Calculating amount of space fruit takes up

[Rob2010SS]

Anyone know of a way to estimate how much space in a fermenter a certain amount of fruit will take up? I have 17.5 - 18 gallons of beer in a half barrel unitank. I'm looking at adding AT LEAST 18 - 20lbs of fruit.

I don't think I have a choice and I think I'm going to have to split the batch to another fermenter but before I go that route, I thought I'd ask to see if there's a way to estimate the displacement from the fruit.

 

[day_trippr]

I have no idea if there's any consistency wrt weight vs volume across the world of fruit one would brew with, but these two carboys were holding 4.5 pounds of frozen raspberries pureed with one cup of hibiscus tea each. They're just over the half gallon line, so discounting the cup of tea it I'd make it roughly a pint per pound...

Cheers!

 

[2bluewagons]

Fruit is pretty much water, yeah? So a pound per pint is probably as close as you're going to get.

 

[Vale71]

Most fruit is slightly buoyant and will float. As a matter of fact water is the preferred medium of transport for fruit in processing plants as it tends not to damage it. I would take about 0.9 times the density of water as good starting value.

 

[Rob2010SS]

So based on what has been said, I'd say it's safe to assume that 20lbs of fruit will take up 2.5gal of fermenter space. Looks like I'm splitting the batch!

Thanks for the input here guys/gals.