Blending liqueur to increase ABV and flavor.

[Grod1]

So i have a stout that fell short on abv and the percentage of cholaca was way to small to give any flavor.(32 oz/12 gallons)
Long story short i am going to blend a chocolate liqueur to the beer to increase the abv and get more chocolate flavor. I have two separate 5 gallon batches that will get two different products I am not set on anything and would love any suggestions. a quick google search yields these Bottega Nero - Cioccolato Nero e Grappa (Dark Chocolate)/Mozart Dark Chocolate Liqueur as two good candidates.I would love to hear from anyone.

 

[Gameface]

Interested in the responses.

I make a strong bitter (ESB) a lot and have considered adding liquor to make a British Strong Ale.

This is for competition as my Strong Bitter has done really well over the last 6 years and I've entered it unadulterated as a British Strong Ale and take third twice in three years. I figure a little alcohol bump might help it out a little.

 

[Grod1]

so i went with Godiva Dark Chocolate Liqueur basically because it was teh only one i was able to find locally. It cost less the the cholaca i bought in the first place. after reading reviews i am happy about the purchase. it basically has perfect ratings with most of the reviews saying something along the lines of"Godiva chocolate liquor is the best chocolate liquor ever. Smooth taste, not bitter. Great for mixing or drinking straight."
but the number one reason i got that one was because there is no dairy in it.
so i would love help estimating the ABV of my final product.
i have 5 gallons at 7.1ABV and i am going to blend in 750mls @ 15% alc by volume
a quick google search says
(Alcohol Content x Liquor Volume / Total Drink Volume) x 100 = % Alcohol by Volume
but im not the most math savy and im getting lost.
30 ABV x750ml/18927.1( 5 gallons) x 100=1892710 ??? i dunno what that means?
add 1.18 to the total abv of the beer?
i would love help from anyone.

 

[Grod1]

anyone good at math able to double check that ABV calculation? i failed remedial math at community college. I hope there is at least one person on this forum with the brains to tell me if im wrong.

 

[bucketnative]

Beer: Vol = 18.9 L, ABV = 0.071 -> ABV*Vol = 1.34 L alcohol total in beer
Liquer: Vol = 0.75 L, ABV = 0.15 -> ABV*Vol = 0.11 L alcohol total in liquer
Beer + Liquor -> (1.34 + 0.11) L alcohol / (18.9 + 0.75) L drink = 0.074, or 7.4 %ABV