ABV contributions of Fruit

[Synovia]

I just finished brewing a light ale and pitched yeast today. I am planning on adding about 40 Oz of frozen raspberry. How do I go about determining final ABV of the beer?


Is there any good way to determine the sugar contribution of fruit?

 

[RogerMcAllen]

You could look it up in the FDA database:
http://www.nal.usda.gov/fnic/foodcomp/search/

I don't know how to figure out efficiency, but that should give you a pretty good high end.

 

[Arneba28]

Of if you want to do this from scratch. you blend one pound of berries and mix it with one gallon of water. Put the berries in a fine cloth bag and let it boil just for a minute. Then squeeze the bejesus out of it and keep dunking it in the hot water. Cool it and take an SG reading. Thats your SG per pound of whatever fruit you want.

 

[david_42]

The sugars from fruit will ferment 100%, but most fruits don't have much sugar in them. Raspberries run around 4-5% by weight so 40 ounces would be 2 ounces of sugar and add less than 0.1%. Juice, of course, runs higher.

 

[Ysgard]

Does Pectin break down into sugar with Pectic Enzyme?

 

[Synovia]

The sugars from fruit will ferment 100%, but most fruits don't have much sugar in them. Raspberries run around 4-5% by weight so 40 ounces would be 2 ounces of sugar and add less than 0.1%. Juice, of course, runs higher.

I don't doubt you, but why does it seem like people have so many issues with blow-offs with fruit beers?

 

[Brewmasters Warehouse]

I don't doubt you, but why does it seem like people have so many issues with blow-offs with fruit beers?

I think that blow offs with fruit beers has a lot more to do with the yeast strain being used then the fruit itself. A lot of fruit beers use wheat yeast strains that are known to aggressively produce krausen.

 

[MgMt_Home_Brew]

I don't doubt you, but why does it seem like people have so many issues with blow-offs with fruit beers?

Also I feel like some of the people I have talked to put it in a secondary 5 gallon carboy and didn't expect much of anything to happen. Then with no headspace they quickly relized they would need a blowoff hose.

 

[944play]

Sugar and Acid Content in Fruit

 

[david_42]

Although there isn't much sugar in fruit, it is mostly fructose and will ferment very rapidly. Also, it doesn't take much skin or pulp to plug an airlock.

 

[amercuric]

Does Pectin break down into sugar with Pectic Enzyme?

I can't answer this question directly as I'm not 100% sure, but it interested me and here's what I found:

"Pectic enzyme" will depolymerize pectin and serve as a clarifying agent to a beverage clouded by the action of pectin. Pectin is a heteropolysaccharide (polymer of different sugar molecules). Some fungi (including yeasts) are known to secrete pectinases which depolymerize pectin by hydrolysis of certain glycocidic linkages. Whether the chopping up of the pectin molecule results in fermentable mono, di, and trisaccharides is unkown to me. Although it certainly would make sense if it did.

If you want an answer: probably not. Some other enzyme would be responsible for that.