wetbasis

Wet basis refers to a way of expressing moisture content as the ratio of the mass of water in a sample to the total mass of the sample (water plus solids). It is commonly used in fields such as food science, agriculture, soil science, and materials processing. The moisture content on a wet basis is typically given as a fraction or a percentage.

Calculation is straightforward: let Mw be the mass of water in the sample and Ms the mass of dry solids. The total mass Mt equals Mw plus Ms. The wet basis moisture content is wwb = Mw / Mt, with %wb = 100 × Mw / Mt. In practice, Mw can be found from the loss of mass during drying, assuming volatile losses are negligible.

Wet basis moisture is related to moisture content on a dry basis (mdb), which is defined as the mass of water divided by the mass of dry solids (mdb = Mw / Ms). The two bases are connected by wwb = mdB / (1 + mdB) or mdB = wwb / (1 − wwb). This relationship allows conversion between the two conventions depending on which basis is used in a report or model.

Applications and interpretation: The wb basis is intuitive for processes where total product mass is important, such as mixing, packaging, or shipping. It can be more sensitive to mass changes during processing than the dry basis. Common measurement involves oven drying to constant weight to determine Mw and Ms, with standards often specifying methods and temperatures for accuracy.