- there are a variety of non sugar water soluble molecules, example northern/ wild grapes, current and grapefruit have a high percent acid, pear juice has sugar alcohol, gum Arabic has a polysaccharide, honey has higher sugars that don’t ferment, amino acids get incorporated into cells but don’t ferment, normal fermentations leave 1.5 to 2 gm/ liter of unusual reducing sugars as arabinose, xylose, pentodes, and if I am on the lab bench I could add lactose ( milk sugar) . . . . ie lots of molecules are water soluble and don’t ferment into alcohol.
- alcohol has a lower density than water, therefore the more alcohol produces lower density.
- some yeast products as glycerol are more dense therefore this would increase SG above 1.000
- salts are the standard lab method to calibrate a hydrometer, and of course every organic acid ion comes along with an alkali salt
The system is a mixture, it will vary from fermentation to fermentation. ,,,, >>>> the commercial way to say one has a legal label is to measure the ABV