10% SuperFat After Cook - Hot Process

[pschoe]

Hi you All,
I would like to make a recipe with 10% Apricot Oil as my superfat.
My question is:
Do I add all my oil including the apricot to the lye claculator with 0% superfat?
Then
I will keep the 10% Apricot oil separately to add after the cook?

Will all the lye be gone? Or will I still have acrive Lye because I took the 10% oil out?

Thanks for your help and advice - I appreciate it.

 

[Obsidian]

No, you want to add all your oils with 10% SF to soapcal. Save out the 10% to add after the cook.

 

[pschoe]

No, you want to add all your oils with 10% SF to soapcal. Save out the 10% to add after the cook.

Thanks - Luckily I've come back to see if someone answered I was just about to add my lye I had to dump my lye solution - when I added the superfat it made the lye amount lower - thank you so much - I think you just saved me from a huge disaster

 

[Obsidian]

It wouldn't have been a disaster but it would have been a 0% SF soap.

 

[Rune]

No, you want to add all your oils with 10% SF to soapcal. Save out the 10% to add after the cook.

I don't think that will be correct. If you add the apricot oil to the lye calculator and use 10% superfat, for so to take the apricot out and save for after the cook, the saponification value of the total batch will not be correct since the apricot is included, an oil that is not used to make soap. Let's say you make a 100% coconut oil soap with apricot oil as superfat. If you include the apricot oil in the lye calculator for so to take it out, it will lower the total saponification value. So your superfat will actually be over 10%.

The correct way is to put your oils that are going to be soap in the lye calculator - all your oils but except the apricot - and use 0% superfat. Then you measure out the apricot oil. 10% of your soapmaking oils. Let's say you use 400 grams of coconut oil and 800 grams of olive oil in your soap. That is 1200 grams in total. So you have to measure out 10% of that - 120 grams of apricot oil, and set aside as superfat. Then you will have approximately 10% superfat in your soap (your oils does not necessarily have exact the same saponification value as the lye calculator tells, so it might not be exact 10% superfat, but as close as you can get).

 

[earlene]

I don't think that will be correct. If you add the apricot oil to the lye calculator and use 10% superfat, for so to take the apricot out and save for after the cook, the saponification value of the total batch will not be correct since the apricot is included, an oil that is not used to make soap. Let's say you make a 100% coconut oil soap with apricot oil as superfat. If you include the apricot oil in the lye calculator for so to take it out, it will lower the total saponification value. So your superfat will actually be over 10%.

The correct way is to put your oils that are going to be soap in the lye calculator - all your oils but except the apricot - and use 0% superfat. Then you measure out the apricot oil. 10% of your soapmaking oils. Let's say you use 400 grams of coconut oil and 800 grams of olive oil in your soap. That is 1200 grams in total. So you have to measure out 10% of that - 120 grams of apricot oil, and set aside as superfat. Then you will have approximately 10% superfat in your soap (your oils does not necessarily have exact the same saponification value as the lye calculator tells, so it might not be exact 10% superfat, but as close as you can get).

I disagree, Rune. If all oils are included in the lye calculator, it doesn't matter whether any oil is held out to add later. The lye will only interact with 90% of the oils. If you hold out some oil and add it after saponification, then still only 90% of the oils had a chance to interact with the lye. If you hold out the wrong amount of oil and had a bit of excess lye in the pot before adding the 'held-out' oil, any left over lye in the pot will still interact with whatever oil is then added to the pot at the end.

So the end result would still be the same. Given that the lye calculator is assuming the lye was 100% pure, which is highly unlikely in the first place anyway. But if it were and all the measurements were totally accurate, then the goal of 10% SF would be the end result, no matter how the oils are added.

 

[DeeAnna]

I respectfully disagree with you also, Rune. Earlene is spot on correct.

I want to point out a not-so-obvious fact about the "superfat" setting (more correctly called the lye discount setting.) It does not necessarily mean 10% of the fat is left unsaponified. It's means you are using 10% less NaOH by weight to make the soap. There is a difference.

Remember that we work in units of weight, but saponification is all about molecules. If there are more molecules stuffed into a gram of fat, that gram needs more NaOH to saponify all those molecules. A 10% lye discount -- 10% less NaOH -- will not necessarily mean 10% of the fats by weight will remain as superfat.

The only time a 10% lye discount (10% less NaOH) translates to a 10% superfat (10% of the fat is unsaponified) is when the saponification values for the fats are all about the same. Or if you're making a single oil soap (100% olive for example).

What does that mean in a practical sense? Follow Earlene's advice and don't worry about it. The NaOH will take what it wants, so if you have provided a little less fat at the start than the NaOH wants, it will saponify some of the fat you add later. Regardless, it will all come out right in the end if you do the calculations properly.

 

[Rune]

Sorry that I forgot to answer. Thank you for letting me know that a 10% lye discount is not the same as 10% superfat. I should have known, since I knew that the superfat is a lye discount. But did never think of it that way. Probably because SoapCalc makes you put in a superfat percentage, so I just assumed.

I tried to put both methods in SoapCalc, choosing a 100% coconut oil soap with apricot kernel oil as superfat. Coconut to really see if there is a difference, since coconut has a much higher sap value than apricot kernel. The method with 0% superfat/lye discount and 900 grams coconut, gave a lye amount of 164,92. And then 100 grams of apricot would be added after the cook.

The other method, with 900 grams of coconut and 100 grams of apricot and 10% superfat/lye discont, gave a lye amount of 160,94.

So 4 grams difference between the two methods. But, in real life, it would probably not be a significant difference, if any at all, since a well balanced recipe would be much closer in sap value to the apricot than a 100% coconut soap.

I still think that if you include the apricot in the recipe and use 10% superfat to calculate lye, it will be calculated as if you made a soap with 90% coconut and 10% apricot, and with a superfat of the exactly the same - 90% coconut and 10% apricot. When you actually makes a soap of 100% coconut and adds 100% apricot as superfat. So the sap value makes the difference. The closer the soaping oil and the superfat is in sap value, the smaller the difference. I think that will be correct. But I'm not totally sure. Since you two have tons of experience and knowledge, I'm probably wrong. I will chew on it some more, and see if I can understand it.