Refractometer Advice Please

[Trent]

Gday all
Wondering if my refract has had it, or if it is OK, but I have a little problem. I bought a refract a few weeks ago, and was quite impressed with it, so impressed I managed to drop it on its head on the concrete while taking the OG for my very first brew with it! It gave me a few wildly varying results, then settled down to be pretty much inline with my hydro. Last night I was doing my second brew with it, it seemed pretty good all the way through, hit my boil gravity OK, and after the boil, I took my refract reading and it read 17.4 brix (1069) when my target gravity was 1072, and my hydrometer read about 1071. I also use spiese to prime my beers, so when I bottled my latest porter the other day, that was 1055 OG, the refractometer read a drop of that at 13.2 brix (1053). The hydro seems to be calibrated OK, and so is the refrac, so what gives with the 2 point variation? Is this normal, and which one is correct? I know that 2 points is bugger all in the grand scheme of things, but wanna know if I buggered my refrac by dropping it. I bought it so I could really dial in my IBU's, I would hate to think it is now useless. Any info would be greatly appreciated.
All the best
Trent

 

[Joel]

You should be able to recalibrate it. The instructions that came with it should tell you how.

Distilled water should read 0, if it doesn't then simply adjust the little thingy (techo terminology!) until it does.

 

[Trent]

It was actually recalibrated just before I took my reading. I dont have any distilled water, and so I calibrate it with filtered water, could this be enough to create a 2 point/ 0.5 brix difference? The sample was taken at 18.5C out of the fermenter before any yeast had been added.
Trent

 

[bradmcm]

You need to test it against another refractometer.

What kind of hydrometer have you got - a good professional one, or a cheapy homebrew store one? I'd also test that too if it's a cheapy.

 

[Trent]

Brad
My hydro is a cheap homebrew type one. I should be able to test my refrac against that of a mate in the next couple of weeks, so I will try that. Thanks for the idea, so simple, yet probably more effective than anything I woulda come up with!
All the best
Trent

 

[Weizguy]

Trent,

Time for a short reminder on how these things work. That might clear up the difference in OG estimate.

The refractometer measures sugar content, yes?
The (cheapy, same as I have) hydrometer measures the density of the dissolved contents of the solution.

Maybe they are both OK. I can imagine that there may be dissolved components in the wort which are not sugars and may add to the density, rather than fermentables.
Therefore you might get a higher OG from the hydro.

Due to the hydrometer only providing an estimate of the sugars, based on average sugar density, and not the actual sugar content, I'd be keener to rely on the Refractometer estimate of sugars.

My twopence worth of input. (yeah,I know it's tuppence, before Warren gets me on this).

Seth out (for a Cuban birthday cigar later this evening, on the verandah, out in the bush, under my Birthday full moon, baying like a wolf, and listening to the hellish mating sounds of fruitbats/ flying foxes)

 

[pint of lager]

Easy way to get some distilled water is to use a few drops from the lid of a kettle, or, hold a teaspoon over the spout of a boiling kettle. You only need a few drops that condense on the teaspoon for enough to do a calibration on your refractometer.

Very sorry to read that you dropped it. I know of another forum memebr that dropped his, it broke in two. He has rejoined the parts, recalibrated and it now works fine.

 

[Trent]

Thanks Seth and POL
I guess that there was a bit of break/hop trub in the hydro thingy, and that could have skewed the reading, so that makes me feel a little better. And knowing that someone has actually broken their refractometer in two, repaired it and it still works OK is very good news to me indeed (not the bit about someone else breaking theirs though!) I will go and try the kettle trick now, and see if it was out at all.
All the best
Trent