trübtest

Trübtest is a term used in German-language contexts to describe a test that assesses turbidity, or cloudiness, of a liquid sample. The test is used to evaluate how much suspended matter reduces transparency, which is important for process control, safety, and product quality.

Etymology: trüb means cloudy; test means test. In practice, "trübtest" may refer to both qualitative visual assessments and quantitative instrumental measurements of turbidity. In technical literature, it is often distinguished from colorimetric tests by focusing on scattered light rather than color.

Method: Quantitative trübtests use a turbidimeter or nephelometer to measure the scattering of light by suspended particles, yielding a turbidity value typically in NTU. Calibration uses standards such as Formazin or ASTM NTU references. Qualitative tests may use comparison cards against reference clouds or rely on simple visual inspection.

Applications: Water treatment and supply, wastewater monitoring, beverage and brewing, food processing, cosmetics, oil and chemical industries. It helps assess filtration efficiency, filtration process control, and product stability.

Standards and limitations: Turbidity measurements can be affected by color, dissolved substances, and particle size distribution. Temperature and sample handling influence results. Methods are covered by standardized protocols such as ISO 7027 and EPA turbidity methods, which specify measurement geometry and wavelengths. The term "trübtest" is not a single official method and usage varies by country and industry.