Fruit raising the SG

[z987k]

I've used fruit a few times before, but I've never know how much x amount of fruit raises the specific gravity. I think it's be cool if we could have a table of 1 lb of X fruit will raise the specific gravity X amount.
Now I know just plain fruit in water really doesn't add any sugar until it sits in the water for awhile or yeast get a hold of the sugars. But obviously it does raise the SG, but it seems impossible to measure it with a hydrometer.

 

[cclloyd]

I was wondering this as well - I boiled 3 lbs of blueberries in a wheat ale recently - the OG was right at the target (1.054) and the SG when I racked to secondary was 1.016 but it is still burping every 30 seconds or so after two weeks in secondary. Maybe the fruit sugars are more complex and take longer to ferment?

 

[z987k]

actually the fruit sugars are less complex. Maltose is a disaccharide comprising of two glucoses while fructose is a monosaccharide.

I believe the yeast have to break apart the maltose before converting into ethanol and C02, might be wrong on that though.

 

[david_42]

Most fruit runs 4-6% sugar. So, a pound of blackberries would add about an ounce of sugar while diluting the batch around 5%.

Net loss in SG.