Definition - What does Non-Flavonoid mean?
In the context of the compound structure of wine grapes, Non-Flavonoids are phenolic compounds with variable structures, that contribute to specific characteristics in wine grapes. The two main classes of non-flavonoids found in wine grapes are the stilbenes and the hydroxycinnamates. The non-flavonoids are found primarily in the flesh of the grape berry.
WineFrog explains Non-Flavonoid
Phenolic compounds in wine contribute specific characteristics to wine while also creating specific flavors and aromas when the complex interactions take place in wine during fermentation and wine-making. While wine grape berries contain non-flavonoids, they can also be introduced to wine through oak barrel aging; non-flavonoids contribute to the antioxidant properties of wine grapes particularly in the form of reservatol, which is a stilbene non-flavonoid.
Reservatol is known to protect against cell dysfunction and death. The hydroxycinnamates non-flavonoids in grapes are potent antioxidants, but have little to no sensory impact in wine, though they are associated with the presence of brown pigment when allowed to oxidize. Ellagitannins and vanillin are the non-flavonoid introduced to wine through the addition of oak chips or oak barrel aging. Ellagitannins contribute to astringency and while they are often compared with tannins, they express more bitterness, while vanillin contributes a vanilla aroma and flavor to wine.