Oechsle, scale of measuring grape sugars, and therefore grape ripeness, based on the density of grape juice. Grape juice with a specific gravity of 1.075 is said to be 75 °Oechsle. This is the system used in Germany and it has its origins in a system of weighing grape must developed first by the Württemberg scientist J. J. Reuss, but much refined in the 1830s by the Pforzheim physicist Ferdinand Oechsle (see german history).
Like other scales used elsewhere (see baumé and brix), it can be measured with a suitably calibrated refractometer or hydrometer. A similar scale, devised at klosterneuburg, is used in Austria.