#### jonp9576

##### Well-Known Member

then i added a half of a handle of 21% abv rum to the beer. and ideas on how to figure out the new abv

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then i added a half of a handle of 21% abv rum to the beer. and ideas on how to figure out the new abv

- Thread Starter
- #2

does this math make any sense?

if you figure that a handle of rum is 1/2 gallon. then half would be 1/4.

would it work this way. there are 20 quarter gallons in 5 gallons.

so if you divide 21(the % abv of the rum) by 20(to dilute it into 5 gallons)

you get .0105. so am i basically adding 1% abv to my brew going from 5.74% to 6.74%

if you figure that a handle of rum is 1/2 gallon. then half would be 1/4.

would it work this way. there are 20 quarter gallons in 5 gallons.

so if you divide 21(the % abv of the rum) by 20(to dilute it into 5 gallons)

you get .0105. so am i basically adding 1% abv to my brew going from 5.74% to 6.74%

1. Are you sure the rum was 21% ABV? That's awfully low; more like 40% is typical, but we'll go with it.

then i added a half of a handle of 21% abv rum to the beer. and ideas on how to figure out the new abv

2. How much beer was there? Suppose 5 gallons.

5 gallons = 18927 ml. Of that, 18927 (ml of liquid) *.0574 (your ABV) = 1086.4 ml is alcohol.

You can double-check the math: (1086.4/18927) = .0574, your ABV

1/2 handle = 875 ml. Of that, 875*.21 = 183.8 ml is alcohol

So your new total alcohol = 183.8 from rum + 1086.4 from beer = 1270.10 ml of alcohol.

Your new total volume is 18928 beer + 875 rum = 19802 ml of liquid.

1270.1/19802 = .064

So that would be 6.4% ABV in the new mix.

Beer Alcohol Volume (5g) x 5.74% = .287 G (you have .287 Gallons of alcohol in the beer)

Rum Alcohol Volume (.132G=500ml) x21% = .022772 G

-----------------------------------------------------

=.31472 Gallons of alcohol in the whole thing.

Divide volume of alcohol, in this example .31472 by total volume of all liquids - in my example it would be 5.132 G =

EDIT: dammit, beat to it plus I didn't have your measurements - I was going off 500ml of rum, not 1/4 gallon....

5 Gallons @ 5.74% = .287 Gallons of Alc.

.875 L ( .231151 Gallons) @ 21% = .18375 L of Alc (or .0485416 Gallons)

5 Gallons + .231151 Gallons (Rum Volume) = 5.231151 Gallons total Volume

.287 Gallons + .0485416 Gallons = .335416 Total gallons of Alcohol

.3355416 G / 5.231151 G = 6.41%

Which is pretty close to your estimate, so they both make sense to me.

You may want to get a 2nd opinion, however.

What the hell kind of rum is 21% (42 proof) abv?

Remind me not to buy that stuff.

Remind me not to buy that stuff.

Assuming a standard handle of liquor is 1.75 l:Here's the equation i believe:

Beer Alcohol Volume (5g) x 5.74% = .287 G (you have .287 Gallons of alcohol in the beer)

Rum Alcohol Volume (.132G=500ml) x21% = .022772 G

Rum was 1/2 handle = 875 ml = .231 Gallons = .049 G of alcohol.

Yep, same as mine except you converted everything to G instead of ml.

5 Gallons @ 5.74% = .287 Gallons of Alc.

.875 L ( .231151 Gallons) @ 21% = .18375 L of Alc (or .0485416 Gallons)

5 Gallons + .231151 Gallons (Rum Volume) = 5.231151 Gallons total Volume

.287 Gallons + .0485416 Gallons = .335416 Total gallons of Alcohol

.3355416 G / 5.231151 G = 6.41%

Which is pretty close to your estimate, so they both make sense to me.

You may want to get a 2nd opinion, however.

It's an okay estimate, but:

if you figure that a handle of rum is 1/2 gallon. then half would be 1/4.

would it work this way. there are 20 quarter gallons in 5 gallons.

so if you divide 21(the % abv of the rum) by 20(to dilute it into 5 gallons)

you get .0105. so am i basically adding 1% abv to my brew going from 5.74% to 6.74%

1. You're ignoring the increase in the total volume and

2. A handle of rum isn't 1/2 gallon, though it's kind of close. A half handle is about .231 gallons. So you're inflating your alcohol estimate there.

EDIT:

And

3. Are you totally sure that rum is 21% ABV? That's very low. I've never seen anything like it.