Calculations for Fruit Beers

[nealmc]

My next beer is going to be a Wheat beer - something close to a Dunkelweizen, but SWMBO has requested that a fruit be added. She suggested raspberries. I have read the Razz Buried Thread, and will probably come close to something like this, but AG.

I was wondering if there are any calculations out there to figure the amount of fermentables in different fruits. I would like to be able to calculate the final ABV% and so on. I am planning on racking on top of the pasturized fruit in the secondary, so I suppose I could take a gravity measurement of the fruit (off the scale?) before I add it, but this would require me knowing the fraction of the total sugars in the fruit that are fermentable in order to calculate the total amount of sugars that have been consumed by the yeast. I am guessing that there is a fairly well defined fraction somewhere for grapes, but what about for other fruits?

 

[david_42]

Fruits are mostly water and have few fermentables, maybe 5-10% of weight. So, two pounds of berries would be 1-3 ounces of sugar.

 

[nealmc]

I did a little bit more researching and found this table of exact sugar content of a bunch of different fruits and fruit juices, broken down by type of sugar. I hope this helps fellow OCD number crunchers. Looks like you were right on, david_42. Thanks!

 

[magno]

Thats awesome, Ive wondered about the existence of just such a chart.

- magno

 

[feedthebear]

Rule of Thumb: 1.008 to 1.010 per pound per gallon.

 

[jayhoz]

Rule of Thumb: 1.008 to 1.010 per pound per gallon.

Sorry to drag up this old thread.......

If you were formulating a recipe with a target OG of 1.049 would you take into account the gravity contribution of the fruit? If I was to add 5lbs of fruit to a 5 gallon batch would I shoot for a post boil gravity of 1.008 to 1.010 lower (ie 1.040)?

Second question: I am trying to create a Pete's Wicked Strawberry Blonde clone. From their website (http://peteswicked.com/beerlist/nf_strawberry_spec.html) they claim an OG of 1.049 (12.05 degrees plato). Do you think this OG accounts for the fruit fermentables or should I shoot for 1.049 post boil and not worry about the fruit sugars?

 

[feedthebear]

The fruit beer recipe's that I have seen, typically the O.G. and the ABV are given without taking the fruit into account.

I would brew it targeting an O.G. of 1.049 on a 5.5 gallon batch without considering the fruit sugars. I'd use the extra 0.5 gallons of water because you are going to leave more beer behind than normal when you rack off the fruit. And if you put the fruit in the secondary and rack to a tertiary before bottling, you'll leave even more behind.

The difference in ABV for an O.G. of 1.049 and one of 1.059 is only 0.75%. Its not a lot to be terribly worried about, IMO.