Butter behaviour is more about triglycerides than fatty acids.
In 2016 I wrote two articles about Shea Butter and felt that I’d totally aced the subject! There was this one on the role of women in the Shea story and this one about its chemistry. While I still look back at these articles and think they are pretty OK, I’m now kicking myself that I let another, bleedingly obvious fact about the chemistry of Shea (and other butters) slide right through my fingers.
The value of viewing butters by their triglycerides rather than fatty acids has only just become apparent to me after I’ve sat here for a few weeks evaluating different butters, oils and waxes under the microscope and comparing that to their usual, eyeballed selves. Even in writing this I’m cringing at how little attention I paid to this, mostly likely because I have a tendency to dive deep and miss the shallow water until I’m done down there and am on the way back up. Anyway, let’s have a look.
We (meaning the royal ‘everyone and their mother ‘we’) tend to talk about oils in terms of their fatty acid chemistry. An oil, butter or wax is said to contain lots of oleic, palmitic or stearic acid and that’s why it feels like this, looks like that or behaves how it does. The only trouble is, for the most part these fatty acids are not floating around behaving in their fatty acid way. They are bonded to glycerin and exist in gangs. We call these gangs triglycerides as I’ve mentioned before no doubt and as you probably already know by your internet reading.
Triglycerides have their own ways of occupying space and time and while they do relate to their component fatty acids in many ways, viewing them only as that misses something interesting.
Let’s explore this first by focusing on three fatty acids that are commonly found in butters as examples: Stearic, Oleic, Palmitic.
As, out of those three, I only have stearic acid as a stand-alone ingredient in my lab at this point in time I can only show you this but I’ll do my best to describe the others with the data I can find. I’ll then share with you some information about triglycerides of these three fatty acids and the experimental data I’m gathering.
Stearic is a C18:0 fatty acid so saturated (no double bonds). On its own it has a melting point of 69.3C
Oleic Acid is a C18:1 fatty acid that has one double bond. It has a melting point of 13-14C
Palmitic Acid is a C16:0 fatty acid (no double bounds) that has a melting point of 62.9C
When I melt Stearic Acid onto a microscope slide and magnify it to 800x I see a jagged, dense crystalline structure which look all sharp and pointy:
Stearic Acid 800x Magnification
Combining 20% Stearic Acid with 80% Caprylic Capric Triglyceride creates a pot-set balm with buttery, snowflake-like texture with a frosted, icy appearance. While it feels quite nice it’s not got enough structural integrity to be useful like this. I chose this as it was the simplest and purest triglyceride I had to hand to use as a model oil phase for these binary systems. It is a C8, C10 saturated triglyceride of known structure. If I was to use a whole vegetable oil as my model oil phase the triglyceride composition would be more variable and there would be other chemicals present (free acids, unsaponifiable fraction including vitamins and maybe plant pigments such as carotenoids). This is what that combination looks like under the microscope:
Stearic Acid thickened Caprylic Capric Triglyceride at 800x magnification
This is what MCT and Stearic Look like in the sample:
My un-tested assumption or hypothesis would be had I swapped Stearic for Palmitic I would have achieved a very similar outcome albeit a little softer and less formed perhapse. This guess takes into consideration the lower melting point of palmitic and my prediction that its shorter chain length (but same orientation) may potentially pack even more tightly than the stearic which is a little bulkier.
As for Oleic with its very low melting point, I’d expect that to remain fluid, potentially even when frozen upon which I’d expect at least some of the oleic to wax-out to the bottom of the sample.
Next we should move onto triglycerides as chemical entities and explore those.
Triglycerides of Stearic, Palmitic and Oleic.
My first step was to hunt down some science papers that already appreciated the glory of the triglyceride and found this paper on cardiovascular disease which, I must say doesn’t sound relevant at first glance.
Berry, Sarah. (2009). Triacylglycerol structure and interesterification of palmitic and stearic acid-rich fats: An overview and implications for cardiovascular disease. Nutrition research reviews. 22. 3-17. 10.1017/S0954422409369267.
What I appreciated about this article was its triglyceride information table which you can see for yourself here: https://www.researchgate.net/figure/Melting-temperatures-of-some-TAG-molecular-species-of-different-polymorphic-forms_tbl1_24427412
This table showed me two things:
- That triglycerides containing the same fatty acids could have very different physical properties and
- That the triglycerides could exist in different crystal shapes and forms.
I feel the need to interject here and state (for my own vanity I presume) that while neither of these things were surprising in and of themselves, my aha moment came from finally seeing this data in front of me and having it clear away my assumptions once and for all. This is why the cooling and setting process for butters matters, this is where the many crystaline forms of chocolate originates from, this is why butters often have a wide rather than narrow melting range, this is why some are prone to grittiness while others are crumbly. This is more important than the individual fatty acid chemistry OR the unsaponifiable fraction data, both of which matter but neither of which matter more than this!
Triglyceride Short-Hand.
Rather than write out the name in full, the nutrition and food industries (which appear to have more data on triglycerides than any others I’ve yet found) use shorthand which I’m finding as amusing as I am helpful.
These are my favourites although I’m willing to accept that I’m probably writing them in the wrong order just so they look funnier and are more memorable to me:
POP = Palmitic-Oleic-Palmitic
POO = Palmitic-Oleic-Oleic
SOS = Stearic-Oleic-Stearic
Many more orientations exist and while Oleic is commonly found in position two, it isn’t always. Physical property wise, the exact position of the fatty acids in relation to each other matters as this determines the shape of the triglyceride and, subsequently, how close (or far away) it can get to other chemicals when present in a formula or even when in the stand-alone raw material. Again, what this means is you don’t know everything about a fat just by knowing its fatty acids, further, that you don’t know everything about a triglyceride just by knowing the names of the fatty acids it contains. Oooohhhh I’m excited now!
Applying this view to cosmetic butters:
I put this table together using information I found across a number of scientific publications outlining the structure, typical composition and melting points of the triglyerides. Referencing more than one paper gave me a higher level of confidence that the information I was finding was typical rather than a one-off. Presenting the data this way was something I decided to do in order to help in me work through how the internal triglyceride structure influences the external appearance and performance of the butters in question.
Looking at this I can see why Shea is such a bugger to work with at times.
I can also get an inkling as to why cocoa butter is smoother than shea and mango and more likely to feel dry over oily.
As for mango, this table seems to provide evidence as to why this tends to be harder and feel less greasy than shea.
The analysis as I see it so far.
Shea is the only butter of the three to have a significant proportion of triglycerides present in a permanent liquid state. It is also the butter with the largest range in triglyceride melting point. Taking it further we can see it has big chunks of triglycerides existing as high, medium and low melting point chemistry at room temperature. If you are thinking that these different triglycerides will bond together and form a new homogenous blend, that’s not the case. Sure they might tangle up together a little but it’s more likely they just swim (swim being the operative word thanks to that liquid) around in their oily pool prefering their own company to that of ‘others’, just waiting for the temperature to change a little so they can melt or solidify some more and cause more chaos.
In terms of crystal chaos I’m not entirely sure how to read this in terms of relating it to what happens in real life but it looks like Shea has the least choices when it comes to crystal structures. It contains 52% of its triglycerides in orientations that can take on three crystaline forms and 27% or nearly 1/3 that exists as just one. Compared to Cocoa which has 3 triglycerides each capable of 3 different crystal structures accounting for 80% of its chemistry it seems quite tame. Mango reads similarly to Shea but we must keep in mind that mango is less likely than Shea to have some liquid fats at room temp so while the potential for crystal morphing is there, the opportunity is more limited given the lack of room to ‘swim’.
NOTE: The greater the potential for movement in a chemical blend, the more opportunity there is for chaos. That’s one of the reasons thickening a product helps to keep its form stable.
Symetry
The potential for symetry to play a role in butter properties is one of the things that becomes clearer once you look at the triglycerides.
POP and SOS are symmetrical, POS is so close to being it can almost be thought of as so.
OOO is, of course symmtrical but it’s also liquid so it can’t play this game.
OOS is, quite frankly a mess.
I’ve still got more to research in this regard but the physics around it intrigue me and others by the looks of it. There have been several papers published that evaluate the crystalline behaviour of fats and lipids, linking them to their triglyceride symetry or otherwise. Here’s one.
The fact that 80% of the triglycerides in cocoa butter are symmetrical or close enough to it is most likely the reason it can be so smooth. That they are comprised of mainly saturated fats is likely the reason they feel dry rather than greasy.
In terms of butters, Cocoa wins the symetry wars, not because it has the most symetrical triglycerides- these three are actually very similar in proportion that way – but because it doesn’t contain the unsymmetrical or low melting point chaos that the other two butters do. So, it can let its symmetry shine un-interrupted.
So can we see this under the microscope?
Above are pictures taken at 800x magnification of pure butters. While it can be hard to work out what we can see here, it’s easy to see the three butters have their own unique structural arrangement.
Mango butter forms little flower-shaped crystals, cocoa is dominated by long curly swirls which I think is beautifully fitting given its African heratige and then there’s shea. Shea also has a curly structure but it’s fibers appear shorter and more C than U shaped. They are also interrupted by crystals every-so-often.
I would be lying if I tried to make out I can tell you exactly what we are seeing yet but feel confident enough to suggest these slides demonstrate perfectly how three simple fatty acids: Stearic, Oleic and Palmitic can come together to form triglycerides with their own unique characters which go on to create butters with their own unique internal structural richness and complexity. One that goes way beyond that of the individual fatty acids.
And with that I’ll leave this article.
This little piece of butter loving is part of my humungous Oleogel project. A project that is keeping me engrossed while I remain mostly working at home thanks to the COVID outbreak. I can’t say I’ve minded that at all and have instead felt transported to so many places both microscopically and real-worldly thanks to the threads of imagination this project has twanged.
I hope you’ve found that both interesting and helpful and that like me, you are sciencing the shit out of this pandemic (reference from The Martian BTW).
Amanda x
What if science is to neurotypicals what life is to autistics…
Scientific thinking comes naturally to me. The way I sit back and observe in order to form a hypothesis to test. The way I listen more than I talk. How I experiment broadly and (often) wildly, off-script even rather than seek to be guided into safe spots with boundaries and expectations. And finally,how I interpret and accept failure, the drive within that keeps me going, lapping up every opportunity, every lesson. Noticing everything, testing everything, accepting everyting. This is the art of paying attention.
Being autistic means I process language and thought differently to neurotypicals (most people).
This doesn’t automatically mean I don’t or can’t undertstand things that people say, it’s more that I have to think about it more. I seem to have come without an ‘assumption’ or ‘instinct’ button in that department, or more accurately that I do have one but mine came without the software (I have to build the software). Anyway, over the years I’ve been teaching science I’ve noticed just how much some basic (in the fundamental rather than judgemental way) concepts struggle to be understood. That no matter how many different ways I try to explain, demonstrate and encourage, these concepts are met with a puzzlement that locks down the bit of the brain that adopts new information.
Anyway, after another two of these moments this week something finally clicked to me. What if science is to neurotypicals what life is to autistics…
Example A: When water isn’t water.
Often I’ll ask a client if their formula contains water. I might phrase this in different ways depending on what other information I’ve been given at that point (water phase, diluted surfactants, extracts that are not oil based) etc. Often the client will say no.
Sometimes the answer is no and they are correct but quite often their formula does contain water, they just didn’t think of their ingredient that way.
Common thinking roadblocks I’ve come across include:
- Thinking that Aloe Juice or Gel is not water.
- Same for Milk, fruit juice, extract-only water phases or honey.
Progressing from there we have:
- That glycerin extracts don’t count as a ‘water phase’ (Ok, this one I can understand to a point but remember, I’m talking to people who call themselves formulators/ crafters of cosmetics or whatever and lets not forget that many people still think glycerin is oil, oily or oil-soluble).
- That many ingredients are blends that include water as supplied (again, definitely something that takes a bit more looking into but again, these are formulators)
Example B: The ingredient can only take one form.
While my customer base is global, there is a concentration of people to whom I interact that are on the same seasonal weather pattern as me. Every time the weather gets cold here I get people calling up worried about their oils going cloudy or gritty, their preservative ‘frosting over’ or their waxes being ‘so hard they can’t get them out of the container’. The most common conclusion to these dilemas I get are that the material has expired, is the wrong material or has somehow ‘gone wrong’. The same thing happens in reverse when the weather warms up.
Sometimes a change in form of an ingredient, especially separation in ingredient pre-mixes, can be a sign the ingredient has expired but in these cases it’s just your regular melting, freezing, evaporating or condensing. The same process most adults accept with water (steam, liquid, snow, ice) but struggle to apply in other settings.
My reflections
As a teacher I welcome these misconceptions as teachable moments. These are moments where you can explore the current conception with the student / brand owner or whatever and walk them through a thought process that (hopefully) opens their eye, granting them an ‘aha’ moment. Often that does happen but it doesn’t always. Sometimes when it doesn’t happen I have to accept that I may not be the teacher for them and that I’ve failed, at other times it may just not be ‘their’ time to discover that – their brain may have the capacity but not the receptivity.
So how is this like being autistic?
When observing these interactions in detatched ‘scientist’ mode while actively participating in them , it seem to me as if the student/ brand owner has tried to make sense of the situation at hand by scanning their brain for an answer among the things they already know. Only the ‘already know’ box doesn’t encompass their whole lives, it only stretches to THIS part of their life. It looks to me like they have a brain cupboard for cosmetic science stuff – a silo or bucket I guess you could call it, a place that is in no way connected to any other information or experience they have.
This situation is also common in teaching, they call it ‘classroom smart, life challenged’ or something like that. An example of which may be the student who can do the math calculations in the classroom with ease because they have their ‘school’ mindset on but put a money sign in frot of the numbers and send them out shopping and they can’t figure out how much change they should get from a 50.
In autism terms this is also quite common. In my personal experience (the only one I’m qualified to share) it has two key underlying causes:
1) my monotropic mindset. This is similar to the silo or bucket mentality above but in this case rather than not being able to de-contexturalise (I can easily do that), I can get stuck on one idea or track and have trouble stepping outside of that zone to gain a broader perspective. In this context I could also call this hyperfocus or flow for me, in the neurotypical type scenario I’m comparing it to, the thought origin may be the same or may well be that no other options are within the frame of reference/ can be imagined. This is often the case when the experience level is low – in that case, it would be a case of jumping to a conclusion.
2) The Overwhelm. Being autistic for me means being easily overwhelmed by the possibilities and input that is all around me. If I’m not in a state of flow, I’m like a boundary-less sponge, soaking up anything and everything, often struggling to work out what is useful and what is not. For many students/ brand owners I talk to in this context, I have to keep in mind that the cosmetic science world is all unfamiliar to them. It’s a world where many act confident on the outside but are actually very vulnerable on the inside. Being overwhelmed for me is made ten times worse when I am in an environment in which I feel alien (which is most places). This is not a state of mind that is condusive to ‘best self’ thinking and again may be driving some of the struggles I observe.
So what next?
As always I’m sharing this with you in the hope it serves to open up thought processes and conversation that may help us all communicate better and be kinder to each other. While it is sometimes frustrating for me as a teacher and mentor to be confronted by these situations it is not (and I repeat NOT) because I think of these questions and/or situations as stupid or pointless. It’s more because I don’t always have the time or buy-in from the people asking to dig deep enough to help resolve this misconception and empower the individual.
I also want to make it clear that I am not implying all neurodiverse people can ‘do’ science and no neurotypical people get it, that’s just the thread of thought that gave me this ‘aha’ moment, affording me a compassion boost and an energy injection to tackle these questions in another way.
Whether my clients are really stuggling in similar ways to my autistic self or whether that’s just my misconception (or projection) I don’t know and don’t know that it matters. What does matter is that we carry on encouraging people to think of their cosmetic science endeavours both more critically (scientifically) and more broadly as that should allow the mind to expand and relax.
And with that I’ll leave you for today.
Break Point – What happens when you squish your balm to death!
As some of you may know I’ve been conducting lots of experiments on Oleogel strength. One of the fun things to do with oleogels is to get them naked then squish them. Here is a video of just that.
These oleogel lumps do vary in size a little but are roughly 2.5cm cubed. I’m re-running these tests with less variable sample sizes and will also make some adjustments to reduce the potential for the pressing to cause a slip and slide action to happen.
In the meantime please enjoy the squishing and I hope you find this filter helpful in highlighting the changes in force type and direction.
When your preservative prefers your packaging to your product
Preservatives are surface-active.
What you are hoping (or aiming) for is them prefering the inter-face (or surface) between your oil and water phases but that isn’t always what happens.
Behold, exhibit A:
A couple of weeks ago a help desk client sent an enquiry about a preservative they wanted to use but that was causing issues in their formula. I could see the current problem was one of solubility as the preservative that had been chosen was just not mixing into the main formula. I confirmed my suspicions with a few lab tests and also tested out a couple of formula adaptations to provide it a more accomodating environment but then kept the original samples to evaluate over time.
On returning to the samples this week I noticed that a couple of the samples had developed etchings on the side of the bottle, the rest of the formula being crystal clear now and with no sediment. Clearly in these samples the preservative was prefering the packaging to the product and had found a way to precipitate out onto the side of the bottle. I do see this behaviour from an ingredient from time to time and it can happen with other ingredient types too such as essential oils, fragrances and colours.
This situation takes a bit of time to develop. In this particular case we could immediately see the preservative was not in solution so the etching effect developed quickly. However, this situation can and does happen more slowly and quietly, showing up as stability issues down the track either in terms of microbial failure (when the offender is a preservative) or a premature loss of colour or fragrance of a product (for dyes or aromatics).
I often hear people talking about solubility as if it is an absolute thing but it is not. Solubility is always relative: this compared to that. It’s also applied – solubility of ingredients in the formula vs in the packaging, solubility under optimal storage conditions vs under stress. These are some of the reasons we take our time when developing new formulations. This is why stability testing is important and why on-shelf vigilance, especially of the first batch of new products comes in (as not all cases of packaging interaction happen during a standard shelf life test or in standard test conditions).
It can be daunting to know of all the ways your formulations can fail, especially when it’s to do with microbial stability. However, it’s also interesting and empowering when you can spot and fix a problem.
The key is to give yourself enough time and develop enough curiosity and knowledge to turn these unfortunate events into opportunities.
Amanda x
Oleogel Testing Experiment Update – The First Round of Data is in!
While it’s fair to say I’m not always the best at reading the room, I would put a good deal of money on me being right that most of you have NOT been joining me in my excitement driven sleepless nights waiting for this data. That said, this project is turning out to be very interesting and likely to provide insights that can spread further and wider than my oleogel under pressure!
So what’s been going on and what am I talking about?
If you didn’t watch the part 1 video go do it now as that will get you on the right page. For those that watched it but can’t remember it (or would rather forget) I am investigating the strength of oleogels both ‘naked’ (unpackaged) and in different types of packaging – plastic, glass, metal and cardboard. I’m doing this for many reasons, not least because many brands are trying to reduce packaging waste by choosing eco-friendly options such as cardboard over plastic. As a formulator, teacher and science communicator I want to explore these consequences in an applied way. So often when you look for science data it’s talking about a single component – say oleogels as a thing or packaging as a thing. By investigating the relationship under stress (some might say all relationships are stressful…) between both the packaging AND the contents I’m producing APPLIED data. Applied data in this case means data that we can APPLY (or use) in our real-life scenarios so when we are trying to work out the pro’s and con’s of choosing this over that container.
Why Oleogels?
Oleogels are weird, that’s why. They have no continuous structure to them which should mean they are floppy, sloppy and leaky but they are generally not, well not all the time. It’s this complexity and weirdness that fascinates me. Their structure changes over time, when you make them different ways and as they respond to stresses and strains. It’s almost like they are emotional little flowers!
In all seriousness oleogel physics are just very interesting. I am leaning towards using Ice (not the drug, no need to panic mum) as a comparrison model as that seems to have similar properties. Oleogels have a crystaline internal structure that can be described as fractal in nature. They also have fluid regions that can leak when the crystals grow big and/or numerous enough. They have regions that generally stay quite fluid thus creating a constant shift in the internal landscape that us cosmetic chemists try to control, often unsuccessfully.
I don’t know about you but I’ve looked back on some of the oleogel formulations I’ve made over the years and found samples that have developed a gem-stone like crystaline structure to them as the balm aged. I’ve also had balms that became so hard over time that you couldn’t use them at all. Balms that split into oily and waxy parts and balms that bounce! When does an emulsion ever give you that much entertainment and confusion?
I also like oleogels because it’s a chemistry that beginners make because it seems simple – just blend wax and oil and you are done! I quite like the way nature has of sticking its fingers up at us and saying ‘you may think I’m simple but I’m going to kick your ass’. Sure, not every oleogel is as tempremental as a teenager with no internet but I’m not interested in those ones, I want these 🙂
Where I’m at with testing.
This round of testing is still in the process development stage so while I’m collecting statistically significant data it’s taking rather a lot of tests to reach that point – ideally I’d be doing 20 rounds of testing per variable rather than 40-60. I will repeat these tests with a slightly modified process to reduce the variability in my data while maintaining its significance (just in case you were wondering). That ‘optimisation’ will then make it possible and practical to run this sort of testing on your products should you want it.
The rest of the information is in this video including some more information about how I’m handling the data I’m producing and how I’m making sure my strength comparrisons are fair and as accurate as possible. There’s a lot of maths involved and I’m just hoping I chose the right equations for this data – I am also going to check that with a physics expert before moving to the next stage.
My hope in sharing this journey with you is that you will start to understand and maybe value the process of ‘doing’ science a bit more. That you may invest more of your own time in running controlled experiments and analysing the data you produce. Finally and importantly given that this is a business, I’m hoping that in sharing this I can demonstrate to you the value of knowing the applied strength of your oleogels and how this data can help you with your own R&D.
Thanks for watching.
Developing a method for press/ squish testing balms and oleogels.
Hello people,
Believe it or not I’ve had a lot of cosmetic sciency things going on in my mind and all over my house (mostly thanks to COVID lockdowns) over the last month or so and I’m just about ready to share them with you. I say ‘just about’ because in my head there’s always more to learn and invetigate and that’s as exciting as it is annoying (because nothing ever feels finished).
Anyway, I decided to share this content with you via the wonders of video because… Why not! In summary what you will find in this 20 minute video is a walk-through of a new testing method I’m developing that YOU (yes you) will be able to access for your balm, pomade, gel and waxy solid style products when the time is right and the crystals are fully charged.
I thought it might be quite nice to share what I’m doing at this, the R&D stage to help you get an appreciation for the science that’s involved in a project like this, the amount of testing that gets done, the time that it all takes and the fact that at the end of it all you have to sit down and do a lot of math homework (oh the joy!)
So come along on this process with me and (hopefully) learn a little more about the science of squishing.
Also note, you can’t submit your products for squish testing (a type of application testing – how your products will perform in-use or in different containers maybe) just yet. I am trying to speed the project up and will introduce this new service on my website as soon as I’ve fully validated my method and worked out how many millions of dollars this service is worth mwahahahahahahaha.
Another note: I didn’t do my hair or make-up for this video because I forgot and it’s likely I end the last frame with an oilier than usual face because I have a habit of touching my face a lot and balms are oily…
Getting INDI brands to class.
Warning, I am going to sound very old and set-in-my-ways in 3, 2, 1…
There is no doubt that social media, especially visual platforms such as Instagram and Tiktok have created the perfect environment for small, start-up brands to thrive. In the cosmetic industry we call these ‘Indie’ brands and we worship them like Gods. Well, I don’t but that’s because the only thing I worship generally is trees and chocolate.
These Indi or ‘independent’ brands birth themselves into the world, growing from strength of their own ideas, sense of entitlement and magnificent aesthetic. Ok, bit harsh but you get the picture.
Some of these Indi brands do eventually realise they need to attend a course or two or seek some professional help (collaboration darling, they seek collaborations – a meeting of minds) but only after their usual research tricks – searching You Tube, the blogs and social content of other Indie branders for free tips and recipes or asking their followers for feedback on each brain fart they have – draws a blank.
Their reluctance to go outside of their Indie bubble doesn’t stem from fear of them finding out they actually don’t really know enough to own a brand by themselves as that thought would never cross their minds. No, this reluctance is based on a lack of tolerance for anything deemed borning and non-goal orientated. They want to launch product X so they want to lean HOW to make product X because only they have what it takes to make things for their brand.
As a teacher (sorry, ‘collaborator’) Indi brands will tell me without telling me they don’t want to waste time exploring the science and reality that product X will be built on, they also aren’t that interested in learning how to formulate X from scratch although it will shit them when it turns out you can’t easily match a multi-national brands top selling anti-ageing cream when only using whole food type ingredients sourced from your garden. Who’d have known…
Yes these Indi brands have high standards, lots of ideas and zero tolerance for my shit and there’s nothing wrong with that is there ladies and gents?
Thinking a little skin science may be a good place to start I bring that up but that falls flat on its beautiful face also. The Indie brand has already got skin science nailed and not just because they have been hash-tag ‘genetically blessed’ and are still under 30. They learned everything they need to know about problem skin (which they don’t have) from Dr Pimple Popper and gleened from (you guessed it) You Tube and that Netflix series ‘Skin Decision’ (which is actually very good). My cosmetic science take on the dermis and how to facilitate better dermal penetration just can’t compete.
But they finally come to school, mostly to teach me how good they are, create some memories for their Insta feed and take selfies in a lab coat (there will be lab coats right?).
I’m mostly joking of course and while some of these things are definitely true some of the time, on the whole, Indie brand owners are as interested in cosmetic science and learning as the rest of us and a little background meandering never did anyone any harm.
Happy formulating.
Amanda
Natural Preservatives Vs Letting Nature Do its Thing.
Three months ago I prepared a large batch of this natural cream. I split the cream into several portions and to each portion added one of nine different natural, nature identical or naturally derived preservatives/ preserative blends. The tenth sample is the one on the right which I left with an incomplete preservative strategy while sample zero, the unpreserved base is shown as the one on the left. After adding the preservatives I re-adjusted the formula pH to a suitable level so I could compare the samples against each other fairly.
All of the other samples in this trial worked well and preserved the cream adequately based on the measures I undertook. A full report of that is being uploaded to the New Directions Website to act as a teaching aid. However, it was these samples which intrigued me most. The way they nourished different microbes because of that one change – that being potassium sorbate 0.5% on the right and nothing on the left in a formula base set at pH 5.5.
It’s not a great idea to grow your own microbiological weapons under your desk so I didn’t keep these for longer than I had to. I kind of regret not sending them off for analysis but am also not sure I want to know what grossness was existing in these cream samples. What I am happy about is that these two failures made my good guys look oh so much better and made me feel proud that the other options I’d chosen had (as far as I could tell) been able to defend its self against this horror show.
I often get people tell me how they don’t need to preserve their product as they keep it in the fridge or only make as much as they need and then make another fresh batch. This makes me cringe on the inside…
I ponder how I must have by now earned the right to call myself the champion growner of mouldy cosmetics due to the fact I do so much experimenting (not because I’m crap of course although some days, I actually can be) and maybe that’s a good thing. I’ve got plenty of lived experience of just how fast your beautiful creams can turn into a shit show of epic proportions when you don’t know what you are doing. That said, I’ve also got plenty of evidence to show that following a few simple steps and being somewhat sensible is all you need to ensure this doesn’t happen to you – there’s really no need for a full body suit and end-of-lease cleaning squad each time you get the cosmetic chemicals out just don’t lick anything or pick your nose while on the job.
Questions around product preservation still top my in box each week with many people taking extreme positions aroud what they will and won’t use and can and can’t try. While I respect that paper research on one level, I know that it’s only when the theory hits the practice that we start to see what your ideas are made of. I just wish people would experiment more. It is for that reason that I put together this little experiment, to encourage people to experiment more and to take my starter-for-ten and run with it. So what if you end up with a few failures, the below samples are not nothing, they are beautiful lessons in their own right. They show us the microbes that were hiding in the formula all along, of what Potassium Sorbate had to kill before it met its match in black hairy land. This is the stuff epic lab tales are made of.
And with that I’ll go back to my work as I’ve got more samples to process and more reports to write up. Oh and if a microbiologist does see this post and comment ‘oh wow, your hands must have been covered in poop when you made those’ I really don’t want to know. Thank you and goodbye 🙂
Castor oil is not like other oils.
As exciting as it is to browse through the hundreds of different vegetable oils that are available to today’s cosmetic chemists, most of them, for the most part, are chemically quite similar. What I’m referring to here is the fact that the majority of vegetable oils are comprised of triglycerides dominant in Oleic, Linoleic and Linolenic fatty acids. While there is absolutely nothing wrong with that, there are occasions when it’s nice to work with something different, something that behaves a little more interestingly, that stands out from all the rest in some way. That’s where Castor oil steps in.
If you’ve ever wondered why castor oil performs better than your typical veggie oil at solubilising pigments, why it is often used in skin cleansing formulations or why it’s popular in hair and eyelash treatments, it is due to its unique and interesting chemistry.
Castor oil conforms to the usual oil structure of being dominant in triglycerides but its fatty acid of choice is Ricinoleic rather than oleic, linoleic or linolenic acid.
Ricinoleic is a C18 fatty acid and just like Oleic it also contains a single double bond. However, Ricinoleic also contains something else – an extra hydroxyl group on its fatty tail – another -OH or, in chemistry speak Oh My God That Changes Everything!!!
This extra -OH group on a C18 fatty acid that typically makes up between 85-90% of the oil makes Castor a whole lot more polar and surface-active than your average oily triglyceride. That explains why Castor oil is much more interested in getting up close and personal with other polar chemicals in a similar way to that of a surfactant/ emulsifier. While it would be misleading to hint that this oil can be used as an emulsifier – it’s not polar enough for that – the extra -OH’s does give Castor oil an ability to modify the surface tension of a formula in a way that non polar oils simply cannot and that feature can be very, very useful!
Surface tension is a repellant force that exists at the interface between an oil and water phase. This may be within a product (say, at the oil:water boundary of an emulsion) or during product use (when you try and spread a product through the hair or across the skin). The bigger the difference in polarity between the phases, the greater the interfacial force and potentially the greater the resistance to flow (less spreadable product).
While some surface tension between phases is desirable and required to maintain the integrity of an emulsion or multi-phase product, it’s often possible and preferable to create formulations that are a little less highly strung and more relaxed. Adding more polar ingredients to an oil phase of an emulsion or at the emulsion interface (eg caprylyl glycol) can improve spreadability. In formulations that contain a water phase, another surface-tension modification option is to decrease the polarity of the water phase and this can be achieved by adding glycerin, glycols or alcohol. Often multiple strategies are used to balance out the benefits of a reduced surface tension with the requirements for creating a stable product. So it could quite easily be the case that polar oils are used to increase the polarity of the oil phase while glycols are used to reduce the polarity of the water phase.
This surface-tension modification can be used by formulators to increase the spreadability and flow of a formula, and so the fact Castor oil can help with this more so than most other oils is what makes it such an interesting and useful ingredient.
Castor oil is quite safe to use and has a low potential for triggering allergies but it can turn rancid quite quickly thanks to this very feature that makes the oil so interesting – the joys of double bonds and oxygen groups! As such, it’s definitely best to avoid storing this in warm environments, in UV exposed locations or where moisture can get into it – I’d definitely recommend limiting the oils head space but would not advocate storing this in the fridge, a room temperature cupboard should suffice.
In terms of identifying when castor oil is going off that’s not too difficult actually. This oil becomes much darker in colour when it oxidises going from a light yellow to a darker yellow and onto a slight orange tone. Ironically the oils propensity for this is what got it kicked out of most lipstick formulations back in the day as people got fed up with their lipsticks getting progressively more orange after a few months of being used.
In spite of its succeptibility to oxidation, this is a good oil. It’s cheap, widely available and has some really interesting chemistry that delivers a multitude of benefits in a formula.
I love it when a simple, low-key ingredient that many people take for granted is uncovered as a having chemistry super-powers like these. It stories like this that make my chemistry world go around!
Enjoy.
Amanda x
PS: for those who are interested, here is a link to one of the articles I reviewed when checking up on the composition of Castor Seed Oil.
Mutlu, H., & Meier, M. (2010). Castor oil as a renewable resource for the chemical industry. European Journal of Lipid Science and Technology, 112(1), 10-30.
The Curious Chemistry of Glyceryl Stearate
Click here to listen to an audio version of this article via our Podcast
Until last week this commonly-used cosmetic chemical had been something I’d never, ever thought of looking into. I hadn’t questioned its chemistry or function having used it many times in many different formulations and while I knew of and appreciated the difference between the SE and non-SE versions of this (SE = Self Emulsifying indicating the presence of a little saponified fatty acid to help turn up its emulsification properties) beyond that, I had next to no interest in spending time analysing this. That has since changed.
It came to my attention recently that this particular chemical can be sold under another name – mono and diglycerides or monoglyceride or variations on that theme…
Chemically speaking glyceryl stearate is (or should be) a monoglyceride.
As someone who takes most things literally (why wouldn’t you), I read this chemical as being one-part glycerine and one-part stearic acid. In my book that also makes this a monoglyceride but why call it a monoglyceride when that’s less specific and useful?
The name glyceryl stearate is telling us exactly what this chemical is or so I thought…
Glycerides.
Glycerides are esters formed by combining glycerine with one or more fatty acid.
At this point it is useful to remember that glycerine likes water and fatty acids typically like oil. Putting those two things together on the one molecule generally gives us a surface-active ingredient. In this case it’s accurate to think of glycerides as having some degree of emulsification power.
Three different families of glyceride exist:
Monoglycerides are where there is one glycerine attached to one fatty acid. This arrangement leaves two of glycerines functional groups (or bonding hands) free to make new friends and influence people. The fact that two water-loving functional groups are left available makes monoglycerides most surface-active and most useful to the cosmetic chemist looking for emulsification properties.
Diglycerides are where there is one glycerine and two fatty acids. This leaves one glycerine hand free for bonding thus reducing the emulsification power of this type of chemical but still leaving a little opportunity for useful surface-activity.
Triglycerides are one glycerine and three fatty acids and at this point we have what can only be described as an oil. There’s no water-loving at all going on at this point.
Triglycerides dominate the chemistry of most vegetable oils and are typically used as reference points for identifying an oil and analysing its quality, features and benefits. As veggie oils can contain up to 90 or more percent triglyceride it’s not uncommon for other minor oil chemistry that exists to be entirely ignored but in reality, most vegetable oils contain some di and mono glycerides plus an unspecifiable fraction within their natural chemistry and all of this is useful.
Broad vs Narrow Vs specific cuts.
My first ‘aha’ moment came when I realised that in the world of glycerides, it is quite often incorrect to assume you are buying a material with an exact and precise chemistry.
There are a few different reaction paths ingredient manufacturers can take to create an abundance of monoglyceride (of which some might be glyceryl stearate AKA glyceryl monostearate). Both the choice of feedstock oil and the reaction pathway the manufacturer chooses influence what you end up with, sounds obvious enough now it’s been mentioned.
Choosing your feedstock.
As glycerides exist abundantly in vegetable oils and as vegetable oils are readily available to the cosmetic ingredient manufacturer, it’s highly unusual these days for this chemistry to come from anything other than vegetable sources with the most likely being palm. This wasn’t always the case and when I first started in the industry, we regularly had to ask if the fatty acids and glycerides were tallow (beef) derived but BSE and other global regulatory changes put an abrupt stop to that. Mineral oil does not naturally contain glycerides and as such, is less likely to be the feedstock for this type of chemistry.
Generally speaking, most commonly used feedstock oils are dominated by C18 fatty acids with a typical oil having between 70-90% of its fatty acids in this configuration. C18 fatty acids are most commonly found as Oleic (C18:1) and Linoleic (C18:2) with the remainder as Stearic (C18:0), Linolenic (C18:3) and Alpha Eleostearic (C18:3). This may be why the fatty acid in glycerides is often referred to as stearate, a sort of catch-all that tells most but not necessarily all of the story. More on that later.
Doing the chemistry.
Once a feedstock oil has been selected the next step is to chemistrify it!
There are many reactions you can do to end up with Glyceryl Stearate, but two of the oldest tried and tested methods are a) glycerolysis or b) direct esterification
Glycerolysis.
The simplest way to generate some monoglycerides involves heating your feedstock oil (triglycerides) with glycerine in the presence of a little catalyst (which could be sodium hydroxide). The catalyst isn’t enough to completely saponify the oil so the triglycerides don’t break up completely but the combination of heat (180-250C), slight alkalinity and extra glycerine produces just enough of an enticement for some of the triglyceride fatty acids to swap their triglyceride relationship for a new mono or diglyceride bond.
This paper contains a lovely graph to represent this change over time, showing that an almost 100% triglyceride starting material at time 0 transforms to a 26:18: 66 mix of mono:di:triglyceride after 1 hour and progresses to 40:30:30. Mono:di:triglyceride at the 3 hour mark beyond which the diglycerides increase with a corresponding drop in triglycerides to end up with a 40:48: 12 mono:di and triglyceride blend after 6 hours.
Seeing this data helps to explain what I’ve been seeing as I’ve been investigating this chemistry and what’s on offer from different manufacturers. It’s quite common for an ingredient manufacturer to be offering a range of monoglycerides for sale with varying percentages of mono and diglycerides. In some cases, some of these materials are called glyceryl stearate yet come with specifications that indicate they too are blends of different glyceride chemistry. It’s potentially very confusing!
Direct Esterification.
Another method for creating monoglycerides is to react a fatty acid with glycerine thus creating a monoglyceride.
This reaction is what I thought was happening all along but as it’s more complex and takes a few more steps, it’s actually not the most common method.
Gaining access to fatty acids requires saponification of the oil (triglyceride) to fully break the glycerine: fatty acid bond. This is a common reaction within the cosmetics industry and is often the first of many chemistry steps oily feedstock goes through in order to create the exact chemistry we require for our creams, serums and soaps.
During full saponification, the glycerine is siphoned off into another vessel. Then the fatty acids which are now free from their glycerine bonds can be fractionally distilled or sorted. This sieving of the fatty acids utilises the different melting points of the different chain length and bonded fatty acids to separate them. While I like the idea of ending up with completely sorted and isolated fatty acids, again the reality is not quite that simple. Different markets require different things and it’s much cheaper to broadly separate the fatty acids vs doing it to a more precise level and indeed, that’s exactly what happens.
Unless specified (and paid for) Stearate fatty acid cuts typically include some C16 and all the different C18 arrangements, not just the C18:0. This isn’t necessarily such a big deal and I feel in danger of becoming a little pedantic here but it is worth noting. In a manufacturing environment, whenever a variety of chemistry (or broad cut blend) can be sold under one chemical name, there’s a greater potential for the ingredient to perform differently when moving from one manufacturer or supply source to the next. This is a lot less of an issue when the chemistry is precise. Further, this is likely to present as a bigger problem if these changes mean the resulting chemical isn’t as strong an emulsifier as the previous version. I can see that being a possibility here.
Before we leave direct esterification behind I’d like to come back to the stearate name again and add a little detail to our understanding. As I mentioned again above, C18 chemistry in oils typically goes beyond just stearic, the saturated fat and includes mono and polyunsaturated fatty acids. These double bonds are unwelcome complications when we are trying to further react these fatty acids so often, after saponification and sorting into a ‘stearate’ cut, the stearate chemistry is hydrogenated to leave a C16-C18 fatty acid blend that no longer contains any double bonds. This chemistry is typically sold as hydrogenated palm stearine as we see here and is a very common raw material used by many cosmetic ingredient factories.
While direct esterification sounds so simple and elegant, it’s actually a multi-step process and one that can still result in a few variations on the monoglyceride theme.
Why do we use Glyceryl Stearate?
Cosmetic formulators and manufacturers will often reach for the glyceryl stearate as a co-emulsifier for their oil-in-water emulsions or as a surface-tension modifier for their oily balms. The self-emulsifying version of this chemical is more popular in our industry due to it having a higher HLB (more water-loving so better emulsification properties) but as the step that turns one into the other occurs as a final step in the process, it’s not usually that which causes the issues I’ll talk about next.
Both glyceryl stearate and the SE version have the potential to be based on broad or narrow cut fatty acids and be formed via the glycerolysis or direct esterification reaction pathway and this is significant. The reality is that you can be buying glyceryl stearate and end up with an ingredient that is exactly that: glycerine plus stearic acid you could be buying a blend of mono and diglycerides in a range of proportions with only 30-60% of the mix being monoglycerides and only some of that being glyceryl stearate.
Does this really matter?
For some applications this will not be an issue. All cosmetic ingredient suppliers know the HLB, melting point, acid value and rough chemical breakdown of the ingredient they are selling you. Generally, if you are using this as an emulsifier and the HLB is as expected, things will work out.
Where problems can and do occur is where the nuance and variety that exists within this chemistry is not understood or fully appreciated and brand owners, formulators or manufacturers change supply source frequently without fully testing new material in situ (in a representative formula). It is much more likely for cosmetic manufacturers to run into issues when the glyceryl stearate they source is predominantly marketed to the food industry as they favour glycolysis as a means of producing monoglycerides (of which glyceryl stearate is one). They do this as glycolysis is cheaper and faster plus it produces chemistry that works well for the food environment. Manufacturers and formulators are much more likely to get a higher percentage of glyceryl stearate in a narrow-cut fatty acid blend when shopping from cosmetic ingredient manufacturers. This isn’t to say we can’t shop around and use both, more that we need to understand the potential problems in doing this and not just focus on convenience, natural declarations, material origin (palm alternatives) or price point (glycolysis is a cheaper reaction pathway).
Glycery Stearate- the final word.
Don’t take it as a given that you are getting what you ask for. It’s not the supplier’s fault, it’s not illegal or immoral to sell this chemical as monodiglycerides, monoglyceride, glyceryl stearate or glyceryl monostearate. These terms are all accurate but they don’t give the average cosmetic manufacturer enough information to go on. Do yourself a favour and check out the spec carefully then test out the ingredient to make sure it performs the job you are buying it for and if it doesn’t (or doesn’t seem to) now you have a bit more insight into why.
Isn’t chemistry great!
Realize Beauty 