Fig Concentrate Gravity Calculation

MikeScott

A quick sanity check on calculating the gravity contribution of the fig concentrate I'm planning on adding to a porter. Looking at the nutrition label of the concentrate, it contains 100g of sugar per 8 fluid ounces. I'm assuming I should use that number instead of the overall carbohydrates. This means that 16 oz (it's an 8oz container) would have 200g of sugar, and contribute .084 to a gallon of wort. Then I divide that .084 by the number of gallons and I get my overall gravity increase.
Is that right? School me!  

VikeMan

Fruit contains sugars and what I call "non-sugar carbs." Sugar is soluble and some portion of the non-sugar carbs are also soluble. Your linked product is a syrup, so my guess is that most or all of the carbs that made it to the final product are soluble.
For Original Gravity purposes, it may be better to assume that all of the carbs in the syrup affect gravity.
Using your original assumption of 200 grams of sugar (for 16 ounces of syrup)...
200 grams = 0.440925 lbs
0.440925 lbs x 46.21 Points per Pound = ~ 20 Points {not 84}
So you'd divide 20 points by the number of gallons of wort
Using all of the carbs...
320 grams = 0.705479 lbs
0.705479 lbs x 46.21 Points per Pound = ~ 33 points
So you'd divide 33 points by the number of gallons of wort
Note that the syrup will also add volume. The math above works for the number of gallons of finished wort (not the volume of wort before adding the syrup).

MikeScott

I'm glad I asked! Thanks for that, I appreciate it!