Phenolphthalein PH Indicator

Choose Size

12ml plastic dropper bottle for easy use

Phenolphthalein is a liquid that can be applied, one drop at a time, to soap. It turns pink when it touches a base. The darker the shade of pink, the higher the pH reading. You won't get an exact pH value, but you will be able to tell, quickly and easily, how far along the pH scale your soap is. It can be used for bar soap, liquid soap, and cream soap.

What is an acid-base indicator?
An acid-base indicator is a weak acid or a weak base. Indicators have a very useful property - they change colour depending on the pH of the solution they are in. This colour change is not at a fixed pH, but rather, it occurs gradually over a range of pH values. This range is termed the colour change interval. Each pH indicator is defined by a useful pH range. For example Phenolphthalein changes from colourless at 8.2 to pink at 10.

The drops we sell consist of phenolphthalein in a solution of alcohol and water. Used for testing your handmade soap to make sure it's not too alkaline (or lye heavy). You could also use pH strips, but we think the drops are more economical and so much easier to use! You simply cut a small slice of soap and drop one drop of the 1% phenolphthalein onto it. Immediately the drops will answer the question if your soap is lye heavy (magenta pink) or okay to use (colourless).