Quote:
Originally Posted by goofiefoot
Ok, so I found that each can of cherries has 33 grams of sugars. I used 10 cans, so this gives me 330 grams total sugars. I am adding this to a solution that already contains a beer with a gravity of 1.012 and ABV of 6.6%
How does one calculate the gravity that the cherries add to the 5 gallons of beer to come up with the OG2 from Jacob's equation?

1 lb of sugar = 454 grams = 46 gravity points.
330 grams of sugar = 33 gravity points
Your OG was 1.062 (I think that is what you said).
I assume the volume you are working with is 5 gallons (the volume in the fermenter before adding the cherries).
Effective OG = (62*5 + 33)/final volume.
Lets assume the 10 cans total 1 gallon (to keep it simple)
Effective OG = (62*5 + 33)/6 = (310+33)/6 = 343/6 = 57. The effective gravity would be 1.057 .... yes, lower than you started with.
To get the actual gravity after addition of the fruit, you would do the same calculation replacing the 62 with 12 (gravity before adding sugars was 1.012). Using the same volumes assumed before, gravity = (12*5+33)/6 = 93/6 = 15.5, or gravity = 1.016.