German wine the best vineyards in Germany are steep vineyards overlooking rivers, where mechanisation is impossible and a lot of manual labour is needed to produce the wine. Since it can be difficult to get ripe grapes in such a northernly location as Germany, the sugar maturity of grapes (must weight) as measured by the Oechsle scale have played a great role in Germany. German vintners on average crop their vineyards quite high, with yields averaging around 64-99 hl/ha, a high figure in international comparison. "New" crossings used for low-quality white wine commonly yield 150-200 hl/ha, while quality-conscious producers who strive to
Phenolic content in wine concentration in the skins of wine grapes. The accumulation in ripe berries of different concentrations of both bound and free resveratrols depends on the maturity level and is highly variable according to the genotype. Both red and white wine grape varieties contain resveratrol, but more frequent skin contact and maceration leads to red wines normally having ten times more resveratrol than white wines. Resveratrol produced by grape vines provides defense against microbes, and production can be further artificially stimulated by ultraviolet radiation. Grapevines in cool, damp regions with higher risk of grape diseases, such as Bordeaux and Burgundy, tend to