I'm currently fermenting a gluten-free strawberry IPA. The wort went into the fermenter with an OG of 1.050 (a little lower than I'd aimed for, but non-traditional grains can be less predictable). Three days later, the yeast had been working, and the gravity was down to 1.021. I stirred in a few pounds of strawberries I'd pureed in the blender, and the gravity climbed to 1.033, presumably due to the addition of sugars from the fruit. My question is about how to calculate the ABV when I check the final gravity before bottling tomorrow. My thought was to calculate the amount of alcohol created during the fermentation prior to adding the puree -- 1.050 to 1.021 --> ABV=3.81% -- and add it to the calculated alcohol from after the addition of strawberries to the final gravity -- 1.033 to (let's say) 1.015 --> 1.58%). If that approach is correct, my beer will have an ABV = 3.81 + 1.59 = 5.4%. So, is that an accurate way to calculate my ABV? Or am I completely off track, having scuttled any hope of accurate calculation when I added the strawberries?