Meaning and mechanism
Constant mass means that mass changes after repeated treatment and cooling fall within a specified limit.
Sample mass excluding container A is B−A; the mass lost on drying is B−C.
Relationships and conditions
(B−C)/(B−A)×100 is loss on drying; (C−A)/(B−A)×100 is the residue percentage.
Three cooled readings and two differences ≤0.0003 g are educational rules. The linked source has not been fully checked for current sample-specific conditions.
What to observe in the food simulation
Divide loss B−C by sample mass B−A. Remaining dry matter is not the numerator for moisture.
The 105°C and virtual times in food-edu-v1 are educational settings. Volatiles and decomposition can also cause loss, so loss on drying is not always pure water content. Use tongs for hot dishes.
Key relationships and symbols
Moisture (%) = (B − C)/(B − A) × 100
| Symbol | Meaning | Unit |
|---|---|---|
| A | Mass of empty container at constant mass | g |
| B | Mass including container before drying | g |
| C | Cooled mass including container after drying | g |
Worked food-analysis example
Do two close readings after cooling establish constant mass?
This model requires both differences in three consecutive readings to be at most 0.0003 g.
Common misconceptions
- Even stable mass may not distinguish volatile loss and thermal decomposition from water evaporation.