What Does Percent Solids Mean?

The rest is mainly water. A laboratory dries a measured sample and compares dry mass with wet mass. The standard total solids test dries the sample at 103 °C to 105 °C to a constant weight. The test requires suitable equipment, time, and a documented method. Burning the dried solids at 550 °C shows the volatile solids, the organic part that digestion breaks down. A cake that feels firm is not automatically high in measured solids.

Two samples look alike, but the lab reports different dry-solids results. The operator checks sample time, press settings, and whether both samples represent steady operation.

Use the measured value when reporting, calculating loads, or comparing dewatering runs. Do not substitute a visual estimate.

Percent solids is a fraction of the wet sample's mass. It does not tell how much of the solids the press removed. It tells what share of the tested wet material was dry matter; the math box shows an example. Keep that meaning clear when reporting performance.

Key point: Percent solids compares dry mass with wet mass. A result of 20 percent means the wet material is about one-fifth dry matter.