Cabernet Saison Update

I kegged my Cabernet Saison last weekend.  See the previous post about why on earth anyone would use Cabernet grape juice in beer, as well as how I went about doing it.  Though it still needs to finish carbonating and clearing a bit, it tastes awesome.

The Whitelabs Belgian Saison II yeast turned out to give off some very complex flavors.  There are absolute spice tones of clove and maybe a little pepper.  Surprising how a yeast can give off those flavors.  I used no spices in the beer.  The Cabernet grapes left very little actual grape flavor, but I do think gave the beer a bit of extra tartness.

I'm not exactly sure what the alcohol (ABV) ended up at, since I'm not sure if I did the calculation right. The problem is after I add the Cabernet juice to secondary, the gravity of course jumps back up and then continues to ferment for a couple weeks until complete.  So that throws off the calculations.  But I think I figured it out. Maybe a reader can check my work here:

My Original Gravity (OG):   1.058
Final Gravity after Primary Fermentation (Before adding Cabernet juice): 1.012
ABV: 6.0%

After adding Cabernet juice, gravity of beer = 1.018
Final gravity after fermentation with Cabernet juice= 1.011

So to calculate alcohol, I figured I should add the ABV resulting from the added juice to the first OG.
That would mean that the Cabernet juice contributed an extra .91% of ABV.  Added to the ABV from primary fermentation (6.0%) would equal total ABV of 6.91%  Right??  If anyone thinks different.  Please leave a comment.

Also, on a side note, I thought I was being real adventurous here with using the grapes in the beer.  I knew that there was a Sam Adams Longshot winner a couple years ago that did a Grape Pale Ale, and I've had Dogfish Head Midas Touch which I think also has grapes.  But then last week I had Stone Brewing's Vertical Epic 10.10.10.  It is made with Muscat, Sauvingon blanc, and Gewurtztraminer. And now I think I remember seeing a tweet that The Bruery got a shipment of Syrah grapes recently, so I'm assuming there should be a tasty ale with grapes coming from them soon too!!