droogbasis

Droogbasis, or dry basis, is a term used to express the concentration of a substance relative to the dry matter of a sample, i.e., with all moisture removed. It is commonly used in chemistry, food science, agriculture, and nutrition to enable fair comparisons between samples that have different water contents.

On a dry basis, the mass of the sample includes only the dry matter, while moisture is excluded. If a sample has a moisture fraction w (where w is the water mass divided by the total sample mass) and a substance is measured as X percent by weight on an as-is basis, its value on a dry basis is X_db = X / (1 − w). For example, a sample weighing 100 g with 12 g of water and a nutrient content of 2.4 g per 100 g as-is has a dry-basis nutrient content of 2.4 / 0.88 ≈ 2.73%.

Applications include reporting nutrient contents, caloric values, or mineral concentrations in feed, crops, and foods where moisture varies. The dry basis is often indicated as db or as a dry matter basis (DMB) in lab reports.

Notes and cautions: moisture content is typically determined by drying the sample to constant weight at a standard temperature (commonly 105°C). Values on a dry basis assume complete moisture removal and may be affected by substance loss or degradation during drying; alternative standards may be used when appropriate.