Lye Percentage Discount Superfatting

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Active Member
Aug 25, 2007
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Richland, WA
The more I read the less I know.

The lye calulators I've looked at suggest a discount of 5 to 8%, but other expert soapiers like Susan Miller Cavitch and Paul talk about using 10%, 15% and even 20% (at least with certain oils such as coconut.

Please check my assumptions:

The higher the lye discount (less lye per pound of oil), the richer the the finished soap is in unsaponified fats, the less need for other fancy, expensive nutrients. High discounts result in softer, milder, more conditioning soap.

The downside to high lye discounts is the risk of the extra oil/fat in the soap going rancid or otherwise spoiling, not to mention the dreaded orange spots.
true, and the other risk is that it may not turn into soap!... you may not use enough lye...
That's why I suggested to Dan to use T-50 (Natural Vitamin E) as an antioxidant in this recipe. I use it in all my higher Oleic content oils when they arrive at my door Another natural antioxidant is GSE (Grapefruit Seed Extract) is an alternative although a bit higher in price. The 100% CO recipe with a 18 to 20% lye discount is a popular recipe right now! It will be OK to try since CO is not so prone to rancidity as other oils are.

Try a test batch of 1 pound. All you will be risking is about $3.00 in CO, lye, water, and a FO.

Paul..... :wink:
I am interested in trying that recipe in the other post for pure coconut oil soap. For preserving, what is the rule of thumb how much you use? How much vitamin e? How much GSE?
Mothi, I add about 4 or 5 drops of T-50 in my 2 pound batch of soap. When I get in a gallon of, lets say Canola, Grapeseed Oil, High Oleic Sunflower, any oil prone to rancidity I add T-50 to. I add about a soda bottle cap full size amount to the gallon of oil. It does not take too much T-50 to help against rancidity. T-50 and GSE are really not preservatives, per se, but rather antioxidants.

ETA: Knock on wood, but I have lost only 1 bar of soap in 2 years due to DOS. I have a few bars of soap that are over 1 year old and are doing just fine. I made those in Florida! :lol:

Paul.... :wink:
Thanks Paul.

Btw, is there a problem with making soap in Florida? I know it is humid and all and wonder how that affects the soap making process. For now I am in California, but will be moving to Florida in November... now I wonder...
I was just talking about the humidity levels. Humidity, I and many feel speeds up and adds to DOS! I lived in Kissimmee for 4 years and made soap in an unairconditioned DOS still in those bars. I used T-50 from day 1 though!

Paul.... :wink:
Yep Irena, ROE ( Rosemary Extract) is another great natural antioxidant to use in soap to help prevent DOS! I think the recommended usage of ROE is 1/10 of 1% of oils used in a recipe. It doesn't require much ROE for sure to help.
It is a tad pricey though compared to T-50. That is why I like T-50 myself. I started using it 2 years ago and found good luck and never tried any other natural antioxidant.

Paul.... :wink: