Sg after adding cherries

[EVILEMRE]

Anyone know how to calculate a final gravity after adding cherries when racking into a secondary?
My original gravity was 1.070. After a week in the primary it was at 1.018. I racked it into a secondary onto 5 lbs of fresh cherries. Puréed if you must know. Now how do I calculate my final gravity after an addition like that?

 

[ong]

Take a hydrometer reading after stirring gently? Alternatively, look at the nutritional information on a can of cherry puree, and back out the sugars from the grams carbohydrate per 100g serving.


Sent from my iPhone using Home Brew

 

[Osedax]

Figure out the gravity of the fruit. If it is above 1.070 SG then you gained alcohol and if it is below, you probably lost some. It is most likely a miniscule amount either way.

Here is a calculation to help but, it doesn't come through in text well:

Effective gravity= ((volume of beer in gallons×OG×8.35)×Original °P+(weight of fruit in lbs×°P of fruit))/((volume of beer in gallons×OG×8.35)+weight of fruit))

You will need both specific gravity and degrees plato. A simple converting calculator can be found online. This formula was taken directly from the book American Sour Beers.