FG beer vs wine

[Thomas1999]

Hi, why the final gravity of wine is much lower of the final gravity of beer? What influences this difference?

 

[DBhomebrew]

The sugars in fruit are all simple sugars, easily fermented by yeast.

Sugars from malt include larger sugars such as maltose, maltotriose, dextrins, etc. These are more or less nonfermentable depending on the yeast strain. This is reflected in each yeast's average attenuation stat.

 

[VikeMan]

Hi, why the final gravity of wine is much lower of the final gravity of beer? What influences this difference?

As @DBhomebrew said, the difference in fermentability between beer worts and wine musts is the sugar/dextrin profiles. A little more detail on fermentability of various sugars/dextrins:

- Glucose, a monosaccharide sugar that all brewer's Sacch yeast strains can use
- Fructose, a monosaccharide sugar that all brewer's Sacch yeast strains can use
- Sucrose, a disaccharide sugar that all brewer's Sacch yeast strains can use
- Maltose, a disaccharide sugar that virtually all brewer's Sacch yeast strains can use
- Maltotriose, a trisaccharide sugar that almost all brewer's Sacch yeast strains can use, but to varying degrees by strain
- Higher Dextrins, a group of low-ish weight carbs that are more complex than sugars and that most brewer's Sacch yeast strains cannot use (but some, i.e. "diastaticus" strains can use)

The sugars in Wine musts (i.e. grapes) are almost all glucose and fructose. Beer worts contain all of the sugars/dextrins listed above, in varied proportions.

ETA: Here's a link to an old presentation on attenuation (fermentability), that covers the above information and more:

Attenuation Factors Presentation (.PDF)

 

[Lefou]

Dextrins and complex carbohydrates that aren't initially present in the mash can be created by heat in the wort boiling process.
Kilned darker malts will have more of these complex carbs present than lighter base malts.