Tuesday, September 17, 2013

Ingredient: PEG-40 hydrogenated castor oil - my methods for testing

I finally found time to play with my PEG-40 hydrogenated castor oil over my holidays, so let's take a look at the results of my experiments! (I've done this kind of testing before using caprylyl/capryl glucoside. Check out the post here!)


I chose four different fragrances that I hoped would cover the kinds I might choose in the future. From left to right - Black Amber Lavender, Yuzu, peppermint essential oil, and Clementine Cupcake.  I figured these would represent lavender, citrus, peppermint, and vanilla, which seem to be my core fragrance choices. I recognize your mileage may vary with your favourites.

It seemed like everything I was seeing about this solubilizer indicated that I should use something like 2% PEG-40 hydrogenated castor oil to 0.8% fragrance oil, so I used that as my starting point. I added 4 grams of PEG-40 to 1.6 grams fragrance oil and mixed them in a cute little shot glass for each fragrance oil. I mixed 400 grams of distilled water with 2 grams (0.5%) liquid Germall Plus to create a water/preservative mix.


I wanted to test different concentrations, so I chose to use...
  • 24 grams distilled water with 0.5 grams PEG-40/fragrance oil mix = 2.04% (0.2 g FO/EO, or 0.82% FO/EO total in the product); 
  • 24 grams distilled water with 1 gram PEG-40/fragrance oil mix = 4.00% (0.4 g FO/EO or 1.6% FO/EO total in the product); and 
  • 24 grams distilled water with 1.5 grams PEG-40/fragrance oil mix = 5.88% (0.6 g FO/EO or 2.35% FO/EO total in the product).
I put the fragrance oil mixture into the test tube, mixed it well by shaking and using a plastic stir stick, then added 10 grams of water and mixed well again by shaking and the plastic stir stick before topping it up with 14 grams of water to make 24 grams. I gave it one last shake after mixing. (You can see they are a little foamy because I shook them and that's what happens with surfactants!)

I  let them sit for six days. I took pictures on the day of the experiment with follow up pictures on day 6 and day 11. I have not shaken or mixed these test tubes since the initial mixing, so what you see is what they look like when they are allowed to sit. They were placed in the window of my workshop with indirect sunlight every day. My workshop is a little warmer than the rest of the house, often the same or close to the temperature of the outside, and we've been over 20˚C each day, so it was warmer than room temperature.

You can see from the picture I did something wrong with the tube of 4% black amber lavender: I shook it without completely getting my thumb over the end of the tube, so I lost some water. I don't use that in the tests because I have no idea of the concentration, so I've ignored it in analyzing what I've learned. I do use all three in pictures because it looks more balanced to have three things than two. 

To summarize:
  • I chose four fragrances that I thought might represent the fragrances I use the most - Black Amber Lavender, Yuzu, peppermint essential oil, and Clementine Cupcake.
  • I created a standardized mix of my selected fragrance using a ratio, by weight, of 2.0 grams to 0.4 grams PEG-40 hydrogenated castor oil to fragrance oil.
  • I added 0.5 g, 1 g, and 1.5 g respectively to 24 grams of a distilled water and liquid Germall Plus mixture.
  • I mixed each tube well, then let them sit for a total of 6 days before taking pictures and then another 5 days for a total of 11. 
I've been getting e-mails and comments asking where I get my supplies...I bought the fragrance oils from Otion, the retail store of Brambleberry; the peppermint oil from a co-op last year; and the PEG-40 hydrogenated castor oil from Voyageur Soap & Candle. The containers are from Lotioncrafter (larger container) and Formulator Sample Shop (smaller, I think). 

Join me tomorrow for the initial results of this experiment!

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