I have the same question about predicting final gravity and ABV from fruit additions, so that I can plan my mash and pick a target for the initial grain gravity. I'm planning on adding a large amount of fruit. I wished the picking could have been closer to the brewing so I wouldn't have had to freeze the fruit so as to retain the natural terroir for a sour brew. At any rate, I will check out your link. The last time I did a fruit beer it was the raspberry stout recipe from TNCJOHB and I that was about 8 years ago and I don't recall what I did with the fruit, nor if there was visible airlock activity.
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Interesting article. Unfortunately no help for me, I think that the fruit, if puréed will be highly fermentable, perhaps as much as 97%, on a guess. I think I may consider fruit equivalent to sugar multiplied by 97% in terms of points per pound per gallon, unless anyone else has a better method. I hear at howtomakemead.com or some similar site there is a calculator, but I am not sure about it accuracy.