-
W/O Emulsions and how they differ
Hi Guys,
I am trying to formulate a W/O emulsion and wanted to get some more ideas on how the formulation process differs from O/W.
So far I have:
- W/O needs an electrolyte in the water (disperse) phase
- W/O needs low HLB emulsifiers
- W/O cannot have gums/rheology modifiers such as xanthan as water needs to disperse
- W/O generally needs polar oils (MCT, castor oil etc) and generally low content of other plant oils
- Add water phase slowly to oil phase
- W/O can have a higher water content when using special emulsifiers but it it mainly higher in oil %
I have a few questions:
- When should I emulsify? Should i start emulsifying when adding the water phase like O/W when both are at 75C? Or simply mix when adding water and then homogenise/emulsify when cooler (if so what temp)?
- O/W you can add a small amount of low HLB emulsifier to stop creaming - can i do the opposite with a W/O and add a small amount of high HLB emulsifier to allow higher HLB oils to be added and still be balanced? Or do i need to stick with low HLB emulsifiers only?
- Can a W/O product have a higher HLB than 6 or must be below 6? If it does, does this technically mean it is O/W?
If there’s anything I am missing, please let me know as i am having some trouble with W/O.
-
1 Reply
-
geepee said:Hi Guys,I am trying to formulate a W/O emulsion and wanted to get some more ideas on how the formulation process differs from O/W.
So far I have:
- W/O needs an electrolyte in the water (disperse) phase It usually helps
- W/O needs low HLB emulsifiers Not necessarily, only for ‘traditional’ emulsions
- W/O cannot have gums/rheology modifiers such as xanthan as water needs to disperse Sure they can and they help with stability
- W/O generally needs polar oils (MCT, castor oil etc) and generally low content of other plant oils No, not ‘need’ but polar oils (e.g. synthetic ester oils) help. Using hydrocarbons may require some tweaking (lower HLB, more salt…)
- Add water phase slowly to oil phase Usually yes
- W/O can have a higher water content when using special emulsifiers but it it mainly higher in oil % That’s the same believe as with o/w. Doesn’t need to but can.
I have a few questions:
- When should I emulsify? Should i start emulsifying when adding the water phase like O/W when both are at 75C? Or simply mix when adding water and then homogenise/emulsify when cooler (if so what temp)? Depends on the type of emulsion.
- O/W you can add a small amount of low HLB emulsifier to stop creaming - can i do the opposite with a W/O and add a small amount of high HLB emulsifier to allow higher HLB oils to be added and still be balanced? Or do i need to stick with low HLB emulsifiers only? No, blending is in theory fine. However, o/w emulsions are more tolerant and there’s totally other tricks needed to avoid problem X (because the phases are inversed).
- Can a W/O product have a higher HLB than 6 or must be below 6? If it does, does this technically mean it is O/W? It can have, thinking about HIPE gels, and no, HLB values don’t mean anything. They often don’t even apply… I stopped using that system, it gives me more headaches than good results.
If there’s anything I am missing, please let me know as i am having some trouble with W/O.
See within text
Log in to reply.