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 the vanilla notes in wines that have been aged in oak. Trace amounts of vanillin are found naturally in grapes, but they are most prominent in the lignin structure of oak barrels. Newer barrels will impart more vanillin, with the concentration present decreasing with each subsequent usage. Oak barrel will add compounds such as vanillin and hydrolysable tannins (ellagitannins). The hydrolyzable tannins present in oak are derived from lignin structures in the wood. They help protect the wine from oxidation and reduction. 4-Ethylphenol and 4-ethylguaiacol are produced during ageing of red wine in oak barrels that are infected by brettanomyces