Microorganisms have a higher density than the surrounding medium. After sufficient standing time, they settle to the bottom in high concentrations. The sample taken from this part of the medium represents the microbiological load of the total volume (qualitative). Foreign organisms in the industrial yeasts are primarily obligate beer-spoilage organisms (gram-positive and gram-negative anaerobes) and wild yeasts.
Cloudy beer samples with sediment
Microscopic examination of the sediment for obligate beer-spoilage organisms and wild yeasts by selective enrichment.