I am considering purchasing a refractometer to replace my hrdrometer.......I have read that they work great for pre fermentation measurements but that they can be a little inconsistant once fermentation has started and alchohol is present.......any input/experience?
Refractometer vs Hydrometer
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Oventoasted
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ill be purchasing one today also.
from what i understand you will need both during the whole process. what i read is a refractometer is good for brew during sparging to see what the gravity is coming out of the mash and, only needing a small sample size for your OG.
also not needing to waste time cooling it down to get an accurate reading with the hydrometer will be nice too.
In my opinion, a refractometer is a must with all grain during brew day. There are some fairly accurate conversions out there to get a reading with one after fermentation, but I always check with a cheap hydrometer. You should just get both.
One doesn't replace the other. They're both useful at different stages. The hydrometer is way more accurate than the refractometer once alcohol is in the beer.
This is my take on it also. You really want both. If just one you should opt for the hydrometer.
I use both. I take a sample of the first wort with the refractometer. If something has gone wrong, I consult this page http://merrycuss.com/calc/gravityadjustmentextract.html. After that, I use the hydrometer.
I guess it depends on what is your priority. For me, doing all grain batches, the refractometer is indispensable. I can check the gravity of my first runnings, I can check the gravity as I'm pulling the last of the lautering to make sure I'm not going too low, I can check the pre boil gravity to see if I'm high and want to add water to the kettle, or low and want to boil off a little longer,...
If the final gravity reading (after plugging into existing refractometer correction spreadsheets out there and in BeerSmith) is maybe not that accurate I'm not that worried. I do get consistent readings so I'm still able to confirm fermentation is done. And the final gravity readings after correction do come out where expected, so I've had no issues with it.
Getting rid of that dumb sample beaker filling which always involves dribbling some beer somewhere and the reading of those lines while looking at the miniscus (who even wants to use that word anyway?), tipping of the hydrometer, etc. I think there is probably just as much or more repeatability and reading accuracy errors just due to all of this. And the cost argument didn't work for me, as I seemed to find a way to break my hydrometer about every 4 months, so I easily paid for the refractometer after a few of those.
So I use the refractometer only and have never been happier. But this of course is personal preference depending on what you plan to use it for.
If the final gravity reading (after plugging into existing refractometer correction spreadsheets out there and in BeerSmith) is maybe not that accurate I'm not that worried. I do get consistent readings so I'm still able to confirm fermentation is done. And the final gravity readings after correction do come out where expected, so I've had no issues with it.
Getting rid of that dumb sample beaker filling which always involves dribbling some beer somewhere and the reading of those lines while looking at the miniscus (who even wants to use that word anyway?), tipping of the hydrometer, etc. I think there is probably just as much or more repeatability and reading accuracy errors just due to all of this. And the cost argument didn't work for me, as I seemed to find a way to break my hydrometer about every 4 months, so I easily paid for the refractometer after a few of those.
So I use the refractometer only and have never been happier. But this of course is personal preference depending on what you plan to use it for.
btbnl
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I'm another refractometer user. Sure, you have to correct for alcohol post fermentation, but there are plenty of calculators out there. The big upside for me is only needing a drop of beer rather than half a pint.
That said, I do still have a hydrometer on hand in case something seems really funky with the refractometer readings (I'm looking at you, Russian Imperial Stout).
That said, I do still have a hydrometer on hand in case something seems really funky with the refractometer readings (I'm looking at you, Russian Imperial Stout).
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A refractometer is more useful to me during the brew day, but I use a hydrometer once the wort is in the fermenter to compare OG to SG. On my next brew I plan to use a residual sugar kit to determine when to transfer from the fermenter to the keg.
How do you correct for alcohol ? Wouldn't you need Fg to know the ABV in order to make correction?
Natdavis777
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I enjoy both. I always use my hydro for post fermentation samples though. Im am in need of a new refractometer though, because my last one was way off on readings regardless of calibration and temp.
btbnl
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Pre-fermentation = Refractometer
Post-fermentation = Hydrometer
Two good reasons why I prefer the hydro for post-fermentation over the refracto....
1) no calculators needed to figure out FG
2) you get to drink the sample.
Post-fermentation = Hydrometer
Two good reasons why I prefer the hydro for post-fermentation over the refracto....
1) no calculators needed to figure out FG
2) you get to drink the sample.
I like to use both. The refractometer gets me pretty dialed in during the mash and boil. And I determine I am at FG through static refractometer readings. But I still take one hydro reading right before pitching yeast and a second right at packaging. I don't know why, but I find determining ABV through the hydro readings more straight forward.
btbnl
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Ok...I was just reading that....and now my head hurts.
Wort correction factor?
Yeah - just calibrate your refractometer against your hydrometer, taking the latter to be the correct reading. Mine comes out at 1.04 for a 1.050-ish wort.
Meaning that 1.04 is your wort correction factor?
I've been running side by side checks with my two hydrometer a and my refractometer on pre and post fermentation gravities. I use Sean Terrill's spreadsheet and it always gets me within half a point or less. I did make one adjustment to the spreadsheet though because the default had me coming in .001 low every time so I just added a column that adds the .001 for me.
Soon I'll stop taking hydro measurements I think, except for stouts that can be a bit hard to figure out where the center of the line is.
Soon I'll stop taking hydro measurements I think, except for stouts that can be a bit hard to figure out where the center of the line is.
btbnl
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Exactly - refractometers are (typically) calibrated with sugar water, and wort has a slightly different refractive index.
Ok..thank you... <sigh> my Refractometer that was supposed to simplify my brew day has suddenly become a bit of a hassle .... At least it was free... Is wort correction factors equally necessary for pre-fermentation readings if all your interested in is OG? Maybe I'll just stick to hydro for FG. I check the Refractometer with RO to calibrate to 0 .... Sounds like tha s only half the job
I almost exclusively use a refractometer now, and employ Sean Terrill's correction calculator and consistently come within 1 point of gravity checked with hydrometer. I find it simple, using the stock wort correction factor.
btbnl
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It's really not that complicated! Next time you measure a gravity, do it with both and take the ratio
hydrometer reading/refractometer reading
which will be very close to 1.
Then whenever you take a refractometer reading, multiply it by this number (or use a calculator, like the one I pointed you to, that does it for you).
I've found that my refractometer is indispensable. I bought one on a whim after my third hydrometer bit the dust, and I am confident enough to ditch my hydrometer entirely. Although it requires some slight calibration to understand the wort correction index, once that factor is found it can be used way more easily than a hydrometer for pre and post fermentation gravities.
Sample size is tiny.
Temperature corrections are not required.
Sanitation is simple.
More robust than a hydrometer.
Additionally, I've found the following calculator to be an invaluable resource. It's always between +/-0.001 of my hydrometer readings and miles better than every other refractometer calculator out there (I use a WCI of 1.03):
http://seanterrill.com/2012/01/06/refractometer-calculator/
Sample size is tiny.
Temperature corrections are not required.
Sanitation is simple.
More robust than a hydrometer.
Additionally, I've found the following calculator to be an invaluable resource. It's always between +/-0.001 of my hydrometer readings and miles better than every other refractometer calculator out there (I use a WCI of 1.03):
http://seanterrill.com/2012/01/06/refractometer-calculator/
That's not quite it. That may work, but it doesn't match the actual science that's going on. The refractometer concept functions by looking at how light gets bent/refracted as it passes through your liquid sample. It's calibrated using distilled water that you know to be pure and you turn the set screw until it reads 1.00. From there, when you put on a sample that has "water + other stuff", the "other stuff" (aka wort sugars) causes that light to bend at a different angle, and then you read the gravity by where that reads. The more "other stuff" you have in there, the steeper the angle and in the refractometer you read a higher number.
But since you're comparing the light bend of your wort sample to how it bends through pure water, the comparison gets thrown off when alcohol comes into it. The bending of light as it passes through alcohol is different than when it passes through water. So that 1.023 you read might actually be 1.009, so you need to plug your reading into a conversion calculation (spreadsheet, BeerSmith tool, website calculator) to correct it.
Here's where these corrections are pretty close, but maybe not perfect. For me it's close enough, but for you, you might want to deal with the little glass bobber reading minuscuses (if that's really a word). The refractometer correction formulas ask you to plug in your OG. That's because they use that as an estimate of how much alcohol is in your wort to correct for how much the alcohol is messing around with the bending of light. Of course the OG doesn't tell your actual current ABV so it's just an approximation of how much alcohol is in there. So if you have a highly attenuated beer your actual FG might be lower than if you used a different yeast or mashed at a higher temperature, but the correction factor in the equations is the same. But as I've found, even varying mash temperatures and yeast strains with different attenuations, using my refractometer + these correction forumulas ends me up where the recipes are projected to be, so for me it's worked close enough.
But you need to use one of these formulas/calculators. If you came up with your own "correction factor" by comparing refractometer to hydrometer, that factor would only be correct for that ABV sample of beer. Works fine if you're always running around the same ABV beers, but if you vary ABV your "correction factor" is going to be off.
This link to Northern Brewer's website has calculators on there where you plug in Brix readings (since that's what most refractometers gauge in) and it spits out gravity readings (1.0xx).
http://www.northernbrewer.com/learn/resources/refractometer-calculator/
This is exactly how I do it to. I haven't use a hydrometer in months. I kept tabs on a few brews using the hydro. and the refractometer. Then I used Seans website to get my correction factor and as it turns out the difference is less than .002 for me. I figure that just reading the hydro. will account for that much error any way. Once I knew the accuracy was there with the refractometer, I went ahead and bought a digital model. My hydrometer is collecting dust. I kept it just in case I happen to break both of my refractometers.
FWIW the northern Brewer calculator is garbage. For example, my last batch had readings of OG 14.6 Brix and FG 7.2 Brix. The NB calculator predicts a corresponding FG of 1.009, while reasonable, is inconsistent with BeerSmith predictions, my own intuition and hydrometer readings (1.013). The margin of error on this one (predicted 85% AA v actual 78% AA) is unacceptable and worthy of dismissal.
In contrast, the Sean Terrill calculator arrives at my predicted FG and hydrometer reading (1.013) with a WCI of 1.03, which I've calculated from previous measurements.
In contrast, the Sean Terrill calculator arrives at my predicted FG and hydrometer reading (1.013) with a WCI of 1.03, which I've calculated from previous measurements.
btbnl
Well-Known Member
True for beer, but since we were talking about the wort correction factor I took the "wort" to be understood.
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