In the previous post about emulsifiers we talked about their HLB which, at the end of the day, only tells us wether an emulsifier is more lipophilic or more hydrophilic.
What we, more importantly, need to know about our emulsifier is
– how to use it (hot or cold process)
– and at which percentage.
This is not same for every emulsifier. Even with the same HLB, the ability of an emulsifier can be totally different (and therefore we might need to add to our cream more or less of it).
These information we can collect easily in the moment we purchase our emulsifier: who sells them know the percentage of use and usually posts it on the page of the product (if it is not written there, you could always send them an e-mail and ask for more details about their product. If they don’t know or don’t reply… well, change supplier and buy from a well informed one 😀 ).
However I have decided to put together a small guideline about emulsifiers.
The biggest difference is wether the emulsifier has to be used in hot process or cold process.
An emulsifier which needs to be heated up to 70° is usually solid, normally sold in pearls and his ability to emulsify is only at 70°C. If the two phases we are trying to emulsify do not reach this temperature… well, the emulsion will separate soon enough. So bear in mind to properly check the temperature of your two phases before you mix them (you don’t want to waste precious ingredients nor time, do you? 😀 ).
Since the highest number of emulsifiers work at 70°C, you have to simply follow the process which I already explained in the beginning: you heat up the two phases, you pour the phase B into the phase A and mix with an immersion mixer, once it looks emulsified very well you keep stirring with a spatula until the lotion cools down completely and eventually add your phase C.
There is an huge number of these emulsifiers.
Always remember that these emulsifiers can be more lipophilic or more hydrophilic… or can even be self-emulsifying (which means they already contain both lipophilic and hydrophilic emulsifiers) so always check their composition to find out if they need a co-emulsifier or not (you can, once again, find this specific information from the website where you order your supplies!).
Just to make an example of the two most easily found emulsifiers:
– Methyl glucose sesquistearate – needs to be used at 3%, needs to be heated up to 70°C to work and is more hydrophilic so it needs a co-emulsifier which will be lipophilic (for instance cetyl-alcohol at 1% will do).
– Montanov 68 – this is a self-emulsifier. If you read its composition it already contains both the lipophilic and the hydrophilic emulsifiers: Cetaryl alcohol,Cetearyl Glucoside. It is usually added at 4% to a cream and needs to be heated up to 70°C.
Even if it might sound more difficult, having to mix your own two emulsifiers gives you better results in your cream (at least once you get the grip of it and realize what is the effect of each emulsifier in the final lotion).
If you want to follow a good advice, you should make different experiments with just water (gelled water) and a very cheap oil in a fixed amount and different emulsifiers, if you do this, you will be able to experience the different effect each emulsifier gives to your cream. This is a very important experiment if you want to be aware of which emulsifier does what… (and in the moment you decide to formulate a cream these notions will be very important!).
The “no heat” emulsifiers, instead, are usually liquid (normally very dense). They simply need to be added to phase B and, unless you are using rather difficult active ingredients (meaning that these active ingredients should be added alone in the end of the process), the phase A might contain also the phase C.
Once again you simply pour phase B into phase A and you mix with your immersion mixer until the lotion is formed.
Just one note: usually creams made with “no heat” emulsifiers are not very emollient and rich. This is due to the fact that, since the emulsifier cannot be heated up, you cannot use butters in your cream.
However SOME “no heat” emulsifiers (that, let me repeat again, just mean that the emulsifier will have emulsifying power even at normal temperature) DO bear heating. If you use such an emulsifier you can heat up the phase B in order to melt the butters (let’s say shea butter for example… which doesn’t need a high temperature to melt!) and then you can combine phase B to phase A and normally create your lotion.
If you want to do so, you should be able to get information about your “no heat” emulsifier, once again, right from your supplier. 🙂
This is all about the emulsifiers.
Let me know if you have any more specific questions about them.
Have a great day! 😀