Proper ABV calculation when adding whiskey

Hi All,

I'm working on adjusting one of my favorite recipes from Northernbrewer. The Bourbon Barrel Porter kit calls for the brewer to add in bourbon soaked oak chips to the secondary for conditioning. Well the first time I read the directions, I messed up it by adding the entire bottle of Makers Mark into the secondary. In the end I was actually very pleased with the beer, just needed to let it sit a while longer in the secondary, and then keg condition for 2 extra weeks. The whiskey was not overpowering at all, even to some of my family who don't like whiskey.

I've just started using BeerSmith, and was hoping to document this recipe properly. I've searched the site and just haven't come up with an answer that will help me calculate the final ABV. I've been to a few homebrew tastings, and while this beer is very popular, it sucks not being able to answer what its true ABV is. Any help is appreciated. I'm excited to start using this tool going forward with the 1gal experiment batches my wife and I are working on.

I'm not sure you'd find much help in BS2 for this issue.

I think it's just the math involved with figuring out what happens to 90 proof MM (45% alcohol) when it is diluted across 5 gallons (or whatever). 

A 1/5 is about 25 oz, I believe.  So the blended average of 640 oz of beer at xx ABV and 25 oz of 45% alcohol.  You'd have to verify that ABV means the same thing from beer to booze, or find the conversion. 

It's just a dilution calculation. Maltlicker's bottle size represents 750ml size (25.4 oz), the most popular one.

45% of that can be rounded to 11.5 oz of alcohol.

The net size is the bottle plus the batch, in oz. Divide the alcohol oz by the total oz.

11.5 / 665.4 = .017 or 1.7% alcohol by volume added to the base beer.

I've used whiskey on a few occations and by doing the calculations I've determined that a pint of 80 proof liquor adds exactly 1% ABV per 5 gallon batch.  How you set that up in Beersmith ingredients is something that I haven't taken the time to figure out though.