Phenolphthalein
A colourless liquid. Used to test soap for excess lye. Will turn pink or fuchsia in the presence of excess lye. It is the degree of pink that determines how alkaline your soap is. If a drop applied to the middle of a soap cutting turns deep pink or fuchsia then the soap should not be used on the skin. This soap however is great for the house and or laundry. If the drop stays clear or turns just the lightest shade of transparent pink then your soap should be fine.
