Alcohol measurement

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GIBSON77
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Alcohol measurement

Post by GIBSON77 »

There are several methods of measuring the alcohol content of a liquid some of the principal methods are :

Density and Refractive Index method:
The refractive index of alcohol is different from water, so can be used as an indicator of alcohol content. It is the quickest method, taking only a few minutes. It is prone to interference by other compounds in the wine, but the accuracy is dependent mainly on correcting for the temperature of the wine, a sophisticated refractometer will have a temperature compensation facility, the accuracy can be at best +-0.5 %vol.

Distillation followed by hydrometry/refractometry method:
The alcohol must first be separated from the wine by distillation with special equipment. The specific gravity of the distilled alcohol is then determined with a hydrometer which is calibrated directly in %vol at 20 °C. If the distillate temperature varies from 20 °C then a correction needs to be applied, since the volume of the liquid changes with temperature. 0.1 %vol is added for each 0.5 °C below 20 °C, or subtracted for each 0.5 °C above 20 °C, so this is very significant.
This is a complex and time consuming procedure, the accuracy can be affected by the work of the technician as there are various possible causes of error, such as interference from co-distilled compounds, when there are ethyl esters (cleaved to ethanol during the analysis) and other alkali-stable steam volatile compounds present.

Gas chromatography (GC) method:
The equipment is expensive to buy so the analysis is normally carried out by contract analytical chemists. It is considered to be the most accurate means of ascertaining the alcohol content of wines and is used by HM Customs & Excise.

Essentially, the gas chromatograph works by analyzing the mixture of organic compounds found in the wine. The gas chromatograph has a series of filters made from porous materials. Samples taken from the wine batch are gathered into a syringe and then injected into an ejector port on the device. The temperature of the injector port must be in excess of the boiling point for the sample in order accurate readings to occur. This allows the components of the wine to convert into gas, which then is then pushed into the filters by way of helium or a similar carrier gas.
As the wine gases pass through the filters, the compounds are identified by electronic equipment and the alcohol content is determined. While some models of the gas chromatograph feature a printer that creates a graph of the progress of the wine sample, new models utilize a terminal display, making it possible to view the results without having to decipher a graph.
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Re: Alcohol measurement

Post by googe »

Strange first post :wtf:
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Re: Alcohol measurement

Post by ga flatwoods »

+1 googe.
Gibson77 you are either a scientist or plagiarist! Our hydrometers dont measure that close and some on here dont care as long as it tastes good! Some useful information you could have given is your background, why you are here, equipment you may have/may want, what you like to drink, and want to make, if anything. But anyway, welcome. Your next post should be in the new members posting.
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Re: Alcohol measurement

Post by Mike Lawry »

Chemistry 101?
GIBSON77
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Re: Alcohol measurement

Post by GIBSON77 »

Hey

Im new here but not new in distillaion business I had done my engineering Master on fermentation and distillation :egeek: .


it is nice to see that pepole that didn't learn formally chimical enginering, learn some of it here by this wonderful site, and distillation is not simple to learn if you want to plan your own still.

so.. as for this post "Acohol measurment" didn't be mentioned at all here , a forum that pepole talk about and making alcohol, Ithink that its can be nice to know.
for example if you want to know the composition and concentration of your distil fractions you can know then by using GC (gas chromatography) but its not attainable o every body.

for your question I like to drink and to make grapa and some plump/ shnaps I made my own reflux still 25mm X 1000mm, and going to make my next still reflux 50mmX1200mm. and learnig to make a good wiskey.

chimistry 101? sorry if it was over studying :crazy: if you know chemistry it will help you understand process in distilling and fermentation....
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Re: Alcohol measurement

Post by bluenose »

nice read... I'm looking forward to your next post where you explain how to use the fluxflabulator to recognitize the rasmatan

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Re: Alcohol measurement

Post by Prairiepiss »

Sometimes its hard enough to get people to use a $6 hydrometer. And the other methods aren't real practical for home distilling. But nice post. Odd for a first one. But still nice.
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Re: Alcohol measurement

Post by Xecros »

Prairiepiss wrote:Sometimes its hard enough to get people to use a $6 hydrometer. And the other methods aren't real practical for home distilling. But nice post. Odd for a first one. But still nice.
I certainly use mine. :thumbup: I prefer to know just how much potential alcohol i have in my wash prior to a distillation.
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Re: Alcohol measurement

Post by Jimbo »

If you have a refractometer and a hydrometer, there is a neat trick to learn the alcohol content of your fermented wash, even if you didnt take a SG, by just plugging both readings into this calculator. http://www.northernbrewer.com/refractometer-calculator/" onclick="window.open(this.href);return false;" rel="nofollow

For example, if your current brix is 6.2 and gravity 1.002 the ABV of yoru wash is 7.8%. I have this calculator bookmarked and use it quite a bit, handy.
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Re: Alcohol measurement

Post by Prairiepiss »

Jimbo wrote:If you have a refractometer and a hydrometer, there is a neat trick to learn the alcohol content of your fermented wash, even if you didnt take a SG, by just plugging both readings into this calculator. http://www.northernbrewer.com/refractometer-calculator/" onclick="window.open(this.href);return false;" rel="nofollow

For example, if your current brix is 6.2 and gravity 1.002 the ABV of yoru wash is 7.8%. I have this calculator bookmarked and use it quite a bit, handy.
Maybe I don't quite understand brix. I never use it. But how the flip can you get the ABV of a fermented solution only knowing the brix and SG of that solution? I take it a brix refractometer only gives you an actual sugar reading. And is not influenced by the alcohol content. Or anything else in there. Where a hydrometer is actually influenced by the alcohol. So it compares the two. And takes the difference between the two as the alcohol content?

Now that is something that could be very useful. Thanks for that post. :thumbup:
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Re: Alcohol measurement

Post by Jimbo »

Prairiepiss wrote:... how the flip can you get the ABV of a fermented solution only knowing the brix and SG of that solution?

Now that is something that could be very useful. Thanks for that post. :thumbup:
haha, I shared your surprise and awe too P when I first stumbled on that calculator. I think my reaction was just about identical. No idea the science behind how or why it works, but it does.
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Re: Alcohol measurement

Post by Prairiepiss »

Makes me want a refractometer now. Damn you. :evil:
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Re: Alcohol measurement

Post by Jimbo »

LOL, surely you can afford 25 bucks Mr. 40 gallon wash guy. :mrgreen:

http://www.amazon.com/s/ref=nb_sb_noss_ ... ractometer" onclick="window.open(this.href);return false;" rel="nofollow


Edit: PS: you want one that does automatic temp comp. ( No idea how that science works either :think: )
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Re: Alcohol measurement

Post by bowhunt76 »

GIBSON77 wrote:Hey

Im new here but not new in distillaion business I had done my engineering Master on fermentation and distillation :egeek: .


it is nice to see that pepole that didn't learn formally chimical enginering, learn some of it here by this wonderful site, and distillation is not simple to learn if you want to plan your own still.

so.. as for this post "Acohol measurment" didn't be mentioned at all here , a forum that pepole talk about and making alcohol, Ithink that its can be nice to know.
for example if you want to know the composition and concentration of your distil fractions you can know then by using GC (gas chromatography) but its not attainable o every body.

for your question I like to drink and to make grapa and some plump/ shnaps I made my own reflux still 25mm X 1000mm, and going to make my next still reflux 50mmX1200mm. and learnig to make a good wiskey.

chimistry 101? sorry if it was over studying :crazy: if you know chemistry it will help you understand process in distilling and fermentation....

*Chemical* i believe is the correct spelling.......just sayin.
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Re: Alcohol measurement

Post by Prairiepiss »

bowhunt76 wrote:
GIBSON77 wrote:Hey

Im new here but not new in distillaion business I had done my engineering Master on fermentation and distillation :egeek: .


it is nice to see that pepole that didn't learn formally chimical enginering, learn some of it here by this wonderful site, and distillation is not simple to learn if you want to plan your own still.

so.. as for this post "Acohol measurment" didn't be mentioned at all here , a forum that pepole talk about and making alcohol, Ithink that its can be nice to know.
for example if you want to know the composition and concentration of your distil fractions you can know then by using GC (gas chromatography) but its not attainable o every body.

for your question I like to drink and to make grapa and some plump/ shnaps I made my own reflux still 25mm X 1000mm, and going to make my next still reflux 50mmX1200mm. and learnig to make a good wiskey.

chimistry 101? sorry if it was over studying :crazy: if you know chemistry it will help you understand process in distilling and fermentation....

*Chemical* i believe is the correct spelling.......just sayin.
From a few of his words. I gathered American English isn't his first language. So not sure about that. Hope not to offend the op by saying that.
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Re: Alcohol measurement

Post by bowhunt76 »

No off fence intended just givin the context of the post thought was funny. I applegize
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Re: Alcohol measurement

Post by Jimbo »

Hellaryus.
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Re: Alcohol measurement

Post by GIBSON77 »

Prairiepiss wrote:Makes me want a refractometer now. Damn you. :evil:
hey, you can measure a lot of parameters like alcohol,Brix Degrees, concentration of lot of material (liquid stage) , to use a refractometre you need you solution to be clear.

The refractometre is good enough for low concentration, I found that when I used it. high concentration (measured after reflux) gave me strange result.

here I attache one of my refractometer measurement, It is the concentration of my pear mash after fermenting, I did it before some years.
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Re: Alcohol measurement

Post by Jimbo »

GIBSON77 wrote:I found that when I used it. high concentration (measured after reflux) gave me strange result.
ya think? its not an alcometer for distilled ethanol. It measures sugar content.
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Re: Alcohol measurement

Post by krola »

Jimbo wrote: Sun Aug 25, 2013 9:59 am
GIBSON77 wrote:I found that when I used it. high concentration (measured after reflux) gave me strange result.
ya think? its not an alcometer for distilled ethanol. It measures sugar content.
A refractometer can measure the content of any given substance it has been designed for. :clap:
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