Winemaking taste of the wine. Brix (°Bx) is one measure of the soluble solids in the grape juice and represents not only the sugars but also includes many other soluble substances such as salts, acids and tannins, sometimes called total dissolved solids (TDS). Because sugar is the dominant compound in grape juice, these units are effectively a measure of sugar level. The level of sugar in the grapes determines the final alcohol content of the wine as well as indirect index of grape maturity. °Bx is measured in grams per hundred grams of solution, so 20 °Bx means that 100 grams
Phenolic content in wine into wine, most notably vanillin which adds vanilla aroma to wines. Most wine phenols are classified as secondary metabolites and were not thought to be active in the primary metabolism and function of the grapevine. However, there is evidence that in some plants flavonoids play a role as endogenous regulators of auxin transport. They are water-soluble and are usually secreted into the vacuole of the grapevine as glycosides. "Vitis vinifera" produces many phenolic compounds. There is a varietal effect on the relative composition. In red wine, up to 90% of the wine's phenolic content falls under the classification of flavonoids.