A quick guide to HLB and why you might not need it just yet.
HLB is something that many of you have heard of but few can get their heads around. I can totally understand why as it involves a few of my (not necessarily your) favourite things – Chemistry and Math.
But the thing is you might not even need to worry, well not yet anyway.
HLB = Hydrophilic, Lipophilic balance and it basically describes the ratio between the oil loving and water-loving part of a surface-active ingredient (we often call these emulsifiers as we are usually trying to make a cream or emulsion when we think about HLB).
As you know oil and water don’t mix. This is no big secret and is easy to see for yourself by plonking some butter, olive oil or ghee into a cup of water. You can shake it all you like but once you stop doing that two layers will form. They don’t like each other that way (chemically of course).
So, to make them like each other we need a mediator. The chemical equivalent of the diplomatic peace corp is the non-ionic emulsifier and it is only these types of surface-active ingredient that have a HLB. This is also a source of confusion for some.
These non-ionic emulsifiers come in all shapes and sizes but have one thing in common, a love for both oil and water. However, the amount of love they have for each differs and we give that difference a number – a HLB number.
The numbers range from 1-20 (typically although a quick google search may uncover HLB’s much higher, this isn’t useful 99% of the time).
I have drawn this cute (best I can do sorry) picture to demonstrate visually how a non-ionic two-handed surface-active chemical works. I hope you like it.
In the old days cosmetic chemists would look up the HLB of each of hundreds of possible ingredients and blend a couple together to get the right HLB for their oil base. This worked well when we used oils such as petroleum, lanolin and some basic vegetable oils and waxes and enabled the production of creams, lotions and milks with lots of different textures and properties.
So why do I think that you might not need this beautiful piece of chemistry + math now?
Mainly because the world has changed and instead of slow chemistry like the above, we now have a plethora of ‘quick fixes’ where the HLB calculation has been made redundant. These ingredients are called emulsifying waxes and usually come as a pellet or flake and consist or two or more INCI names – cetearyl alcohol and PEG-20 staerate, Sorbitan olivate and cetearyl olivate or cetearyl alcohol and cetearyl glucoside. With these dudes all you have to do is add it into the oil phase and boom – you are done (well, almost).
I encourage all of my newbies to stop worrying about HLB and get on with using these blended emulsifiers as it enables them to build confidence, see and feel a cream being made. Once they are comfortable with that we can start getting a bit more technical if needs be.
So, there you go. HLB is a cool concept with lots of science behind it but it is not necessary to get bogged down in this when you first start out. Chemistry is a language and science is a culture that many of my clients find weird and confusing enough without diving in with the calculator. However, given time it all becomes clear.
Enjoy your mixing today and if you did want to read a bit more I wrote about HLB in 2010 and fleshed it out a little.