Potential abv

[Jim97]

Hey i was wondering how to calculate amount of suger in fruits from the nutritional fact on the bag are the carbohydrates and sugers added together for the total fermentable sugers or is it only the suger that is broken down by yeast meaning that the carbohydrate content is irrelevant to the potential abv

 

[VikeMan]

Well... the sugars will be fermented. As you noticed, there's also a total carbohydrate number. Subtracting the sugars from the total carbs will give you the unfermentable carbs. But wait, there's more! Some of those unfermentable carbs will be soluble, and will affect the effective OG and FG of your wort/beer.

If you are thinking of adding fruit to a beer, there's a spreadsheet at this link called FruitCalc that you might find useful:
http://sonsofalchemy.org/library/

 

[Jim97]

Thankyou that helps a great deal so basically i have to add up the carbs and the sugers to get a rough idea of the total fermentable sugers in the fruit

 

[VikeMan]

Thankyou that helps a great deal so basically i have to add up the carbs and the sugers to get a rough idea of the total fermentable sugers in the fruit

No. The only part that's fermentable is the sugars. The rest of the carbs are not fermentable. But some of those non-sugar carbs will dissolve, thus affecting OG and FG. And some of those non-sugar carb will not even dissolve.

 

[Jim97]

Ok so for example if i use the mango available to me it has 11.2g of suger per 100g and 11.6gram of carbs per 100g so that means there is 0.4g of unfermentable sugers in said mango so dose that mean that the total fermentable suger is 11.2 grams meaning that if i want to know the total fermentable suger content i just have calculate that from the suger percentage only meaning the carbs are irrelevant in this case unless i want to know the unfermentable sugers

 

[VikeMan]

If you want to compute the impact to ABV, you can pretty much safely ignore the unfermentable carbs. I say "pretty much" because in some cases, there are significant amounts of it, and the portion that dissolves can affect ABV because it affects volume slightly. But even then, it's a pretty small impact.

Much more important though, is the fruit's water content. Many fruits can actually decrease the ABV of a beer, depending on the type of fruit and the characteristics of the base beer.

 

[Jim97]

If i ignore the unfermentable carbs do i add the carb content and suger content together or just use the provided suger content thats in the bag sorry its still confusing

 

[VikeMan]

If i ignore the unfermentable carbs do i add the carb content and suger content together or just use the provided suger content thats in the bag sorry its still confusing

Yes, if ignoring unfermentable carbs, just use the sugar content and not the "carbohydrates" number. But don't forget about the water. You can't just add the sugar to your beer and compute ABV.