Wednesday, August 21, 2013

Wednesday Wonderings: What is the usage rate for an all in one emulsifier?

In this post, You don't need to use the HLB system with an all in one emulsifier, Anonymous asks: I love your blog and have been reading it for almost a year now. Can you just confirm that the usage rate of an all in one emulsifier is the percentage of the oil phase only? Because up until now I have been using BTMS which is 6% (I think) of the whole amount of product I make.

Great question, but please note that I do not allow anonymous posts on the blog. A simple, "Bye, (insert name here)" is enough to keep the comments from being deleted. I will keep this one around, but there are dozens I've deleted, regardless of content. Please remember to do this as it makes the blog a much nicer place!

We figure out how much emulsifier to use by looking at the oil phase, but we add it as part of the entire recipe. 

The way to figure out how to use your emulsifier is to take a look at the suggested usage rates from the manufacturer. In the case of Polawax, we use 25% of the oil phase in emulsifier. So if we have an oil phase that looks like this...

10% jojoba oil
10% fractionated coconut oil
5% cocoa butter
3% cetyl alcohol

Our oil phase makes up 28%. Let's convert this to grams to make it a little easier. So if we have 28 grams of oil, we would multiply 28 x 0.25 and get 7 grams. So we'd ues 7 grams of Polawax in 100 grams of product.

TOTAL OIL PHASE
10% jojoba oil
10% fractionated coconut oil
5% cocoa butter
3% cetyl alcohol
7% Polawax

So Polawax would make up 7% of the total amount of the product. We use the total amount of the oil phase as the basis for the 7% figure.

The 25% rule ONLY applies to Polawax, not to any other emulsifier. (For e-wax NF, many suppliers suggest figuring out the 25% oil phase amount then adding 1% more to that.) Each one has a suggested usage rate, and you should follow that. However, the suggested usage rate is for the whole recipe. If you are using 8% Ritamulse SCG, you would use 8% in the recipe...

10% jojoba oil
10% fractionated cocont oil
8% Ritamulse SCG

In the case of BTMS-50, if you wanted to use 6% emulsifier in this made up oil phase, it would look like this...

10% jojoba oil
10% fractionated coconut oil
5% cocoa butter
3% cetyl alcohol
6% BTMS-50

The BTMS-50 makes up 6% of the entire recipe, not just 6% of the oil phase (6% of 28% oil phase would be 1.68%).

Related posts:
Calculating percentages in lotions
How to convert recipes from percentages to weight
Learning to formulate: A note about percentages

4 comments:

Michael Murphy said...

I make a lotion that is leaving white smear marks on my face. It's not a tragedy, but I don't like it. I've increased the % of water, no change (now (75% water + 18% carrier oils + 6% E-wax NF).. I'm wondering if it's the amount of emulsifier? I tried reducing E-wax to 5%, but no change. Stumped.

Susan Barclay-Nichols said...

Hi Michael. It's called the soaping effect, and I go into greater detail in today's Monday Wonderings. Please provide your full recipe and process if you want further help. It makes my life so much easier, and it means that I'm more eager to respond to a problem when I don't have to do a ton of writing back and forth!

Ronnie A said...

Hi is PEG-20 (Polysorbate 20) the best emulsifier to use for a oil and water hair mist.

What percentage of Polysorbate 20 would i need to use if my formulation is approximately 20-25% oil and 70% water/Rosemary Floral Water and aloe vera juice

Susan Barclay-Nichols said...

Hi Ronnie. I've answered your question in today's Weekend Wonderings. PEG-20 and polysorbate 20 aren't the same thing, so I've answered your question as if you were asking about polysorbate 20. The short answer - you're making a lotion. If you want to use polysorbate 20, you'll have to use the HLB system and choose a low HLB emulsifier. Or just use another positively charged emulsifier because you're effectively making a lotion and polysorbate 20 can't handle it. I can't answer it all here - check out the post!