Final ABV Calculation?

[M38A1]

I'll readily admit I'm not great at math and I searched a couple threads on this and got lost. So any help would be appreciated.

I made a batch of SkeeterPee that came out at 10.5%ABV. SG 1.070 / FG .990 = 10.5%
I racked off just shy of three gallons, added 30oz of a strawberry daiquiri mix, three cups invert sugar, and 24oz of 190 proof EverClear. I have a full 3 gallon carboy now.

Can someone ballpark the final ABV on this based on what I provided?

 

[sour_grapes]

I'll readily admit I'm not great at math and I searched a couple threads on this and got lost. So any help would be appreciated.

I made a batch of SkeeterPee that came out at 10.5%ABV. SG 1.070 / FG .990 = 10.5%
I racked off just shy of three gallons, added 30oz of a strawberry daiquiri mix, three cups invert sugar, and 24oz of 190 proof EverClear. I have a full 3 gallon carboy now.

Can someone ballpark the final ABV on this based on what I provided?

I am willing to do so, but I am a bit confused. You say "just shy of 3 gallons," but then you added these other things, and now have 3 gallons? I think you added 30 + 24 + 24 fluid oz = 78 fluid oz? Is that right?

 

[Johnd]

I am willing to do so, but I am a bit confused. You say "just shy of 3 gallons," but then you added these other things, and now have 3 gallons? I think you added 30 + 24 + 24 fluid oz = 78 fluid oz? Is that right?

Paul, I think you’re correct in the added volume of 78 oz. My interpretation when he says he “racked off just shy of three gallons” he means: he had just shy of three gallons before racking, which would result in some volume loss to account for the .61 gallons of added goodies getting back up to a full 3 gallons.

 

[M38A1]

Yes, you are both correct!

First off, I made a mistake in my original post. I said 25oz 190 EverClear in the carboy and it was only 12.5oz. (I split this between two flavors and a 750ml bottle is 25oz so each got half of that 750)

I racked the SP off the gross lees from a 6gal carboy into two 3gal carboys. Then I removed "some" quantity to give me 'just shy of three gallons". I didn't measure, but it was just below the straight edge of the carboy where I presume that's the three gallon mark. Then I added the invert sugar (three cups sugar/1.5 cups water), PGA (12.5oz) and daiquiri mix (30oz) to bring it to between the carboy neck and the straight edge of the carboy. Picture attached to show where it wound up on the neck of the 3gal carboy.

I very much appreciate your tackling this. Next time I'm measuring exactly where the 3 gallon mark is and I'll measure more in/out volumes.

 

[sour_grapes]

Yes, you are both correct!

First off, I made a mistake in my original post. I said 25oz 190 EverClear in the carboy and it was only 12.5oz. (I split this between two flavors and a 750ml bottle is 25oz so each got half of that 750)

I racked the SP off the gross lees from a 6gal carboy into two 3gal carboys. Then I removed "some" quantity to give me 'just shy of three gallons". I didn't measure, but it was just below the straight edge of the carboy where I presume that's the three gallon mark. Then I added the invert sugar (three cups sugar/1.5 cups water), PGA (12.5oz) and daiquiri mix (30oz) to bring it to between the carboy neck and the straight edge of the carboy. Picture attached to show where it wound up on the neck of the 3gal carboy.

I very much appreciate your tackling this. Next time I'm measuring exactly where the 3 gallon mark is and I'll measure more in/out volumes.

Starting with the inverted sugar solution: Calculators tell me that 3 cups sugar approx. equals 1.32 lbs. Fermcalc tells me that 1.32 lbs sugar + 1.5 cups water yields ~25 fl. oz. final volume.

Next we figure out how much SP you started with. You ended with about 3*128 fl oz = 384 fl oz. You added 25 fl oz sugar solution + 30 oz. daiquiri mix + 12.5 oz everclear. I am going to say this equates to 67 fl. oz. Please note that, believe it or not, volume is not conserved when you mix alcohol and water. I am largely ignoring this; I will just round down from 67.5 to 67 oz. So you must have started with about 384 - 67 = 317 fl oz.

Next we find how much ethanol you started with. You had 317 oz * 10.5% = 33.3 fl oz. ethanol in the SP, and 12.5 oz * 0.95 = 11.9 fl oz in the everclear, for a total of 45.2 fl oz.

Your final ABV was 45.2/384 = 11.8%.

By the way, did you stabilize this concoction before adding the sugar and daiquiri mix, or is it still subject to further fermentation?

 

[M38A1]

Thank you for the calculation explanation. I'm surprised the ABV doesn't go up much by adding the PGA. Then again, I really didn't know 'how' much it would go up either and in the big picture it's a small quantity to a large volume in my head.

Yes - this has been stabilized with k-meta/k-sorbate 12 days ago. Sugar/PGA/concentrates were added last night and I've seen no new fermentation.

Again, thank you.