The effectiveness of solid impurity separation in milk depends on its viscosity, with lower viscosity improving separation. Therefore, warm milk (around 50°C) is preferred for optimal clarification. However, in areas where raw milk quality is uncertain, clarification can also be done with cold milk upon arrival at the dairy. In whey processing, clarifiers remove cheese fines before skimming, increasing cream separation efficiency and fat recovery.  A low residual fat content aids the performance of membrane filtration units or evaporators that follow the process.