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Super-fatting - what it is and how to do it appropriately

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RogueRose

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I'm kind of confused about how superfatting is calculated and done. I've seen lye calculators that have an area to input SF % and then amounts of oil (in % - must equal 100). So if you want to make 5% SF and you want 35% CO, 35% OO and 25% lard, 5% castor, & you plan to use 500grams of oil, the only difference between 5% and NO-SF is the amount of lye used.

Superfat comparison picture


Method 1
I've read that people mix all the oils then add lye water and then EO's at some point prior to trace.

Method 2
I've also read of people mixing 95% of the oils (maybe in this case leave out the castor, or Kokum butter in another recipe) with they lye water and when it gets close to trace add in the castor or Kokum butter & EO's. This way you are garunteed to have a specific fat non saponified.

I'm wondering if one way is better than another or better for a specific purpose. Is there any harm in either of these methods?

Is there a better way to clear this up/explain the process or are the above methods proper?
 

Dorymae

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When you are using a lye calculator with a specific "super fat" percent, what you are actually doing is lye discounting. The amount of lye is reduced to give you a portion of oils that will not be saponified. "Superfatting" is when you add extra oil to a recipe to achieve the same thing - that is a percentage of oil which is not saponified. The oil that is not saponified is called super fat in both cases.

In lye discounting you add the lye to all the oils and add your additives (fragrance, color, etc) after the lye and oils are fully mixed.

In Superfatting you add the lye to your oils bring it to emulsion then add your additives and extra oil for super fat.

Hope that helps.
 

CanaDawn

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?? I have never heard superfatting being only adding it after trace/emulsion. It's always discussed how lye doesn't pick and choose which oil it uses up, even at trace, and superfatting and lye discounting are pretty much equivalent, aren't they? Just differ in how you think about the calculation?
 

jade-15

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Method 2 is false, you cannot guarantee having a specfic fat non saponified using cold process.
Using cold process, it doesn't matter when you add your 'superfat oils' - they will still be equally saponified so you cannot selectively keep one type of oil for a superfat. So you may as well save the effort and just throw it all in at the start, using the 'lye discount' instead. From what I've picked up on the forum, superfat and lye discount are used somewhat interchanagebly... but it's probably more accurate to talk about a lye discount when doing CP.

In hot process, you CAN add a certain oil after the cook (saponification) and it will non saponified.
 

IrishLass

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Right here, silly!
Method 1 in your post refers to lye discounting, while Method 2 refers to a form of superfatting, although the belief that one can hold back some oils and add them at trace and have them remain unsaponified has been debunked quite soundly by the work of Dr. Kevin Dunn in this article here:

http://cavemanchemistry.com/LyeDiscount-Dunn.pdf .

It can all be very confusing, I know, and many people look at both terms (lye discounting/superfatting) as referring to the same thing, and in a certain sense they are, at least in terms of the finished soap having an excess of fat in it, but technically, there is a slight difference between them in terms of the method used to end up with the fat excess.

When lye discounting (using SoapCalc), it's as you say- the complete tally of the percents of all your oils in your batch should equal 100%, and the calculator will figure out the lye amount for your batch based on the SAP #'s and the amounts of your chosen oils, plus whatever numerical percent that you type into the superfat box.

The particular superfatting method that you mentioned in Method 2 is no longer considered to be a valid method, based on Dr. Dunn's work. While one can still use a superfatting method to give their soap an excess of fat, they cannot control/guarantee which fat will get saponified and which one won't. Unfortunately, it just doesn't work that way in reality. The closest that one can come to having that kind of control is to HP their batch, and then add superfatting oils into the batter after the cook, i.e., when the soap no longer zaps.


IrishLass :)
 

RogueRose

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Thanks for all the replies and explinations! I think when I was explaining method 2 I was remembering reading SF'ing in hot processing. I was totally inexperienced when I read this so that is probably why I didn't know the difference. It really isn't that difficult to understand once the saponification process is understood.

So to be clear, when the mixture reaches trace in CP, the saponification process has still not competed but in HP'ing when the soap is poured into the molds the saponification process has finished or at least very close to being finished? Is this an accurate description?

So if someone wanted a specific fat to be left unsaponified the only option is really HP or possibly rebatching (if rebatching would allow this process).?
 

jade-15

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So to be clear, when the mixture reaches trace in CP, the saponification process has still not competed but in HP'ing when the soap is poured into the molds the saponification process has finished or at least very close to being finished? Is this an accurate description?
Pretty much. Trace is (to my basic knowledge!) just the beginning of the reaction - you have forced the oils and lye to mix together properly (emulsification is the step immediately before trace) and now they are beggining to react. This is why you need to wear gloves and safety equipment whilst pouring and swirling the soap.
During HP, you zap test to ensure it has finished "cooking" (saponifying) and you could (theoretically) use it immediately (it does improve with a cure though).

So if someone wanted a specific fat to be left unsaponified the only option is really HP or possibly rebatching (if rebatching would allow this process).?
Yep. Rebatching does allow that process - it's what I've done with some soaps I didn't like (too much coconut oil = way too drying).
I have HP'd a facial soap so I could use 10% jojoba oil as a superfat, since it's so good for the face... to be honest, I cannot tell a difference. I'm pretty sure most of it is washed off with the soap - I still have to use moisteriser afterwards or my face is far too dry.
 

The Efficacious Gentleman

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Jade put it brilliantly - Trace is where the batter is mixed enough that the reaction is beginning, but as it takes at least 24 hours to complete, we can get a sense of how incomplete it is after these few moments of getting it to trace - we really are at the very start of the reaction when we pour CP in to the mould. With HP you mould it up when it is fully saponified.

As for rebatching, as this is usually a form of HP I don't see why one would CP a soap with a small lye discount and then rebatch it to add a specific super fat. Why not just HP it from the start and save a lot of effort.......................?
 

The Efficacious Gentleman

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I forgot to add something on the Superfat/lye discount idea.

There was a thread a while ago that looked at putting in extra oil after the cook in HP and how to work out how much. There we realised that a lye discount and a superfat are quite different -

lye discount - the total lye required to fully saponify the oils is reduced by a percentage, leaving some oil unsaponified. As 100% of the lye would saponify 100% of the oil, a 5% reduction in lye would leave 5% of the oil unsaponfied, or superfatted.

Superfat - the percentage of oil not saponified in a soap.

In CP these two are one and the same, but in HP you can add more oil once all of the lye is gone and here is where it gets tricky...................

A lye discount is based on how much lye is needed for the oils. As we know, not all oils need the same amount of lye to saponify. So if I HP a batch, 95 grams with a 0% lye discount (super accurate measuring, of course) and then add 5 grams of oil at the end, I have 5% superfat, as 5% of the oil is not saponfied (5 grams out of 100 grams is 5%) but what I may not have is a 5% lye discount -

If my superfat oil added in after the cook needs more or less lye per gram than the oil mix I used for the 95 gram batch, then I have a 5% superfat but maybe a 4% or 6% lye discount, or maybe more, depending on the oils used. In this instance it is not right to talk about a lye discount, unless you work it out specifically, but rather a superfat is a more accurate term.

I have look over this a few time and hope it makes sense to others and not just me!
 

Susie

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Comprehension check

OK, I am checking my comprehension thus far, NOT giving explanations, got it? Me + Math = pending disaster(usually).

Am I correct in the following?

If I made a 0% superfatted lard soap of 500 g, I show that I need 70.58 g of NaOH. If I were superfatting with 5% lard, I would add an additional 25 g of lard at the end of gel for a total of 525 g lard. Right?

If I were making a lye discount of 5%, I would use 500 g lard and 67.059 g NaOH.(Used Soapcalc.net)

Now, if I were making a 500 g lard soap with 0% superfat, and added 5%(25 g) jojoba oil, I would actually end up with more on the order of 12% superfat, as the SAP value of jojoba oil is 0.66 compared to lard at 0.141. Is this correct?
 
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The Efficacious Gentleman

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The maths also gets funky when we look at adding 5% of the oils as a 5% superfat. We'll use a more extreme example to get the maths clearer.

50% of 100 is 50. So if we took 100grams of oils and added 50 grams after the cook, we'd have a 50% superfat, right? Well, not really, as the superfat is the % of the total oils that is not saponified. Because we have a total of 150 grams of oils, 50 grams of which is not saponified, we have a 33.3% superfat.

In your example, we would make a 475g lard soap and then add 25g at the end. That would mean that 5% of the total oil weight (500grams) is unsaponified. Adding 25 grams to the 500 gram pot gives you a 4.7% superfat as 25 is not 5% of 525.

With the lye discount, I haven't check the numbers, but aye, it's less lye than needed.

With the last point, I don't follow - is that CP or HP? Do you mean that by adding 5% Jojo at the end gives us a 5% superfat but a 12% lye discount?
 

Susie

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And this is why I am checking comprehension...because I really don't get math.

I understand what you mean about the superfat being 4.7%. I don't understand how you got to the other numbers, but that just may be my brain not wanting to do math, so I will let that percolate a bit before re-addressing it.

On the jojoba oil, I was trying to figure out how you would know how much superfat you were adding if you added a vastly different SAP value oil as superfatting, but since I don't really get the math on the first part, this point is beyond my comprehension at this time.

I may want to mention at this point that I passed college algebra, which was mandatory for graduation, because the professor knew how hard I had worked all semester, and was kind enough to give me the one point required for a passing grade if I promised not to take any higher maths. So, don't feel bad if this never clicks in my mind.

Thanks, though!
 
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The Efficacious Gentleman

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I do feel bad that this is in a beginner thread, but it is an interesting distinction.

The trick is to look at your total batch size, including superfat (talking HP here) and work backwards. So if you have a 1,000 gram mould (working in metric as it is easier) and you want to do a 5% superfat, you would make a 0% lye discount batch of 950 gram and then add in 50 grams after the cook as superfat, giving you your 1000grams with 5% being unsaponified.
 

Susie

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Oh! Got it!

Thanks!

(Completely feel like an idiot now...)
 

Susie

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Yes, I remember. And I am still trying to get this. It just may take a while. And you give me hope that I will eventually get it.
 

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