Trouble with Superfatting

by Ira

I am having trouble figuring out the superfatting amount. I made my first soap but it seems I got it wrong.

I used soapcalc and I put 5% in for the superfat. My recipe was castor, palm, olive, coconut and I put my castor amount to 5% and I added it at trace.

So... now I read everywhere that I shouldn't add it at trace but put it with my other oils.

Help me to figure it out how much superfat am I have now?


Understanding how the superfat works can be confusing, especially since the process has evolved over the last decade or so and information on the web varies.

If you put the 5% superfat amount into Soapcalc and just held back that amount of Castor oil until your soap reached a light trace, your soap should be alright as long as you mixed it in well.

You do not need to do this in the future though. When you enter the superfat amount into Soapcalc, the program will reduce the amount of lye needed which then leaves your soap with 5% unsaponifed oil. Setting the amount in Soapcalc is all you have to do.

Adding the oil later does not change how much oil will be left unsaponified. The saponification process continues after the soap has been poured into the soap mold so any lye still looking for oil to bond with will find it then.

One problem with adding oil after the soap traces, is that people tend to add more oil than what is in the recipe which will increase the superfat. This isn't bad if you only add a little oil but if you add quite a bit, you can end up with an oily soap.

Hope this clears it up for you,


Comments for Trouble with Superfatting

Average Rating starstarstarstarstar

Click here to add your own comments

lost again
by: Anonymous

Do I add the oil in addition to the total oils or deduct the 5% from the total oils and then add back what oil I want to use or do I add the superfat oil in the master formula on soapcal? I feel dumb as a stick.

Selecting the Super Fat Oils
by: Randy Cox

I understand the whole concept of reducing lye to have "superfat." But what if I make a soap recipe--any old recipe--with NO discount.

I want every bit of oil to be bonded with lye. But then, as late as possible at/after trace, I want to add in some raw coconut oil for both moisture and scent.

I want most of my "superfat" to be that coconut oil, not whatever else was in they recipe (like, say, smelly olive oil).

If I added everything up front, I'd get a bunch of oils (everything in my recipe) left over as the superfat, and I really don't want that.

How can I ensure that most/all of my additional oil will be unsaponified?


If you are making cold process soap do as you've said, hold the superfat amount until the last possible moment and add it then.

Since saponification continues while in the soap mould, adding it last may only ensure that most of your superfat is the oil you added last.

If you want to make sure that all of your superfat is the oil you have selected, use the hot process method and add the superfat after the cook just before placing the soap into the mould.

With the hot process method, saponification is complete once the cook has finished.

Hope that helps,

hi Ira
by: Anonymous

From your list,
Your soap is oversaturated with oil.
Do you know why?
You plugged in 5% as superfat.
The calculator goes ahead and reduces your lye. Your lye is already reduced whether you remove the castor oil or not at this stage. But still you did remove the castor oil, in an already reduced lye formulation that makes the formular superfatted already, and added 5% of castor oil at trace!
Removing your Castor oil has not change the formular that the calculator used in calculating. The calculator is not aware you removed your castor oil. It's been superfatted. So your soap must be TOO soft have have orange spots. To get the value of 5% castor oil, it's: (5/100)* the value of the total weight shown at on soapcalc.

100% coconut oil - Suerfat %?
by: Anonymous

Hi, I was reading about superfat %. I get the concept, but how do I decide the superfat %? I use 5 - 8% superfat in my soaps. I was planning on making a 100% coconut oil soap and also salt bars. The recipe(s) suggests 20-30% superfat. Please explain. Thank you very much - Sue

Thank You!
by: Anonymous

Goodness, I too was tripping over the whole superfat thing, but suspected it was just as you explained, and not a separate addition at some other time. I just read it as Soapcalc had equated it, and I just needed to acknowledge it as "done". It was just that one thing that made me a bit

Thank you
by: ira

hm...ok. Yes, I understand it all. Thank you very much for the explanation

Still confused
by: Ira

Yes, I understand that the whole thing with adding oil at trace in CP doesn't matter but since I've done it I wanted to figure it out what is the % of superfat that I've used. I think this % is 5.767% instead of 5%. The difference came from the different Sap values of the oils. I would done it right if I just put the Castor in the beginning with the other oils. But no, I write my recipe like this: Super Fat - 5%
Castor- 40g (5%)
Coconut oil- 240g (30%)
Olive oil pomace- 320g (40%)
Palm oil- 200g (25%)
And Soapcalc calculate for me Lye- 114.366g

But then i decided to mix in the beginnig only coconut, palm and olive. But the lye needed to fully saponify them is not 114.366g because of the different Sap value. The lye to saponify them 100% is 115.251g. So need 0.885g more. And 0.885g are 0.767% non saponified oil. So with my castor of 5% at trace and this 0.767%- I've got in the finish soap superfat of 5.767 %.
Isn't that right?


Whether you add the 40 grams of Castor oil at the beginning or at the end will not change the amount of superfat you have in your recipe.

If you added all of the ingredients as you have listed above and in the amounts you have listed above, you will have your 5% superfat.

Superfat is the amount of leftover oil after the lye has saponified completely. Saponification continues to take place after you have poured your soap into the mold. If there is lye still unsaponified when you add your castor oil at trace, the lye will find it and turn it into soap.

Your superfat will only change if you add more or less oil than what you have calculated in the recipe.

SAP values represent the amount of lye needed to saponify a given amount of oil. This has been figured out by SoapCalc for you already and will not change by adding the castor oil in later.

Hope that makes more sense now,

Click here to add your own comments

Return to Submit a Question.

Like This Page?