Author Topic: Accounting for fruit contribution to alcohol level  (Read 1519 times)

Offline rbowers

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Accounting for fruit contribution to alcohol level
« on: May 12, 2012, 02:41:56 PM »
For my upcoming raspberry wheat recipe I plan to secondary the beer on top of a raspberry puree for 2-3 weeks.  Likely going to use 3lbs.  Is there a way (or a reason) to account for the fermentation of raspberry sugars contribution to the alcohol level or is it negligible?

Online Jimmy K

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Re: Accounting for fruit contribution to alcohol level
« Reply #1 on: May 12, 2012, 02:48:28 PM »
It would require math.

Fruit contributes both sugars and volume too complicate that. I think it is often a wash.
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Offline tschmidlin

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Re: Accounting for fruit contribution to alcohol level
« Reply #2 on: May 12, 2012, 10:59:30 PM »
You can take a small amount of the puree and mix it with a measured amount of water, take the OG and then calculate the OG of the puree itself.  From there you can calculate what the new OG of the beer will be.
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Offline nateo

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Re: Accounting for fruit contribution to alcohol level
« Reply #3 on: May 13, 2012, 08:51:47 AM »
It would require math.

Fruit contributes both sugars and volume too complicate that. I think it is often a wash.

I would bet fruit would usually lower the alcohol, since fruit is mostly water with a bit of sugar.
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Offline bonjour

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Re: Accounting for fruit contribution to alcohol level
« Reply #4 on: May 13, 2012, 09:09:15 AM »
Beer Smith has a grain addition of fruit based on the US average brix (% sugar, ) of the fruit.

Bottom line, unless your wort is pushing 100% fruit very little impact

Raspberries have an average potential of 5 pppg so you are adding 3lbs* 5 pppg = 15 gravity points, so for the same volume in a 5 gallon batch your OG will go up 15/5 = .003,  This will increase abv by about .4%abv
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Offline kylekohlmorgen

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Re: Accounting for fruit contribution to alcohol level
« Reply #5 on: May 14, 2012, 07:39:23 AM »
I am doing the same thing now with blackberries, so this is helpful information!

The volume of the puree is important to account for. If you're going from a 6.5 gal carboy to a 5 gal, make sure you have enough room for the fruit and a bit of headspace for another (albeit small) fermentation. I used fermcap-S because the 3068 I used can be a very foamy fermenter!
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Offline trickydick

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Re: Accounting for fruit contribution to alcohol level
« Reply #6 on: May 07, 2014, 07:34:20 AM »
Beer Smith has a grain addition of fruit based on the US average brix (% sugar, ) of the fruit.

Bottom line, unless your wort is pushing 100% fruit very little impact

Raspberries have an average potential of 5 pppg so you are adding 3lbs* 5 pppg = 15 gravity points, so for the same volume in a 5 gallon batch your OG will go up 15/5 = .003,  This will increase abv by about .4%abv

Necro post, apologies.

Been trying to find answer for this myself.  I cannot find the grain entry in BS you mentioned.  Where did you find the average potential pppg of raspberries, and do you have a list for other fruits?  I am curious if fresh vs puréed fruit has different pppg value due to cell wall breakdown.

I notice that the displacement or volume of the fruit or purée has not been accounted for.  I think there is a complicated way to calculate this as I have seen on Belgian candi syrup packaging. 

I looking for pppg for blueberries,rhubarb, and white fleshed peaches if you happen to know the pppg. 

Thanks

TD