve just started AG brewing and worry more about fermentable wort levels than I did with extract/partial brewing. I was wondering if there is a difference in using the simple hydrometer and using a refractometer?
Thanks in advance!

 

[jaycount]

A refractometer is great for a quick, low volume,pre-fermentation wort sample. I use it for preboil og and starting gravity.

I use a hydrometer for final gravity. it is more accurate than a refractometer once there is alcohol in the beer.

 

[BrewThruYou]

Honestly, I have a refractometer and barely use it. I use my hydrometer all the time.

I feel that the refractometer would be good if you are REALLY trying to hit your OG perfectly...so before the boil, you can add DME or lengthen the boil to raise gravity or dilute or take late runnings to lower gravity. Either way, I don't care enough that the OG might be 1.065 versus 1.067 to even make that refractometer reading.

 

[Homercidal]

I like my refractometer for seeing what is going on before I start boil, etc. I also use it after fermentation, as I seem to get a decent reading with compensation software, but honestly, a hydro reading is about as easy to get at that point.

It's MUCH faster and easier to take a gravity reading with hot wort because you can cool that tiny sample down in a few seconds. With a hydro, that same thing can take quite a while.

To me it's totally worth the $40 I spent.

 

[ajf]

The best things about refractometers (as far as I am concerned) are:

1. They don't roll off the kitchen counter top and smash into thousands of pieces.
2. They don't require a large sample.
3. You don't have to wait excessive times for the sample to cool. I fly sparge, and with lower gravity beers, I usually have to stop the sparge when the gravity of the runnings gets down to about 1.010. Stopping the sparge at 2.5 brix is simple. Using an hydrometer is very difficult.
4. With my eyesight it is more accurate than an hydrometer, where I'm lucky to be able to read within 4 points.
5. If you continually check the gravity to see when fermentation is finished, you can do the same with a refractometer. When the brix reading is static over 3 - 4 days, it is done. Then, you can use an hydrometer to see what the gravity really is, and you only need one sample, leaving you with more beer to drink.

-a.

 

[nebben]

I thought my new refractometer was the cat's ass when I first started using it. For all the reasons that ajf points out, I loved using it.

Then one day, I tested a sample of unfermented wort with my refractometer and my hydrometer simultaneously. I discovered that while hydrometers measure liquid density (all dissolved sugars), refractometers aren't all created equal in what kinds of sugar they measure. My observed gravities differed by ~12 points for the same sample on the different instruments. It turns out you can compensate for this, but needing to go back to beersmith or some other electronic device in order to calculate what the observed refractometer value really means turned me off on the whole idea.

Refractometers are still cool, but when yours doesn't measure maltose accurately and needs a computer to calculate correct readings...yea, I will stick with my hydrometer and deal with it.

 

[weirdboy]

Then one day, I tested a sample of unfermented wort with my refractometer and my hydrometer simultaneously. I discovered that while hydrometers measure liquid density (all dissolved sugars), refractometers aren't all created equal in what kinds of sugar they measure. My observed gravities differed by ~12 points for the same sample on the different instruments. It turns out you can compensate for this, but needing to go back to beersmith or some other electronic device in order to calculate what the observed refractometer value really means turned me off on the whole idea.

There is a calibration button in beersmith. All you have to do is enter in the hydrometer reading, and the corresponding refractometer reading. After that it is basically set, and at least in my experience, I have never had to change this setting since doing it a couple years ago, even though I still regularly check both hydrometer and refractometer for my OG sample going into the fermenter.

 

[Spartan1979]

I thought my new refractometer was the cat's ass when I first started using it. For all the reasons that ajf points out, I loved using it.

Then one day, I tested a sample of unfermented wort with my refractometer and my hydrometer simultaneously. I discovered that while hydrometers measure liquid density (all dissolved sugars), refractometers aren't all created equal in what kinds of sugar they measure. My observed gravities differed by ~12 points for the same sample on the different instruments. It turns out you can compensate for this, but needing to go back to beersmith or some other electronic device in order to calculate what the observed refractometer value really means turned me off on the whole idea.

Refractometers are still cool, but when yours doesn't measure maltose accurately and needs a computer to calculate correct readings...yea, I will stick with my hydrometer and deal with it.

It sounds like you bought the wrong refractometer.

 

[JiltedEmu]

@nebben make sure your refractometer is still calibrated by measuring distilled water. The calibration can get thrown off when you check the gravity of hot wort. Make sure the gravity level of the distilled water is still 1.000

 

[hmmmbeer]

Thank you to all that replied, I think I'll stick with what I know and have loved... my hydrometer... sounds like its a "Ford vs Chevy" pissing match... what has worked for me seems to work for all (in a nut shell)

 

[Gwitz]

I love my refractometer, but i have found its finicky if you dont have the liquid on there just right. You kinda have to have an idea of where your wort should be, and always double check with a hydrometer.

 

[nebben]

I have done the 1.000 calibration with distilled water when I first started using it and numerous times over the years.

While we are talking about this, I would be curious how everyone else's hydrometers/refractometers agree or disagree. When I first found out about this, it sounded like this is a common thing since < $100 hydrometers aren't made for maltose and dextrose, but for sucrose instead or something.

 

[Flomaster]

my Refractometer is spot on I trust it more than my hydrometer for unfermeted wort. my hydrometer is .07 points off when measuring distilled water at 60F. so having to add those .07 points sucks if you can't remember if you added them or not.

and using my refracto on fermenting wort is CLOSE ENOUGH.... Refracto 1.010 vs hydrometer 1.012 of coarse you need to use a online calculator to figure the readings of beer.

-=Jason=-

 

[samc]

I don't like Refractometers very much, but I've finally found a use for it that I like. That is being able to take a tiny sample of fermenting wort and quickly tell if I'm near completion. It doesn't have to be super accurate as I'm only relying on it to clue me in for a D rest or dry hopping start. For accuracy sake I'm fine with a Hydrometer and subtracting 4 due to it's calibration needs.

 

[Henry22]

I used to be into Saltwater tanks real big and bought a refractometer to use to measure the salinity of my tank. It was quite a big joke in the online community for people to use hydrometers because they were so inaccurate. This were the swing arm design and look different from the ones used in home brewing but it was always understood that refractometers were way more accurate in SG readings.

But I have yet to receive my kit and the hydrometer it has. Has anyone compared readings?

 

[JiltedEmu]

I bought my refractometer for $40 from Austin Homebrew Supplies and I've been quite happy with it. Its readings usually match my hydrometer, so most of the time I don't even bother with the hydrometer.

 

[Henry22]

Do you calibrate your refractometer with RODI or distiller water? I used spring water after not having using it for years and am afraid it won't be exactly accurate.

 

[wailingguitar]

I have used both in a commercial setting. The refrac ended up being used almost exclusively for testing high gravity wort during vorlauf. Basically vorlauf would keep running until gravity reached a certain point, then begin runoff to kettle. Every brewery that I have ever worked in preferred hydrometers to refrac for many of the reasons already stated.

 

[kh54s10]

I use my refractometer for every reading. I also take an OG and FG with my Hydrometer.

I get numbers that are close, inconsistent with the refractometer after fermentation so I am only looking for stable numbers to confirm fermentation has ended.

 

[JiltedEmu]

Do you calibrate your refractometer with RODI or distiller water? I used spring water after not having using it for years and am afraid it won't be exactly accurate.

I use distilled

 

[mikeysab]

My hydro and refracto are one point off. I used distilled to calibrate. I like using the refracto to figure out first running grav, then second to see if I need any adjustments to boil time or add some dme. My latest brew session wad a partigyle, so the refracto came in handy.

I agree with the person who stated it's a bit finicky at times. Sometimes I can barely see a difference in the color, so its hard to tell where the line is. I hope its not busted, it was dark the first couple times I used it.

 

[Ibrewaletx]

I typically do small batches now (3 gallons) and pouring off enough wort to do a OG, and several FG's makes very little sense. The addition of my refractometer into my brewery has been quite a nice luxury to have.

A guy named Sean Terrill has done some work recently on the refractometer calculations for wort with alcohol (i.e. when measuring for FG), and has improved tremendously the previous calc's out there (i.e. From your favorite software).
He has a spreadsheet you can download or just use the calc straight from his website, well worth a look if you use a refractometer.

 

[ChemLab]

I used to work in a chemical processing plant that used hydrometers, refractometers, and auto specific gravity sensors. Honestly, they all work. If you can spare sample for a hydrometer, go for it. I personally love my refractometers-it requires very little for a sample and is dead on to 0.0X. I brew 1 gallon batches, so I appreciate not having to draw a sample for a hydrometer reading from my carboy.

 

[flyingfinbar]

Having just smashed two hydrometers (yeah, not my brightest brew day), I've been considering going the refractometer route. At this rate, it would pay for itself in about 4 brew days

I've heard such mixed results, though. Still on the fence, and I've been enjoying this thread

 

[jedijon]

Here's some thread necro from a scientist.

I've got a $300 refractometer & numerous precision hydrometers at work so accuracy isn't an issue. It's what a prior poster was observing - that there's not parity between the two measurements.

I've checked this pre and post ferment on beer and just recently on pre-ferment wine must. My most recent measurement was 25 BRIX on the hydrometer scale and 22.5 BRIX with the refractometer.

It doesn't have to do with what sugars these measure; it's not like one of them is ignoring your monosaccharides...however, the refractometer is ignoring some of the real large stuff like the pulp or starches.

I have a centrifuge so I'm going to try that to see if I can prove that suspended - but not dissolved - solids are what is making the difference here. Of course, the starches are probably also dissolved...and those are changing the density also...but that shouldn't be a factor in wine so that's what I'll conduct my experiment on. It WILL be a factor in beer - but I'm not sure I'm that curious to throw some wort into the vacuum oven and come back 24 hours later to see what's left after the water has evaporated into the vacuum...

 

[mwwhited]

Did you ever run your test?

 

[trnitz]

I just used my new refractometer yesterday, after calibrating it with distilled water. After calibration, it was spot on, matching the hydrometer exactly.

Assuming everything still matches up, I'll use the refractometer for OG readings, as the sample size is smaller, aka waste less potential beer in doing readings.

 

[Clonefan94]

I use my refractometer for everything pre-fermentation. I don't have a set up that allows easy drining of enough of a sample to test hydrometer readings post boil, so just a few drops is easy for me to get out of the pot.

I calibrate my refractometer every time I use it. I do this in the kitchen, where I know the tempereature is stable, and I just leave it there and bring my samples in to test when needed.

One thing I found, is where the variations started to happen between my hydro and my refracto, were when I was using it outside. I would usually calibrate it early in the morning. roughly 50 - 60 degrees ambient temp. Well, by the time the boil was done and I was testing OG, the temp would usually be around 70 or 80 degrees. My refractometer was off due to the fact it was calibrated to 20 or so degrees below what it was actually reading at.

That's why I leave it in the kitchen now. It's always 72. or at the very least, it's a stable temperature. Since then, and the 4 tests I have done, my hydrometer and refractometer are spot on with each other.

And I have one of the well under $100 models.

 

[danorocks17]

I just purchased a refractometer a few months ago after 3 years of AG brewing. I love it. I use my hydrometer as well for FG, and sometimes for the OG if I think the refractometer is being funny, but I like being able to pull a little wort off while it's cooling to see where it's at. I know hydrometers are temperature dependent for you to get an accurate reading, which can be an issue if you aren't to pitching temps yet.

 

[Smellyglove]

I think it's a hit or miss gamble with refractometers, as it is with hydros too. I've read tonnes of people complaining about their refractometer. One factor many of them have in common is that it was a cheap hydro from china. I've had refractometers where the scale is off, and I'm not the only one.

I got tired of having a scrap-refracto, so I put a little bit more money in a new one, still from china, which is spot on, I even use it for post-fermentation, and after a quick conversion, I get the same number as with my hydro. The biggest deviance I've had pre fermentation and post boil is 0.5 pts. Takes a couple of tries, but still.

 

[squash1978]

One thing I found, is where the variations started to happen between my hydro and my refracto, were when I was using it outside. I would usually calibrate it early in the morning. roughly 50 - 60 degrees ambient temp. Well, by the time the boil was done and I was testing OG, the temp would usually be around 70 or 80 degrees. My refractometer was off due to the fact it was calibrated to 20 or so degrees below what it was actually reading at.

^ this

I store my refractometer in the basement and found that I get much more accurate and consistent readings when I would do my readings in the basement rather than outside where it is warmer.

Another thing that contributed to inaccurate readings when I first got my refractometer is that I wasn't letting my wort samples cool sufficiently. Letting the wort sample cool down to room temp and then letting it sit on the prism for another minute or so did the trick.

Making these two changes puts my refractometer on par with my hydrometer. I was initially frustrated with the refract b/c of the inconsistent/inaccurate readings but in the end it was because I was not using it correctly.