So I have a milk stout I’m doing using cherries and chocolate. Initial gravity was 1.063. When I moved it to secondary, the gravity was 1.020. I added 4 oz of cocoa nibs immeditately and 4 days later added 6 lbs of sweet cherry puree. The range of gravity for the puree alone is probably 1.020 based upon the label and it is now doing some further fermentation to convert the sugars in the cherries now.
With this addition, how do I adjust a final gravity reading to get an estimated abv for this? The recipe along should end up around 6.8% not accounting for the additions.