Sunday, July 30, 2017

Lush's main emulsifier: Stearic acid and triethanolamine

One of the companies I'm asked most about is Lush, and their products are the most requested duplications on my Patreon subscription page. (This month I duplicated the Tea Tree Water Toner, the Jumping Juniper shampoo bar, the Godiva shampoo bar, and the Ocean Salt, which appears tomorrow.) I know the most visited duplication on this blog is for the Lush Dream Cream, so let's take a little look at their main emulsifier - a soap made from stearic acid and triethanolamine.

When we take stearic acid - a fatty acid we can buy as a flake - and triethanolamine - an alkaline pH adjuster - and combine them together at a 2:1 to ratio, we create a soap called TEA-stearate, an alkaline salt of stearic acid through the process of saponification. (Reference*)

When we create soaps from oils and lye through saponification, we're using a very alkaline thing - the sodium hydroxide - to turn the fatty acids into things like sodium tallowate (from tallow), sodium oleate (from oleic acid), or sodium palmitate (from palmitic acid), and so on.

These soaps are surfactants or surface active agents, meaning they get into the interface between oil and water and bring them together thanks to the hydrophilic or water loving head and the lipophilic or oil loving tail.

Related posts: A slightly more in depth look at emulsification

I'll be writing more about soaps and soap making in August as I'm trying these soaps I made back in May and July! If you'd like to see the lecture by Kevin Dunn that changed the way I see soapmaking, click here for the notes! Here's a super chemistry based way to explain it from the University of Calgary

To summarize: We saponify stearic acid by using triethanolamine to create an alkaline soap that can act as an emulsifier.

When using this combination, you'll want to use more stearic acid than you need as you want to ensure all the TEA is reacted. You'll see in the formula below, I'd have something like 3.9% TEA to 8% stearic acid to create a thick product. I'm increasing the stearic acid to 10% as I want it to thicken as well. If you'd like to use less, try 1.9% TEA and 4% stearic for a thinner product.

Here's the problem with this emulsifier: Because it's a soap, it has an alkaline pH over 8. Our skin has an acidic pH of around 4.7 to 5.5, and ideally a leave on product like a lotion would have a similar pH. Soap, by definition, is alkaline. If the pH drops into the neutral or acidic realm, it'll fall apart.

As well, it has a huge issue with the soaping effect, which is the white streaks you can get on your skin when you're using a lotion. Adding some dimethicone to the mix can help with that, but it's pretty much inevitable when you're making something with this emulsifier. There's nothing wrong with the soaping effect, but some people don't like it.

In light of all of this, here's what that Dream Cream formula might look like with this emulsifier instead of the 7.5% Polawax I previously suggested. I thought I'd try it again to get to a more authentic duplication.

I've reduced the chamomile and rose hydrosols down to 15% each as these are acidic ingredients and we need to keep an alkaline pH for this emulsifier to stay together. I'm adding back distilled water to make up the rest of the water phase. I've taken out the powdered chamomile extract as we have chamomile essential oil and chamomile hydrosol in the mix. If you don't want to use that essential oil - it can get quite spendy at times, and has an earthy odour that some of us, including me, don't like - use instead 0.5% powdered chamomile extract. Just note that the extract might contribute a bit of a beige-y colour to the finished product.

I don't have benzoin, so I'll use 0.05% Vitamin E, T-50, blend to retard rancidity of my oils. Having said that, the stearic acid has a two year plus shelf life, olive oil a year, cocoa butter at least two years, and cetearyl alcohol at least two years, so you really don't need an anti-oxidant in this product.

One version of this I made had a pH of 8.01.

22.1% distilled water
15% chamomile hydrosol
15% rose hydrosol
3.8% triethanolamine
3% glycerin
2% hydrolyzed oat protein

16% olive oil
10% stearic acid
10% cocoa butter
1% cetearyl alcohol

1% Germaben II (If you want to use Phenonip, please use 1% - 0.5% in the heated water phase, 0.5% in the cool down phase)
1% essential oil blend - rose, chamomile, tea tree, lavender - I'm not sure about the proportions of each as I haven't smelled this product.
0.1% Vitamin E, T-50 anti-oxidant blend

Please use the basic lotion making instructions for this product. Please note that I'm using Germaben II or Phenonip as the original product uses parabens as a preservative. Feel free to try another preservative - I'd suggest Liquid Germall Plus at 0.5% - or consult the preservatives section of the blog for more information.

If you want this to be a bit thicker, you can add more cocoa butter - although that may be way too greasy for your tastes - or up the cetearyl alcohol to 3%. If you really hate the soaping effect, then try adding up to 5% dimethicone in the cool down phase and remove 5% from the olive oil amount to compensate.

Let me know what you think of this new version in the comments below!


ME G said...

Hi Susan, my apologies for bothering you. But PLEEEASE! Could you be so kind to put me out of my misery!?? I am begging you!!!
How do you regulate/adjust the PH in anhydrous products, i.e in conditioner bars! Both Varisoft and Tegoamid s 18 in order to become cationic need low PH, otherwise they are just an emulsifiers. Am i right? If that the case, how do you lower the PH in solid conditioners? OK, one can add lactic/citric acid soln. to the mix, but my puzzle is PH does not relate to anhydrous products...?
So, does this mean that Varisoft is not for solid conditioners?
Many thanks beforehand for your time.
i am sooo confused with this, please help me to understand, i was looking for answers to this for a year now...
Kind regards, Irina.

Susan Barclay-Nichols said...

I'm working on this one! I need a bit more time as it's too hot to get into the workshop!

Michelle Kot said...

OK, thank you, will wait!