What does beading of water droplets indicate after a bulk tank is washed and rinsed?

Beading of water droplets on the surface of a bulk tank after it has been washed and rinsed is an indication of the presence of fat residue. When there is fat on the surface, the water droplets tend to bead up rather than spread out. This is due to the hydrophobic nature of fat, which repels water and causes the droplets to maintain a spherical shape.

In a properly cleaned tank, water droplets should spread out and form a thin film across the surface, indicating that the tank is free of residues including fats, proteins, and other contaminants. The beading effect serves as a visual cue that some cleaning agents may not have completely removed the residues, which is critical in maintaining hygiene standards for dairy production. Therefore, noticing beading is an important aspect of evaluating the cleanliness of the bulk tank.