Saturday, October 7, 2017

Weekend Wonderings: How much preservative to use in an emulsified scrub?

In this post, Using black cocoa butter in emulsified scrubs, Vintage Blue asked: If I'm reading this right the preservative goes into the mix before I add the sugar. So I only calculate the preservative based on the weight of the oil mix not the oil and sugar? Wouldn't i be short on preservative if preservative weight is calculated on the final weight of the product? I just want to make sure that my product is well preserved before giving it as gifts to friends.

I'm so happy you want to preserve your scrubs! When I first starting writing this blog, every time I wrote about emulsified scrubs I'd have people not wanting to preserve them, so it makes my heart so happy to see how times have changed!

When I make emulsified scrubs, I tend to use 1% Phenonip, a broad spectrum preservative with a suggested usage rate of 0.25% to 1% in our products. In the end, every 100 gram batch of my sugar scrub base eventually becomes around 240 grams of emulsified scrub as I love to add loads of sugar. This means that I'm using about 0.42% preservative, which is well within the suggested usage rate!

In the formula below, there aren't any serious botanical ingredients that could cause problems down the road, like powdered extracts, aloe vera, or clay, so using 0.42% will work well. If you wanted to add more to the product just to be on the safe side, total up your base plus your sugar or salt, then add 1% of that. So for 240 grams of my favourite scrub, I'd add 2.4 grams total.

10% emulsifying wax (e-wax, Polawax, or BTMS)
10% cetyl alcohol or stearic acid (5% cetyl and 5% stearic is very nice)
20% cocoa butter
56% oil - I'm using soy bean oil here
1% Vitamin E
2% fragrance or essential oil*
1% Phenonip

Check out the post on this topic on how to make it! 

Related posts:
Water activity with sugar or salt scrubs
Debate: What kind of preservative should we be using with scrubs?


Shabnam Askari Ashtiani said...

Thank you so much for your great blog. I certainly have learned a lot from you since discovering your awesome posts. I recently became a cosmetics formulator and can't wait to share my experience with you and your fans 😊
All the best

Blogger said...

At last, you can buy Essential Oils online at discount prices.

Vintage Blue said...

Hi Susan,

Thank you so much for answering this for me. I do have to admit, I was that person that was scared of using preservatives but after reading your blog, I felt more comfortable in using them. I used your recipe one as is and another batch with a few modifications dropped the butters for coconut oil, upped the stearic and used oatmeal in it as an exfoliant and gifted them to friends of mine and they were a hit.

What do you think of using beeswax in a scrub? I was gifted one with beeswax in it and I really like the coated/barrier feeling it left on my skin. If I wanted to add beeswax to a scrub, how much would you suggest using?

Thank you so much.