Establish constant masses for the empty container and three samples, then calculate loss from the final observed masses.
Food Lab · moisture determination
An educational model. It does not replace actual test conditions or safety procedures.
Loss on drying and constant mass
Mass lost and mass remaining
Moisture determination expresses the mass lost under specified drying conditions as a percentage of sample mass.
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.
(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.
Even stable mass may not distinguish volatile loss and thermal decomposition from water evaporation.
An independent educational simulation. Not affiliated with or endorsed by HRD Korea, Q-net or MFDS. Virtual results do not establish food safety or guarantee exam success.
Food Lab · Gravimetric analysis / principles and inquiry
Moisture determination guide
Distinguish the empty dish from the sample and calculate loss on drying from cooled masses.
How does it work?
Divide loss B−C by sample mass B−A. Remaining dry matter is not the numerator for moisture.
Key relationship
Moisture (%) = (B − C)/(B − A) × 100
Try this investigation
Dry, cool and weigh the empty dish six times to establish A, then record B with the sample.
Dry each of three samples to constant mass; retain the last observed C and every cycle record.
Keep normal records and compare an invalid case where moisture uptake increases C.
Interpreting your results
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.
Assumptions and limitations
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.
