If my refractometer has been spot-on with my hydrometer for over a dozen beers (most were between 1.050 and 1.065), is there any reason to doubt it's accuracy on a real heavy (1.100) wort?
refractometer accuracy
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Two questions: How high does the scale go? Does your unit do auto temp correction?
OP
OP
The refractometer claims it does auto temp correction, altho it doesn't exactly take more than a minute for the couple drops to cool to room temperature (the whole wort is already down to 83F). But my hydrometer only goes up to 1.070, so I can't double-check. I only ask, because my gravity came in a little lower than expected (1.088 vs 1.101) on an extract batch.
It's prob'ly accurate enough for homebrewer work. Gravity can shift down if you don't get as much water boiling off or you added not quite as much LME or adjunct sugar as your recipe suggests.
Did you scrape out those cans like they owed you money? Did you weigh out your sugar vs. use a volumetric measure? Those things can throw off the figures by a few points.
Did you scrape out those cans like they owed you money? Did you weigh out your sugar vs. use a volumetric measure? Those things can throw off the figures by a few points.
1.088 vs 1.101 is a pretty big miss for all-extract. If the recipe was correct to begin with and followed faithfully I'd be inclined to believe the sample was drawn from less than fully homogenized wort...
Cheers!
Cheers!
OP
OP
That's why I was questioning if the refractometer maybe gets a little less accurate at higher gravities... I suppose if I dilute my hydro sample with equal parts water (hmm, by weight? or by volume?) I should be able to get a good hydrometer reading...
Then again, I had a lot more steeping grain and hops (than I usually use) that surely soaked up some wort, that likely got replaced with top-off water.
Then again, I had a lot more steeping grain and hops (than I usually use) that surely soaked up some wort, that likely got replaced with top-off water.
[edit] Either way it's the top-up water that usually is the culprit 
Cheers!
Cheers!
NSMikeD
Well-Known Member
Yes, a hydrometer becomes less accurate as it measures liquids that move away from where it was calibrated. Perhaps not as much as what you're experiencing. Also. keep in mind that temperature affects readings for both hydrometers and refractometers and automatic corrections are not always precise, again, less so as you move away from room temperature.
fwiw, whenever I get a questionably reading I usually attribute it to user error which almost always is confirmed weeks later by my taste buds.
fwiw, whenever I get a questionably reading I usually attribute it to user error which almost always is confirmed weeks later by my taste buds.
jerrylotto
Well-Known Member
I have a pretty cheap refractometer, and recently it was giving inaccurate results. I finally figured out what happened. When washing it off, some water slipped past the glass and was inside of the unit. I was able to wick it all out with a dry towel and the accuracy I used to have came back.
BrewnWKopperKat
ʘ‿ʘ
Without supporting information, an OG miss of this size could be due to a missing ingredient; but ...
... with top-off water, stratification is a likely cause as well.
Measuring the dilution will need some precise measurements. Maybe measuring dilution by weight and volume would be a good cross-check.
Another approach might be to build a solution using simple sugar; take an SG measurements for solutions at around OG 50, 70, 90, 110.
There are some additional ideas in the /r/homebrewing wiki refractometer page.
Last edited:
OP
OP
Since the hydrometer is measuring the amount of sugar in a specific VOLUME, I think diluting with equal parts by volume would have to be the way to go.
I've decided to just leave it be, it'll just be touch lighter on the ABV*. Now, if that whole pack of US-05 I added about 12 hours ago would stop slouching and ACT BUSY, I'd be so much less worried!
*say, that'd leave space for a little bourbon flavor...
Zambezi Special
Well-Known Member
I was going to suggest a dilution so you can use your hydrometer.
Use half wort (properly mixed) and half water. Mix very well again.
Check hydrometer and multiply by 2
Use half wort (properly mixed) and half water. Mix very well again.
Check hydrometer and multiply by 2
AZ Maverick
Well-Known Member
If you want to check your refractometer at the high end you can make a sugar solution to test it.
I zero tare a small container on my kitchen scale then add 14 grams of table sugar and then add water until the scale reads 50 grams and then mix it very well - that is a 28% sugar solution (or 28 Plato). 28 Plato is 29.1 brix or 1.120 SG.
My ATC refractometer reads in brix and is dead on 29.1 brix with the above 28% sugar solution.
I zero tare a small container on my kitchen scale then add 14 grams of table sugar and then add water until the scale reads 50 grams and then mix it very well - that is a 28% sugar solution (or 28 Plato). 28 Plato is 29.1 brix or 1.120 SG.
My ATC refractometer reads in brix and is dead on 29.1 brix with the above 28% sugar solution.
OP
OP
Beer went from 1.088 down to 1.015 (so 9.5% abv), and has been sitting there for over a week. I've got about 2.8 gallons to bottle (guesstimating, not quite sure how deep the yeast cake is). Is there any kind of rule-of-thumb for ounces of bourbon to add to one gallon? I know the usual suggestion of dosing a small sample until the taste is good, and then scaling that up -- but that's not terribly practical when the beer still has a good hop burn and zero carbonation.
What's the hurry? Let it be for a month, it may still creep down ever so slowly.
OP
OP
I don't trust the plastic bucket with 2 gallons of deadspace to keep oxygen out (plus my own general impatience)!
well if the refrac was right, it should read 10.5 now?
and that gravity i'm assuming was corrected right?
and that gravity i'm assuming was corrected right?
I've had problems with my refractometer occasionally reading really low; like 7 brix when it's really 11 or 12. I'll double-check it and get the same reading. I messed up one beer (didn't quite ruin it) by adding a pound of DME and the beer didn't have that much hops to balance it. I think what is happening is a little bit of grist is getting on the glass so the coverplate isn't sitting level. I'll have to watch for that.
OP
OP
I'd have sworn I'd recorded the original brix reading when I brewed this, but I can't find my notes on this one, so all I've got to go off is this forum thread, where post #3 says I got 1.088 (I always use Refractometer Calculator - Brewer's Friend with a 1.04 wcf). Anyways, it was a DME extract batch, and I'm quite certain the "miss" was adding too much top-off water.
i meant if you take a gravity AND BRIX reading you can punch it into a calc to get ~OG.... and right now with it finishing at 1.015, if the wort did start at 1.088, the refrac should read 10.5 now?
OP
OP
Correct, hydro said 1.015, refractometer reads roughly halfway between 10 and 11 brix.
OP
OP
My googling would indicate that somewhere around 13 to 14 ounces bourbon would be reasonable in a 5 gallon imperial... That's like 2.5 ounces of bourbon per gallon. I'm going to go for it! Wish me luck!
jambop
Well-Known Member
Just finished doing a hydrometer /refractometer results check over four different worts cooled to the correct temperature and homogenous. If we concider the hydrometer to be the standard and taking five refractometer readings for each wort and comparing the average reading with the calibrated hydrometer ... I could have saved myself some time and not bothered the largest difference I could get was 0.001 sgu which in my book is not significant and not worth worrying about . I have read a bit about cheap refractometers being inaccurate and non reproducible. I have to conclude the operators were not using properly cooled and homogeneous samples as my one is cheap and I could not separate the refractometer results from the hydrometer results .
fusa
Senior Member
You can test your refractometer with this Amazon.com: Continuum Reagents Refractometer Calibration Standard – Seawater Reference for Calibration of Density Measuring Equipment, 60 ml : Industrial & Scientific
That's for salt water.
You can make your own calibration solution with sucrose and water, that's how Brix came about.
Weigh both your sugar and distilled water on a small 1/100 gram precision scale (~$15). A scale like that is useful for many other small weighing tasks, such as brewing salts, dry yeast (baking and brewing), etc.
Weigh both your sugar and distilled water on a small 1/100 gram precision scale (~$15). A scale like that is useful for many other small weighing tasks, such as brewing salts, dry yeast (baking and brewing), etc.
My refrac was way off during my last brew a few days ago. I had measured some pre-boil wort and it read quite low. Thought, maybe mash efficiency was low, but took a hydro sample, cooled it to 60F, and I got 6 points higher using a hydrometer I know is very accurate.
The next day I checked the cal of the refrac. With some distilled water at 60F, it was spot-on 1.000, as was the hydrometer. I mixed some sugar water, measured 1.042 with a hydrometer, the refrac showed 1.035. Took a couple more readings, cleaning and drying the refrac surfaces between each. Still 1.035. Trouble is, the refrac is single-point calibrated. If I adjust it up to 1.042, the bottom end of the range (pure water) shows 1.007. Move one end, the other moves with it accordingly.
No idea what had happened to the refrac. I take loving care of those instruments.
I ordered a new one for $20 on Amazon.
The next day I checked the cal of the refrac. With some distilled water at 60F, it was spot-on 1.000, as was the hydrometer. I mixed some sugar water, measured 1.042 with a hydrometer, the refrac showed 1.035. Took a couple more readings, cleaning and drying the refrac surfaces between each. Still 1.035. Trouble is, the refrac is single-point calibrated. If I adjust it up to 1.042, the bottom end of the range (pure water) shows 1.007. Move one end, the other moves with it accordingly.
No idea what had happened to the refrac. I take loving care of those instruments.
I ordered a new one for $20 on Amazon.
For the 1042 test, what was the observed reading in Brix?
OP
OP
Shoot, I always figured once it's accuracy had been confirmed between pure water and a couple different worts of known (via hydrometer reading) gravity, it was pretty much guaranteed to be accurate until you dropped and broke it...
I don't recall. Maybe there became some non-linearity between the two scales.
I thought so too. Maybe I'll make up some vials of sugar water for testing, maybe 1.040 and 1.080, and keep it around to check from time to time.
One other thing... Checking my notes from the other day, I did notice something odd. The first sample of the pre-boil wort I looked at in the refrac had a spurious reading of near 1.000. The whole viewfinder was blue. I wiped it clean, drew another sample and got the low reading (1.051). A couple more tries showed the same 1.051. The hydro showed 1.057.
jerrylotto
Well-Known Member
Check that water hasn't gotten inside your unit sneaking past the glass while washing it. Using a paper towel, you should be able to wick it out if it's in there. I had this problem and it threw readings off until I got the inside dry again.
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I had the same issue as @jerrylotto , kinda sorta.
Mine would not revive with a wickable solution.
Of course, I dropped mine into the boiling wort, so, ya know, subtle difference there.
Mine would not revive with a wickable solution.
Of course, I dropped mine into the boiling wort, so, ya know, subtle difference there.
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