Making creams with Olivem 1000 – a guide for new formulators

Introduction to Olivem 1000

 

I’m not a technical writer and so this article will not pass muster in any kind of technical or scientific publications: rather, this article is simply an explanation of how, after several years’ experience of working with Olivem 1000, and countless batches of creams made, I’ve come to understand how to formulate with this emulsifier for best results.
Bear in mind that along the way I’ve had many failed batches: but I’ve probably learned more about working with Olivem – which ingredients to avoid for instance – from the mistakes than the successes.
I thought about including lots of technical information in this piece but then realised that you don’t really need to know about all that – it’s not going to make the creams you make any better – instead I decided to dive in and explain just how to work with it.

 

But I will mention that Olivem 1000 is different to basic emulsifiers such as the old stalwart – Emulsifying Wax (Cetearyl Alcohol and Polysorbate 60 – though there are variants of Emulsifying Wax). The tried and tested Emulsifying Wax is robust and reliable enough that it is almost fool proof and you could incorporate pretty much any ingredient into an Emulsifying Wax based cream. And the process was simple – blend the heated water phase with the heated oil phase – whizz for a minute with a stick blender and then leave to cool.

Olivem 1000 is a little trickier – but not difficult – to work with. You just need to pay a little more attention to it. And the extra effort is worth it because Olivem 1000 is a superior emulsifier to Emulsifying Wax – not only does it have a better skin feel, it imparts much improved skin moisturisation – an essential quality for any moisturising cream!
So, let’s start off with the basics

How emulsions work

An emulsion (the basis of your cream) is a blend of oil and water with an agent (the emulsifier) which allows oil and water, which normally repel each other, to blend. As a very general rule of thumb, bearing in mind you are allowed a fair amount of deviation from this rule, the ratio of water, oil, and emulsifier, is generally in the ratio of 80:15:5. We call the first part the water phase and the second part the oil phase. The water phase includes the actual water and any water-soluble ingredients (or those ingredients that typically are added to the water phase even if not strictly water based). You can for example add humectants – posh word for ingredients that attract water – such as glycerine, propanediol, etc floral waters and plant extracts. The oil phase comprises oils, the emulsifier, and wax based thickening agents. 

An absurdly simple recipe therefore would be

80% Water
15% Oils
5% Olivem 1000

And that would work perfectly well. But it’s missing a few components not least of which is a preservative and without which the cream would be good for just 3 or 4 days even if refrigerated. There really ought to be a humectant (glycerine, propanediol etc) – you rarely see a cream without one, so let’s amend the recipe. I’m going to add ingredients that we stock (because I’m shamelessly trying to sell more), but really because I know them and can attest to them.

The heated water phase

Water 75%g
Glycerine or Propanediol 3%
Preservative (Spectrastat OEL) 2%
All of which add to 80%.
Heat the water phase to about 80C – 90C.

At this point we add the water thickener. All emulsions benefit from the inclusion of a water thickener but their inclusion is even more important when working with emulsifiers such as Olivem 1000. A water thickener adds body to a cream but more importantly helps stabilise the emulsion especially at the beginning when we combine the heated water and oil phases. 

There are many water thickeners available – xanthan, cellulose, siligel, sepimax zen, carbomers etc.
We like to use either siligel or sepimax zen in our creams but any will suffice. Many formulators don’t recommend xanthan gum in Olivem based emulsions as the final product can be a bit stringy but it is cheap and reliable and using xanthan at lower levels – say 0.2% should offset any tacky or stringy feel. No such issues with siligel (even though it does have xanthan in it) or sepimax zen both of which add glide to a cream. 

Use siligel at 0.5% to 0.8%, sepimax zen at 0.3%, or cellulose (we stock hydroxyethyl cellulose) at 0.4%
Lots is written about incorporating thickeners into the water phase and to be honest most of the recommended procedures are unnecessarily complicated – combining the thickener with glycerine to form a paste before adding to the water phase, or sprinkling the thickener onto the water and leaving for hours to swell up. Life’s too short for such nonsense. Simply sprinkle the thickener onto the heated water and whizz with a stick blender for a minute or so. Always works for us and we never get lumps!

The heated oil phase

Stand the water phase to one side while you weigh out the oil phase. By time you have heated the oil phase the thickener will have done it’s job and the water phase will be ready to accept the oil phase. 

According to the 80:15:5 rule we ought to have 15% of oils with 5% emulsifier but 15% of plant oils (unless you want a particularly rich cream) is a little high so I’m going to deviate a little from the rule of thumb and reduce the oils down to 12%. But feel free to stick with 15% especially if you are designing a night cream when the richness will be more appropriate

So the oil phase might consist of
12% plant oils *
5% Emulsifier
*(any you like though there are specific properties to each plant oil which ought to be a factor in the choice. Plenty of information about the individual properties of plant oils on the Google machine)

Tweaking the oil phase

At this point I want to highlight a fairly common trend amongst newer formulators. From dozens of e-mails received I’ve come to understand that many formulators believe that to increase the body or thickness of a cream they ought to keep adding more of the emulsifier. This isn’t the right approach: only use as much emulsifier as you need and then use wax thickeners (fatty acids and fatty alcohols) such as cetyl alcohol or stearic acid to increase the thickness of the cream.

A common problem with creams, especially those using plant oils and creams that do not use silicones is micro-foaming commonly known as soaping. Micro-foaming is the tendency of a cream to seemingly absorb quickly into the skin but to then turn white when you continue to rub the cream into the skin and prove a little difficult to actually absorb.

What happens is that the water content in the cream is mostly absorbed quickly, leaving the oils and emulsifier behind – essentially the emulsion splits on the skin. The emulsifier attempts to re-emulsify the oils and emulsifier with whatever water is available. Having more emulsifier in the emulsion than you actually need exacerbates the problem. Unless using silicones such as dimethicone (and silicones are a no-no for natural skincare products) in the cream it is difficult to eliminate micro-foaming altogether, but one can certainly mitigate against it. Using just as much emulsifier as you actually need will help and so in our recipe I’m going to use 3% Olivem 1000 (you can use 3.5% just to be on the safe side but 3% always works for me with 12% oils). The more astute amongst you will have noticed that the ratio of emulsifier to oils is 1:4 – i.e the amount of emulsifier is ¼ the amount of oils. So if you did want to increase the oil content to 15% for a richer cream you would use 4% emulsifier (close enough).

I would then add 1.5 % to 2% cetyl alcohol to the oil phase to create the thickness of the cream. Cetyl alcohol is very useful addition to an emulsion as it not only provides the body but it actually helps mitigate against micro-foaming – don’t ask me why – that kind of in depth chemistry know-how is above my pay grade – I just know that it helps!

Our oil phase looks like this
Plant oils 12%
Olivem 1000 – 3% (or 3.5% for safety)
Cetyl Alcohol – 1.5% – 2%

Combining the water phase and the oil phase

Heat the oil phase to 80C and then pour into the heated water phase while whizzing with your stick blender. A lot is written about pouring the oil phase ever so slowly into the heated water phase as though one was making mayonnaise (an emulsion using vinegar and oil with egg yolk as the emulsifier) so the emulsion doesn’t split – nonsense; I just pour the oil phase in one go and never had an emulsion split because I poured the oil in too quickly. I have had lots of emulsions split but pretty much always because one or more of the supplementary ingredients created an instability. (sidebar – aloe vera powder seems to be one of the most irksome ingredients for causing emulsion instability – Olivem 1000 and Natragem EW really don’t like aloe vera at all!)
Our (almost) complete recipe is now

Water Phase
Water 75%
Glycerine or Propanediol 3%
Preservative (Spectrastat OEL) 2%
Sepimax Zen 0.3%

Oil Phase
Oils 12%
Olivem 1000 – 3%
Cetyl Alcohol 1.5%

If you are happy to leave things there and don’t want to add anything else then we’ll need to adjust the water phase because the total of the above is only 96.5%. if we adjust water to 78.5% then the recipe is complete.

Water Phase
Water 78.5 %
Glycerine or Propanediol 3%
Preservative (Spectrastat OEL) 2%
Sepimax Zen 0.3%

Oil Phase
Oils 9%
Olivem 1000 – 3%
Cetyl Alcohol 1.5%

 

Incorporating esters

I wouldn’t leave the recipe there though. A couple more amendments and then we’ll be done. One of the drawbacks to relying exclusively on plant oils as the base of your oil phase is that the resulting cream can drag on the skin (a good cream ought to glide) and perhaps feel a little heavy and greasy.
To offset this I would strongly recommend incorporating esters into your cream as a simple substitute for some of the plant oils in your oil phase.
I won’t get you bogged down with a chemistry lesson that explains what esters are. All you really need to know is that they are a common group of chemicals that are used in a wide range of applications not least of which is their use in skincare products. Apart from the truly purist products most moisturising creams will contain esters.

Moisturising creams and lotions which rely exclusively on plant oils for the oil phase can tend to feel heavy or greasy, and can drag when applying the cream. Esters counteract any heavy or greasy feeling and improve the slip of the cream. Esters certainly improve the skin feel of a moisturising cream and their use is highly recommended.

There’s an awful lot more to the employment of esters in skincare products and a skilled formulator can incorporate 2, 3, or more esters to achieve a very particular skin feel given that there are so many esters with specific properties that can for example, determine the absorption rate of a cream, the play time of the cream, the ‘slippiness’ of the cream, the skin feel after application and more. But for the formulator who is new to esters let’s keep it simple.

The three most commonly used esters are

C12-15 Alkyl Benzoate

Coco-caprylate Caprate

Capriylic Capric Triglycerides

There isn’t much difference between the three esters as theyare all light to medium weight esters which will reduce greasiness of your plant oils, improve the slip of the cream, and leave a soft, moisturised after feel. subsitute 1/3 of your oil phase with any of the three esters mentioned. For example for a 12% plant oil content, try 8% plant oils with 4% of your preferred ester. You can if you wish substitute half the oil content with esters.

Our recipe has progressed thus

Water Phase
Water 78.5 %
Glycerine or Propanediol 3%
Preservative (Spectrastat OEL) 2%
Sepimax Zen 0.3%

Oil Phase
Oils 9%
Ester (e.g Coco-caprylate caprate) 3%
Olivem 1000 – 3%
Cetyl Alcohol 1.5%