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 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.