is there a tool available ($hundreds not thousands) that can accurately measure abv in finished beer? I will be experimenting with de-alcoholizing some of my beers. Thanks.
is there a tool available ($hundreds not thousands) that can accurately measure abv in finished beer? I will be experimenting with de-alcoholizing some of my beers. Thanks.
It really depends on the equipment but with the weighing method you'll be adding three separate errors:
- tare weight measurement error
- gross weight measurement error
- flask volume error
With the hydrometer you just have the hydrometer as a source of measurement error, so if it's a good (i.e. expensive) one chances are the measurement will be more accurate. But of course which method is acceptable also depends on how accurate you'd like your measurement to be.
Won't work in this case. This calculator works only by calculating the difference between OG and FG. Not FG and FG minus alcohol removed from the beer, as he intend to do.I've recently tried the following online ABV calculator ABV Calculator | Find The Alcohol Content Of Your Beer and it has worked just fine for me..!
It may not be accurate enough for your purposes but could you use a reliable Brix meter/refractometer and convert the result?
Correct... unfortunately... the measurement problem ended up being a giant PITA, but brewing ultra low abv is actually working pretty well.I don't think that wouldn't help @Dan K for what he was originally wanting to do. Refractometer "FG" readings have to be corrected to compensate for the presence of alcohol. I don't think the carefully tuned refractometer calculator formulae would work with a beer where the alcohol has been partially removed.
For a precise result you need an ebulliometre, or whatever this is called in English:
http://www.enologiavite.it/catalogo/Termometri-per-vino-grappa-mosto-birra-84/Ebulliometro-322/1
As you see they are new in the €5-600 range.
This is the instrument that is required in Italy and probably elsewhere for alcohol measurements when you have to deal with the Law. The instrument exploits the known relation between the temperature of the vapour and the percentage of alcohol in the beer (the higher the alcohol percentage, the lower the temperature of the vapour).
The method proposed by @Vale71 in #5 is not entirely accurate as it doesn't measure the alcohol which remains in the kettle, although the degree of inaccuracy might certainly be tolerable for your needs and it could be "good enough". Its error will always be by default though, which is probably not your preferred case.
i thought the refractometer reading compared to a hydrometer reading was good enough? now i'm wondering?
The original poster wants to brew a beer and then de-alcolize it with some method. The refractometer and hydrometer method will not work because they are based on the notion that sugars are converted into CO2 and alcohols according to a certain law, so the "missing" sugars in the beer are mathematically linked to the CO2 and alcohol which have been produced during the fermentation.
If then one eliminates the alcohol from the beer, the equations don't work any more.
hmm,...i thought it was a measure of the difference of SG reading between the two, that's how you can calculate the OG from the two together? i could be off? i was thinking of getting a refractometer so i could calculate ABV this way, let me know if i'm off on that.....
You absolutely can get a refractometer to evaluate the FG or the OG, and with the usual equations (or the usual calculators) you will then calculate the ABV of your "natural" beer, your non-dealcoholized beer.
The determination of the OG with the refractometer is practical but it has a small error due to the different refraction index between wort and a sugar solution;
The determination of the FG with the refractometer is practical but it has two small errors, one described above, and the other that you must know the OG and then apply an equation (several have been proposed) to arrive to the FG.
So, the hydrometer gives you the "physical" result, a direct measure of density, while the refractometer always gives you an indirect measure, with a small margin of uncertainty, but it's good enough for most purposes.
i thought it worked on the basis that alcohol effects a refractomometers FG reading? but not a hydrometer, thus comparing the two, you can calculate what the OG 'was', and thus ABV? or vice versa...but alcohol effects a refractometer, so comparing a refractometer reading to a hydrometer one, will tell you how much ABV? or so i'm convinced?
yeah, i know when alcohol is present refractometers don't work for a FG reading...that why comparing a refractometer FG reading to a hydrometer one will let you figure out how much alcohol is present? or so i've over heard people's text saying so.....and i've seen calculator that calculate it, better then the quick one i posted....
If you took the OG gravity, before fermentation, of that beer, you can use the refractometer to know the FG of that beer, which in turn allows you to calculate how much alcohol there is.
Comparing the refractometer FG reading to a hydrometer will not tell you how much alcohol there is, nor the refractometer reading will tell you that, nor the hydrometer reading.
What can be said is that comparing the refractometer reading (FG) with the hydrometer reading of the OG will allow you to know the alcohol in the beer. But that will work also if the OG is obtained with a refractometer instead of a hydrometer, the hydrometer being more precise though.
You need OG and FG to know ABV and it doesn't matter if you measure them with the hydrometer or the refractometer. You don't need a hydrometer to measure OG and FG and to calculate ABV.
What he's saying is the formulas have three variables- actual FG, refractometer FG, and OG. By knowing two of three you can derive the third. If you have the real FG via hydrometer AND the refractometer FG, you can reverse engineer the OG, as well as the ABV.
But that still isn't relevant for when the ethanol has been removed as the OP was originally asking.
so i'm not crazy? (or just plain wrong? lol) you might not be able to calculate OG if the alcohol was removed, but why not ABV?
would you need a different formula like compared to a sine or cosine?
or my English is really deprived of clarity
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