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Old 11-02-2009, 12:11 AM   #21
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if you have a hrdrometer with potential alcohol itll read within probably 2%/vol

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Old 11-02-2009, 12:50 AM   #22
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Take x days in a year, separated by at least 1 day (to recover). This interval must be the same between all x.

At each of these x days, you follow the same schedule. You sleep (the night before) the same number of hours, you eat the same things at the same moment, etc. At each of these days, at a given moment, you start drinking. At each day, you drink at the same rate (one beer / 30 min, as an example).

At each of these x days, you only drink of the same beer. What is important is the alcohol content. You calculate the number of beers required before you're drunk, and to do so, let's take something precise, like "When I'll vomit, then I'm drunk." So you count the number of beers taken before you're drunk.

You start with your beer and see how much beer you need to get drunk.

Then, you do it with commercial beer who states their alcohol content. You start with 5%, 6%... till 12%. You compare it with your beer, and you can evaluate your alcohol content with a simple linear extrapolation!

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Old 11-02-2009, 01:30 AM   #23
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Originally Posted by remilard View Post
The problem is that boiling beer for a bit will evaporate all of the ethanol about as well as boiling a sugar and water solution for a bit will evaporate all of the water, which is to say poorly enough that you would be better off using apparent extract to estimate the alcohol content.
The idea is that you want to boil enough to get all the alcohol out of the sample but you don't care if some water is boiled off as well since you will be topping off with water to the original volume anyway.

This is actually a standard method of determining beer alcohol although these days they use beer analyzers that work based he aforementioned principles.

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Old 11-02-2009, 01:49 AM   #24
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Quote:
Originally Posted by Erythro73 View Post
Take x days in a year, separated by at least 1 day (to recover). This interval must be the same between all x.

At each of these x days, you follow the same schedule. You sleep (the night before) the same number of hours, you eat the same things at the same moment, etc. At each of these days, at a given moment, you start drinking. At each day, you drink at the same rate (one beer / 30 min, as an example).

At each of these x days, you only drink of the same beer. What is important is the alcohol content. You calculate the number of beers required before you're drunk, and to do so, let's take something precise, like "When I'll vomit, then I'm drunk." So you count the number of beers taken before you're drunk.

You start with your beer and see how much beer you need to get drunk.

Then, you do it with commercial beer who states their alcohol content. You start with 5%, 6%... till 12%. You compare it with your beer, and you can evaluate your alcohol content with a simple linear extrapolation!
this im sorry to say is waaaaay to long of an experiment that has too many variables involved to correlate a useful dataset to satisfy the parameters of said experiment.
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Old 11-02-2009, 02:24 AM   #25
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Originally Posted by Kaiser View Post
The idea is that you want to boil enough to get all the alcohol out of the sample but you don't care if some water is boiled off as well since you will be topping off with water to the original volume anyway.

This is actually a standard method of determining beer alcohol although these days they use beer analyzers that work based he aforementioned principles.

Kai
I think that will take quite a bit of boiling (certainly not a few minutes), and there is not a good way to know how long to boil without testing it empirically.

Of course if it is a standard method I'm guessing the standard isn't to "boil for a bit", do you have something more specific?

Mary Beth Raines recorded a 40% reduction in alcohol after 30 minutes of boiling, and I hope you would agree she is competent to perform the experiment.

http://hbd.org/hbd/archive/1609.html#1609-18

She got better results in the lab, the key lesson being we should be careful about sloppily assuming lab tests will work in superficially similar circumstances in the kitchen without empirically testing first.
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Old 11-02-2009, 02:28 AM   #26
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I'd have to give it a try myself. I don't think it's modern standard but definately a procedure I have found listed for real extract determination in a few places.

Kai

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Old 11-02-2009, 02:44 AM   #27
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I was thinking about doing an experiment with vodka diluted to beer strength, after convincing myself that I can detect ethanol in water at very low concentrations.

Other than that, I can't think of a way short of lab analysis to confirm that any method substantially removes alcohol and I frankly don't care enough to spend what I assume would be hundreds of dollars to have several samples tested.

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Old 11-02-2009, 03:55 AM   #28
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I think it would be sufficient to try this technique on a few beers for which you know the OG.

Kai

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Old 11-02-2009, 07:37 PM   #29
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Thanks for all the great responses!!! I will definately estimate the OG, but I'm glad there is a way to check my estimation.

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Old 11-02-2009, 09:33 PM   #30
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Thanks for all the great responses!!! I will definately estimate the OG, but I'm glad there is a way to check my estimation.

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