I normally thicken my liquid soaps with HEC (Hydroxyethel Cellulose) at a rate of 1% - 1.5%. HEC can be easy to use and leaves your soap crystal clear (assuming your formulation produces a clear soap). I have recently been introduced to HPMC (Hydroxypropyl Methycellulose) as a thickening agent as it is supposed to be easier to use than HEC. There are a few differences in how you use each one.
HEC (can be added before or after dilution)
- Mix with your solvent at room temperature with a whisk
- Add mixture to your liquid soap at room temperature
- Mix with solvent at room temperature with a whisk
- Add mixture to room temperature dilution water and whisk for 5 - 20 minutes to thoroughly disperse
- Add dilution water/HEC mixture to room temperature soap paste
- Use a whisk to blend in HEC mixture. Heat up soap. If mixture is added after dilution - stick blend when hot to fully distribute to avoid fish eyes, otherwise, allow soap paste to dilute as normal.
- Thickening is achieved as HEC solution is exposed to a higher Ph (as typical in liquid soap) and heat