Superfatting

[My Mountain Soaps]

Ok all you wonderful teachers, I am still learning. I want to know about superfatting.
1. What exactly is it?
2. How do i determine what percent superfatting to use? for example if you follow my thread http://www.soapmakingforum.com/showthread.php?t=39423 "I now have deer and elk tallow" you will see that i am about to venture into making my first batch. Just for learning experience, i took the recipes that Obsidian and others were so kind to give me, and ran them through soap calc. But when it asked for superfatting percentage, i wasnt sure.
So i would appreciate any instruction/insight you may have on this topic. A friend told me that she used 8% on her soaps, but i never got around to asking why she chose 8%. so if you will please answer my two questions, i would greatly appreciate it!

 

[Andrea]

I don't know if I'm 'qualified' with enough experience to answer this properly for you but here's my understanding of it:

Superfatting is essentially adding more oils to your batch than your lye will be able to saponify. So the goodness in those oils will be in your soap when it's finished curing.

Bad point of superfatting seems to be that because the oils haven't turned into soap there is a chance of them going off quicker.

I'm sure you'll get much more edu-ma-cated advice than this but I thought I'd give you my two cents, everyone has been so helpful to me and I'm trying to help when I can!

 

[shunt2011]

Superfatting is having extra oils that are not saponified by the lye. I generally superfat 8-10 percent and on my mostly coconut oil soaps I superfat at 20%. I have never had a batch get DOS or go bad on me in three years. Older more mature skin is an example of skin that may need a higher superfat (Me) or those with more sensitive skin may prefer a higher superfat as well.

 

[My Mountain Soaps]

well, atleast now i understand the principle! thanks for edu-ma-cating me!!!! ha ha.

 

[dagmar88]

Bad point of superfatting seems to be that because the oils haven't turned into soap there is a chance of them going off quicker.

Not really;

Is It The Lye Discount (Superfatting)?
It is sometimes asserted that an excessive lye discount causes orange spots. We therefore made two soaps identical to
our standard soap except that in one case the lye discount was 10%, in the other, 0%.
From the color saturation curves in the two following graphs, we can see that, indeed, the 10% discount soap does
eventually become more orange than the 0% discount soap. But looking more closely we also see that the induction
period is about the same, 75 hours.
Even at 0% discount the soap becomes noticeably orange in about the same time as at 10% discount. Since our goal
is to prevent orange spots altogether, we should not look to changing lye discount as a cure for them.

http://cavemanchemistry.com/HsmgDos2006.pdf




You need to superfat. Sap values are averages, so at 0%, you could actually end up with lye heavy soap.
What percentage you like in that particular recipe, is a matter of trial and error.
Generally, the more cleansing the soap is, the more superfat it needs not to strip your skin too much.
For example, 100% coconut soap works well with a 20% superfat.

 

[lizflowers42]

Also, since most of us don't have the fanciest scales (most box stores sell one that convert grams/ounces with 1 or 2 decimal points), it's a good idea to round up your oil, and round down your lye.

 

[pamielynn]

I always find it easier to think of it as a "lye discount" rather than "superfatting". Work with the oils you have: 100% olive and subtract 5-8% from the NaOH amount -don't ADD to oil amount.

I typically discount up to 8% if it's a recipe with a higher amount of "cleansing" oils - down to 5% for a softer, less "cleansing" recipe. Some people routinely discount at 6% and go up to 8% in the wintertime to try and counteract any dryness of the skin.

The best thing you can do is to make a couple of identical recipes at different discounts and see if you can tell the difference.

 

[Andrea]

Oh! Okay, sorry I don't know where I read that but what you've posted is interesting! I've generally been superfatting at 3% (I think based off a recipe I first tried from Soap Queen) but have also tried a 6%. Really good to know about the cleansing / superfatting relationship!

Thanks for posting that!