Turbidity

The cloudiness or haziness of a solution — the optical effect of finely suspended matter such as proteins, polysaccharides, microorganisms, or mineral particles scattering light. In beverages, unexpected turbidity flags faults: protein–polyphenol haze in beer, microbial spoilage in juices, poor filtration in water. Yet controlled turbidity is desirable in products like cloudy apple juice or wheat beer. Analysts quantify turbidity by turbidimetry or nephelometry in NTU units, and it stands as a routine specification in water, beverage, and ingredient quality control.