Monday, September 11, 2017

Weekday Wonderings: Is emulsifying wax part of the oil phase?

In this post, How can you tell it's a good recipe?, Connie asked, I am confused, however, about the percent of emulsifier relates to total percent. I understand that amount of emulsifying wax is 25% of % of oils. But isn't the emulsifying wax considered part of oil phase? When I add that in, isn't it going to change all my percents? I may be overthinking this. :/ 

Emulsifying wax is incorporated in the heated part of the oil phase, but it's not part of the "oil phase" or the oil soluble ingredients that need to be emulsified into the product. We need to know the total of the oil soluble ingredients in a lotion to figure out how much emulsifier we need to use.

Calculate everything that has to be emulsified in your formula. This includes things that might be in the cool down phase.

10% cocoa butter
10% rice bran oil
3% cetyl alcohol
1% beeswax
2% tetrahexyldecyl ascorbate (oil soluble Vitamin C)
1% tocopherol acetate (Vitamin E, oil soluble)
1% fragrance oil

We have a total of 28% oils in the formula. If we are using Polawax as the emulsifier, we'd want to use 25% of the total amount in emulsifier. So 28/4 = 7%. So we're using 7% Polawax in this formula.

HEATED OIL PHASE
10% cocoa butter
10% rice bran oil
7% Polawax
3% cetyl alcohol
1% beeswax

COOL DOWN PHASE
2% tetrahexyldecyl ascorbate
1% tocopherol acetate
1% fragrance oil

Please note, only Polawax has the 25% rule of thumb. Emulsifying wax is 25% plus 1% - so in this formula we'd be using 8% non-Polawax emulsifying wax. And other emulsifiers have other rules, so you have to figure out what you have and what that one requires.

The rest of the formula would be the distilled water and preservative, so something like 0.5% liquid Germall Plus, and 65.5% distilled water for a total of 100%. We don't figure out the water amount until the rest of the ingredients are in place. The water amount is whatever is left over.

You may see formulas that note "water q.s" and this means "water to 100%". I tried that for a while, but people got annoyed with me, so I figure it out now.

Related posts:
Polawax versus other emulsifying waxes

3 comments:

Kirsten Thomas. said...

Susan, this makes is more clear than any example I have seen. For beginners it might be good for you to clarify why cetyl alcohol is part of the "oils". I know when I was starting, that was very confusing as it does not appear to be an oil. I thought I'd just mention that some of your posts lately have been super duper...I am especially loving all the new products you are testing. Hope the weather is better now, and the lab is comfy!

Debbie said...

Susan, I am pretty new to lotion making and your website has helped me immensely. I love getting the science as it really helps me understand. The comment above by Kirsten was the first question that came to my mind. I read your post about cetyl alcohol and didn't see anything about which phase to put it in. I've seen others describe cetyl alcohol as a co-emulsifier but this terminology tends to confuse me when I try to figure out what goes where. Would it be better to think of it just as an emollient/thickener? I'm slowly getting a handle on the phases and percentages. Thanks for your help.

Susan Barclay-Nichols said...

Great suggestions! You'll see a post about this on Friday, October 6th, 2017. Thanks for sharing your thoughts. It helps me get a handle on what people are thinking! Thanks, Debbie and Kirsten! :-)