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
Brix prism; the result is observed through an eyepiece. The critical angle (the angle beyond which light is totally reflected back into the sample) is a function of the refractive index and the operator detects this critical angle by noting where a dark-bright boundary falls on an engraved scale. The scale can be calibrated in Brix or refractive index. Often the prism mount contains a thermometer which can be used to correct to 20 °C in situations where measurement cannot be made at exactly that temperature. These instruments are available in bench and handheld versions. Digital refractometers also find the critical