Riesling grapes are naturally very high in acid, and the cool, northern climate of Germany means this ripping acid stays in the grapes even into the fall harvest season. So winemakers let the fermentations stop before the wine is completely dry, retaining a little sweetness in order to strike balance in the wine.
Oxygenation refers to the process of adding oxygen to the body system. There is no way to reliably measure arterial oxygenation via clinical signs alone. Cyanosis, pallor and other physical findings are not reliable.
Hydrogenation is a chemical process in which hydrogen gas is bubbled through a liquid oil in the presence of a catalyst, often a reactive metal such as platinum or nickel. The resulting reaction forces unsaturated fatty acids to accept additional hydrogen atoms and become at least partially saturated.