Frischmasse

Frischmasse is a German term that translates as "fresh mass" or "wet weight" and denotes the mass of a biological sample including its water content at the time of measurement. It is widely used in agriculture, ecology, forestry, food science and physiology to report yields, biomass and concentrations of constituents on a fresh-weight basis.

Measurement is normally made immediately after harvest or sampling to capture the natural water content; values are reported in grams or kilograms. Because water contributes substantially to Frischmasse, many studies also determine dry mass (Trockensubstanz) by oven drying a subsample to constant weight, allowing calculation of moisture content and conversion between fresh and dry bases. Typical drying protocols vary by material and purpose (commonly in the range of 60–105 °C), and methodological differences can affect comparability.

Applications of Frischmasse include reporting crop yields, estimating standing biomass in ecological surveys, expressing nutrient or metabolite concentrations per unit fresh weight, and assessing livestock feed. Advantages of using Frischmasse are ease and speed of measurement and relevance to handling and processing; limitations include sensitivity to hydration state, diurnal and seasonal variation, and potential weight loss during storage or transport.

Best practice in reporting recommends stating measurement conditions, moisture content or dry-mass equivalents when possible, and using consistent protocols to ensure that Frischmasse values are comparable across studies. In English-language literature, Frischmasse is commonly referred to as fresh weight (FW) or wet weight (WW).