What is emulsification?
Emulsification is the dispersion of oil into water as fine droplets held in suspension by surfactants. It is how a degreaser removes mineral oils, which cannot be saponified. The oil is lifted from the surface and carried in the bath until it is skimmed, filtered or the bath is changed.
Surfactant molecules have an oil-loving tail and a water-loving head. At an oil film they orient with tails into the oil and heads into the water, and the film breaks up into droplets each wrapped in a surfactant shell that prevents them recombining.
There is a design decision hidden here. A tightly emulsifying cleaner holds oil in suspension indefinitely — excellent for cleaning, terrible for bath life, because the oil never separates and the bath saturates. A demulsifying or split cleaner deliberately lets the oil break out and float, so it can be skimmed off and the bath runs for weeks longer.
Which you want depends on your equipment. A washer with a skimmer and coalescer wants a splitting cleaner. A simple soak tank with no oil removal wants a strong emulsifier and a planned change interval.
