Sugar content of Fruit

[winemanden]

Just a query. Was that attachment I uploaded readable? The reason I am asking is that looking through my old wine recipes I came across a page I copied from Bravery's Amateur Winemaker magazine. It's a graph showing how much residual sugar is left in a wine. If the previous chart was readable I can upload this one.

 

[winemaker81]

@winemanden, I had no problem downloading and reading the document.

 

[Rice_Guy]

The specific gravity is giving a reading of total “dry extract” in the juice. For the purpose of grapes it gives a fairly consistent percentage of the juice (yes we know there is error between a wet year, a dry year, ice wine, old vines, fertilized vines, etc). Gravity readings are so easy and reliable so as @Scooter68 says they give excellent relative information.

If I want the actual number as for a legal nutrition statement I would have a lab run the fehling test for sugar content. Looking at cross species juices/ pulps there can be significant difference from gravity.

Bottom line these charts give excellent relative information - Apples vs Bananas vs Grapes vs Strawberries etc. We still need to rely on an SG reading for real data because of varying fruit ripeness, seasonal variations and varietal differences.
These charts can give us pretty good ideas of how much sugar we can expect to need to add when we do a batch from any given fruit vs other fruits we've used.

 

[winemanden]

I hope you're able to read this OK.
The solid grid is the initial sugar in 1 gallon and the final gravity. The dotted grid superimposed on top is the alcohol and the residual sugar. Where the two grids coincide gives the alcohol and residual sugar in your wine.