Scale used in Germany to indicate the ripeness of grapes. Developed in the nineteenth century by the physicist Ferdinand Oechsle, Oechsle (ERKS-la) measures the weight of the grape juice or must. Since the contents of the must are primarily sugar and acids, the must weight is an indication of ripeness. According to traditional German law, ripeness categories are based on Oechsle levels that are specified for each grape variety and wine region (meaning they can change region to region). For example, for a riesling wine in the Mosel to be considered a spätlese, it must have 76 degrees Oechsle; in the Rheingau, a riesling must have 85 degrees Oechsle to be a spätlese. These adjustable levels reflect the fact that in some very cold regions like the Mosel, ripeness is harder to achieve.