However, when I was digging around on the internet for something else unrelated, I stumbled across this interesting study which seems to indicate that while Vitamin E & C have many great skin benefits and can help defer rancidity in oils in general, Rosemary Oleoresin is a better performer to preserve shelf life of oils in soap. The article is written by Kevin Dunn (author of Scientific Soapmaking) and is a very interesting read: http://cavemanchemistry.com/HsmgDos2006.pdf.
Since the ROE rancidity effect appears in this one study (I am trying to find other studies which will confirm these results), I wanted to give it a shot in some soaps to test drive it a bit.
I made a 2-loaf batch of a repeat of the soap I made for the mica swirled top challenge, and added the ROE to the oils at .5% of the oil weight. However, while I was mixing the oils to trace, the ROE didn't mix in well with the rest of the soap batter. There was a layer of reddish orange stuff floating on top of the batter, even as I stick-blended it through medium trace. I didn't think to take a photo while this was going on. Now that I've re-read the articles, I have definitely over-used the ROE in my soap batter (recommendation of .02-.1%, depending on where you're reading). I also tried to soap cooler than normal - around 75 degrees, instead of my usual 110 degrees or so. Since these kind of challenges go in threes, I had also forgotten to put in the EO blend I had mixed up for this batch, so I'm going to make another batch tonight WITH the scent this time :)
What's interesting is that when the soap batter was poured, the top of the yellow layer looked pretty green. However, when I went downstairs tonight to take pictures after it had set up for a couple days, the green layer on top has gone away. It must have re-absorbed into the soap? Very strange.
|Here you can see a very slight variation of color between the top and the side. However, I had just unmolded the soap, so the color difference could be the more wet soap vs the drier top.|
|In this picture you can see the color a little, too, but the top doesn't look green like it did when it was soap batter.|
|Here's a picture of how they turned out cut. I really like these colors for the scent, even though these ended up unscented :)|
|Another show-off picture|
Here is a good blog post which looks at the anti-microbial claims of ROE and whether it can function as an effective general preservative: http://swiftcraftymonkey.blogspot.com/2012/01/essential-oils-rosemary-essential-oil_17.html (in short- it is not a sufficient stand-alone preservative system). For anyone interested in cosmetic chemistry knowledge, Susan's blog is a great resource, and has some excellent starting recipes for lotions, shampoos, etc.
I've been researching what happens if one uses too much ROE in soaps, but I'm not finding a ton of information. This soap will be relegated to personal use until I can determine whether it is safe to use.
Also, I had a friend over a few weekends ago to help me take some pictures and show me how to use my little old point-and-shoot. She took some amazing pictures with the natural sunlight, and she showed me some good ways to set up and use my camera, too. I'm so happy with how the pictures turned out!
|Some Chocolate Mint cupcakes - they look like edible cupcakes!|
|The Challenge #3 soap - mica swirled tops|
|Yuzu / Orange soap|
|Soap Challenge #2 - Elemental Swirl|
|This one I took myself :) Rosemary Mint. It looks similar to the ones my friend took with her SLR camera, even though you can tell hers are better.|
Have a great Monday!