When making an ice beer how do you calculate ABV?

[dfc]

Let me start by saying I completely understand that using OG and FG you can determine the ABV, but what happens when you begin ice brewing? How can you determine ABV in this process? If you remove the ice (ultimately removing water) then obviously the wort becomes more dense therefore increasing your gravity readings.

Does anyone know the formula to determine ABV in this process?

 

[MalFet]

If you can figure out your original ABV and then measure the quantity of water that you are removing in the icing process, it's just a proportional change.

I.e., 5 gallons of 5% beer is equivalent to 2.5 gallons of 10% beer.

This assumes that no alcohol is lost during the icing, which may or may not be true depending on how you go about it.

 

[plaidpaint]

Does removing ice/water from the beer increase the density?

The point is to remove water, thereby increasing the alcohol content. So the resultant solution has less volume, and a proportionally higher percentage of unfermentables, so I see your point that the SG should go up. However, it will also have a higher percentage of alcohol, which has a lower SG than water, bringing the SG back down. I don't know how these things would balance out, I just thought I'd try to confuse the matter a bit

But MalFet's solution makes sense.

 

[MalFet]

Does removing ice/water from the beer increase the density?

The point is to remove water, thereby increasing the alcohol content. So the resultant solution has less volume, and a proportionally higher percentage of unfermentables, so I see your point that the SG should go up. However, it will also have a higher percentage of alcohol, which has a lower SG than water, bringing the SG back down. I don't know how these things would balance out, I just thought I'd try to confuse the matter a bit

But MalFet's solution makes sense.

Huh? Your voodoo math is making my head hurt

None of the stuff you are describing impacts abv.

 

[GilaMinumBeer]

If you are Ice concentrating there is no wort. It has been fermented already. Thus the density of the beer would be dilute by the increased alcohol content at the resultant volume. I would suspect that it may be as simple as taking the concentrated SG and doing the OG to FG calculation to determine the final ABV given that the tested sample volume does not change but the alcohol ratio does.

 

[MalFet]

ABV = volume of alcohol / total volume

New ABV = Old ABV * Old Volume / New Volume

This assumes of course that remove no alcohol during icing.

 

[JebCkr]

I'm fairly sure you'll end up removing some of the alcohol in the process. I read an article on it once and the conclusion was your best bet is centrifuge, otherwise the alcohol is trapt in pockets of the ice.

Plus, I think jacking falls into the distilling category...

 

[CoolHandLuke]

Jacking is concentrating. At least the feds say so here .

Enjoy!

 

[Rentachik]

Download Beersmith. Measure the fermented wort with a hydrometer and a refractometer. Punch in the numbers under the refractometer tool and it'll calculate the OG and the ABV. Easy as pie

Brad