how do I calculators FG after adding fruit or sugar in secondary?

[vera]

I'm getting ready to add 4 lbs of fruit to my secondary. I brewed an American Wheat. Let's say my FG on the wheat is currently 1.010. I have a Five gallon batch. How will adding 4lbs of fruit effect the gravity? There's got to be a formula. Eventually I would like to add sugars to my secondary for my Belgiums. How does one account for that? How else would one figure out the ABV, if you've changed all your variables with fermentable additions?

 

[vera]

Can anybody help with this?

 

[sweetcell]

for late sugar additions, treat them just as if they were added to the boil. a pound of sugar is going to turn into the same amount of alcohol & CO2 regardless of when it's added. well, this isn't 100% true - if the alcohol level in the beer is above the tolerance of the yeast, they will have died out so there won't be anything there to ferment the newly added sugar. but assuming you're under the yeast's max ABV, you'll be fine.

no idea how to calculate the impact of fruit, but there must be something out there. just gotta figure out how much fermentable sugar is in there.

 

[DannPM]

Fruit, even of the same variety, has widely different water percentages. Unless you know how much water is in the fruit you won't know the exact abv impact.

A very rough rule of thumb is that it adds nothing due to the water content of the fruit.

 

[vera]

Thanks all!