Pure water is used in the make-up of liquid soap and therefore reverse osmosis (RO) or deionised (DI) water quality is required depending on the desired result.
When making lotions and shampoos, muslin was traditionally used as filtration, however this is replaced by bag filtration in production as a high surface area option with greater efficiency. Bag filtration is used in the early stages to remove large deposits of unmixed product and anything that could produce an uneven finish. These are typically housed in stainless steel housings due to the flows, pressures and cleaning regimes involved.
