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historian

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Is there a way to determine the percent alcohol of a beer without using a hydrometer to measue OG and FG?

I found a recipe in Extreme Brewing that aims for a very high alcohol brew by adding sugar throughout the brewing process, in order to not shock the yeast at the onset. But if I do this, I will be screwing with the gravity throughout, so it will be impossible to get an OG i can trust.

I can estimate the alcohol content based on the fermentable sugars, but for a high gravity brew I'm sure that the yeast efficiency will start to be limited. (there is an addition of distiller's yeast at one point to try to keep things growing.)

Am I stuck telling people a wild guess when I brew it, or is there a better way?
 
Sure! Just enter all the ingredients into Beer Smith or Beer Calculus or something similar as if they were all going into the boil. It'll give you your expected OG and FG. It won't be exactly what you end up with, but should be within a few tenths of a percent as long as your brew doesn't go way off.
 
I was planning on doing that, but for a high alcohol brew I was afraid that the yeat might poop out before it go to the estimate. Do you think that will be considerable, or minor?
 
Well, off the top of my head, if you have an accurate scale, you could take a sample of the end product, weigh it, boil off the alcohol at 173°F, weigh it again to find out the alcohol by weight. Then multiply that number by 1.25 to get the ABV.
 
If you have a precision scale, weight out 25 gm of brew. Place it in a water bath and heat to 180F. After 15 minutes, remove from heat and re-weight. That will give you water by weight. ABW is the difference.
 
menschmaschine said:
Well, off the top of my head, if you have an accurate scale, you could take a sample of the end product, weigh it, boil off the alcohol at 173°F, weigh it again to find out the alcohol by weight. Then multiply that number by 1.25 to get the ABV.
Click to expand...

Your head and my head sure work differently :D
 
I took a shot at this and apparently my Holiday Brew is 20%. Who knew!

Actually, I am pretty sure it is 8% and somewhere my measurements got f'ed. Likely I evaporated some water with the alcohol. Geez, I wish this actually worked!
 
A better way to do this is to take a beer sample of a known volume. test gravity. Boil it a bit and don't worry if you boil off water as well. Then let cool and top off with water to the initial volume. Test gravity again. With these two readings (apparent FG and real FG) you can determine OG, alcohol and all the other parameters.

I'd have to dig up the formula.

You can also determine OG and alcohol from a hydrometer and a refractometer reading. That's what's done in in-line monitoring systems in breweries. But they use oscillating U-tubes and sound velocity AFAIK.

Kai
 
noblesquirrel said:
that will only measure sugar in solution, you can't use it after fermentation for a reliable number, though it will give you a great OG.
Click to expand...

This device is supposed to be use post fermentation to give the % alcohol by volume. Though the amount of sugar in the liquid will affect the reading, so it is meant for dry wines but it will give you a close estimate.

http://www.monashscientific.com.au/Vinometer.htm
 
Interesting approach, Kaiser. I suspect one would need a precision hydrometer to get useful data.

passedpawn - try doing it with a good thermometer in the beer and stop the process as soon as the temperature goes above 173F.
 
david_42 said:
Interesting approach, Kaiser. I suspect one would need a precision hydrometer to get useful data.

passedpawn - try doing it with a good thermometer in the beer and stop the process as soon as the temperature goes above 173F.
Click to expand...

I do use a Fluke 54 II Thermometer, so I trust the numbers (to the nearest 0.1C). I think the oven would be a better place to do this than the microwave, though, which is where I heated the water.

On a side note, my Holday Brew tastes very poor when hot and alcohol-less.

I just bottled some apfelwien... I think I'll go again with that stuff.
 
Kaiser said:
A better way to do this is to take a beer sample of a known volume. test gravity. Boil it a bit and don't worry if you boil off water as well. Then let cool and top off with water to the initial volume. Test gravity again. With these two readings (apparent FG and real FG) you can determine OG, alcohol and all the other parameters.

I'd have to dig up the formula.

You can also determine OG and alcohol from a hydrometer and a refractometer reading. That's what's done in in-line monitoring systems in breweries. But they use oscillating U-tubes and sound velocity AFAIK.

Kai
Click to expand...

You can do with with real FG and real OG

A = (OE-RE)/(2.0665-.010665*OE)

A := alcohol % weight
OE := original extract
RE := real extract

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.
 
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!
 
remilard said:
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.
Click to expand...

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
 
Erythro73 said:
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!
Click to expand...

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.
 
Kaiser said:
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
Click to expand...

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.
 
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
 
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.
 
I think it would be sufficient to try this technique on a few beers for which you know the OG.

Kai
 
Thanks for all the great responses!!! I will definately estimate the OG, but I'm glad there is a way to check my estimation.
 
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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