topcat said:
Irishlass - so you have linked DOS to high linoleic content of oils....that is really interesting. None of my soaps are older than 3 1/2 months so I have yet to experience that wonderful phenomenon :wink:
My own assumption was that RBO has a high vitamin E/antioxidant content and was probably safe from DOS.....? How does high linoleic contribute to this please?
Tanya
Hi Tanya!
One of the best resources that I've found on fatty acids (such as linoleic acid) is this chart from another forum I'm a member of:
http://www.thedishforum.com/forum/index ... l=linoleic
From what I understand from this chart, the higher the percent of polyunsaturated fat in any given oil (which are typically high in linoleic acid) , the more delicate it is compared to soaps that are higher in saturated and monounsaturated fat.
From that, and everything else I've read, too high of a linoleic acid content can contribute to DOS. Here are at least 2 more sources that talk about not going too high on linoleic:
http://www.soap-making-resource.com/fat ... aking.html
http://www.ecauldron.net/articles/archi ... try_11.php
That just begs the question then, "How high is too high?" I've yet to find a definitive answer to that question (rats! :evil: ), which is understandable seeing as how so many variables come into play in each individal's recipe that could contribute to the development or hastening of DOS...... variables such as the other oils used in the recipe, the superfat level, the temperature soaped at, the surrounding humidity of your soaping and curing area, the freshness of the oils, and on and on.... Eeeek! :shock: I'm usually the experimenting type who would love the challenge of finding out the answer to that question, but the vast number of variables means that I'd need to find an answer for each variable, and that would just take more time and patience than I'm willing to expend.
I had a bad case of DOS once from a high amount of canola that made me quite DOS-shy (had to throw the whole batch out :cry: ), so..... I just play it safe (or take the easy way out :wink: ) by keeping my oils with higher linoleic percentages to a minimum.
Keep in mind that everyone's minimum will vary based on their own personal soaping experiences and the different variables that are present to them. Because of all these unique variables, not everyone will get DOS at the level I used my canola, and there are many who use high amounts of RBO with no problem whatsover. I'm just too chicken to at this point.
The highest I've allowed my chicken self to go since my canola disaster is 11% total linoleic combined for any given batch. I've never gotten DOS at this level, and since my soap feels great at this level I'm quite happy to stick to the shallows where linoleic is concerned because I HATE to throw away soap.
Regarding the Vitamin E in RBO, I read the study results of an experiment that was done on the Caveman Chemistry site
http://cavemanchemistry.com/HsmgDos2006.pdf where different antioxidants were added to soap to see if they prevented DOS. According to the study, Vitamin E (among others that they tested in CP soap) had no prophylactic effect on DOS in the soaps that they used in their study (see page 3 in the study). The study went on to say on page 4 that ROE and EDTA had the best preserving effects of any
single additive they used in their test, and that a
combination of BHT and Sodium Citrate did even better. Seems like the lye monster eats up any benefit that Vitamin E would normally contribute, unfortunately.
HTH!
IrishLass