The phrase represents the measurement of all solids that are dissolved in a solution, typically water. These solids can include minerals, salts, sugars, and other organic compounds. For example, in fruit juice, the level indicates the amount of sugars present, which contributes significantly to the sweetness and overall quality.
Determining the quantity of dissolved materials is crucial in various fields, from agriculture and food production to environmental monitoring. In agriculture, it helps assess fruit maturity and predict harvest time. In water treatment, it is an indicator of water quality and the effectiveness of purification processes. Historically, methods for determining the amount of dissolved substances have evolved from simple evaporation techniques to sophisticated refractometry.