Can anyone explain the "Superfat % should be 1/2 of the Cleansing number" rule?

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DeeAnna

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In the past year or so, I have seen more and more people advise others that the superfat percentage should be half of the Cleansing number. FOr example, if Cleansing is 10, then superfat % should be 5%.

Can anyone point me to any resources that explain the rationale behind this advice?

I can easily think of many successful soap recipes that break this rule based on my experience as well as what other experienced soap makers are doing. So I'm not sure this advice makes a lot of sense, even as a temporary rule-of-thumb for beginners to follow.

But maybe I'm missing something. I'd like to learn what y'all think about this and why. Your thoughts?
 
Cleansing # as calculated by... which source?
Ah, good point.

From the context of the advice, it seems that the advice-givers are using the "cleansing number" as calculated by Soapcalc. Equal to the combined percentages of lauric and myristic acids.

All the other online recipe calcs I've seen that provide a "cleansing number" appear to calculate it the same as Soapcalc. But maybe there are others I haven't encountered that handle this differently.
 
I don't use "Cleansing #'s" nor Soapcalc, so I have no idea, but it does sound made up. And the idea that there's one best formulation for everyone is silly. I hate Castile/ bastille at whatever s/f, for example, but many love them.
 
So I'm not alone in being skeptical and puzzled.

The usual default of 5% superfat seems to me to be a more useful starting point for most recipes. A 5% superfat starting point has fewer exceptions to the rule than this other idea.

For example, the "1/2 of cleansing" rule would say we should be using a superfat of 33% for a 100% coconut oil soap, rather than the 20% superfat that many people use. It would say one should use zero superfat for a 100% olive oil soap. Neither makes sense to me.

And, yes, Ali -- even for a more middle-of-the-road recipe, it's going to call for more than double the superfat than the 2-3% that you and I use.
 
I agree that a rule for cleansing and superfat sounds made up and wouldn't guarantee good results.

However, I guess I have always believed you can offset some of the harshness of a high cleansing number with a higher superfat. Isn't that a reason for a high superfat on a 100% cococnut oil? Granted, you are decreasing lather and increasing soap scum so we all wouldn't agree on it being a better soap. I don't adjust the superfat for my goat milk soaps. I have always wondered if they were popular because they really are a higher superfat of my soaps with water because of the uncalculated amount of milk fat.
 
I base my super fat on my cleansing number but I don’t have a set calculation for it. If I use 15% coconut oil I use 3% super fat, but it’s not a hard a calculation. I just figure the lower the number the less super fat I need and a higher super fat would translate to less bubbles. My 25% coconut oil soap has a super fat of 8% and I absolutely 💗 it. I get great lather and I don’t notice a lot of soap scum with the recipe and neither do my friends. It’s my most popular recipe too.

Basing super fat on half the cleansing number alone is very silly to me and I don’t like that rule as my 15% coconut oil recipes would be terrible at a super fat of 7.5%. There’s no need to go that high. I like the standard 5% in calculators and then going up or down from there to your liking.
 
Sounds like a silly guideline to me. Unless I am making salt bars my average superfat is 2-3% My cleansing runs from 13-17% and my bars are very far from cleansing. I was low superfatting long before it was considered acceptable, by many and was told so by a few members who are no longer in the forum.
 
I'm not near my recipe book, but know my soaps are on the low cleansing side, probably 10-14 at the most. Long ago I dropped my SF to 2% due to the soap scum AND advice here from several who said the old pipes in my house would love less soap scum too. So most of my soaping life has been with low SF. I've never come across that % advice and wouldn't pay attention to it anyway. But this is the only soaping forum I read with any regularity, and don't know why this title caught my eye. As I age, I can guarantee that my own pipes (legs) love the 2% SF, too....I hate scrubbing soap scum off my bath tub and shower walls. I'd never go back to even 5%SF
 
So I'm not alone in being skeptical and puzzled.

The usual default of 5% superfat seems to me to be a more useful starting point for most recipes. A 5% superfat starting point has fewer exceptions to the rule than this other idea.

For example, the "1/2 of cleansing" rule would say we should be using a superfat of 33% for a 100% coconut oil soap, rather than the 20% superfat that many people use. It would say one should use zero superfat for a 100% olive oil soap. Neither makes sense to me.

And, yes, Ali -- even for a more middle-of-the-road recipe, it's going to call for more than double the superfat than the 2-3% that you and I use.
I think it’s a bit of a guideline not a rule. And we all love to break rules. I’ve tried increasing the superfat on Coconut/salt bars, but 30% was just too high. So I use 20%, even though it’s not half the cleansing number. A lot of newer soap makers don’t understand the fatty acids, and want rules. I think experience is the best teacher.
 
The typical default of 5% superfat used by many soap recipe c@alculators is an even simpler and easier rule for beginners to follow than this "1/2 rule" we've been discussing in this thread.

If a beginner uses a 5% superfat for their soap recipes, they'll get better results for a wider range of soap types. And the exceptions to the 5% superfat rule are few and well defined -- basically soap formulations that are higher in lauric and myristic fatty acids than is typical, such as soap that is rich in coconut oil. This "1/2 rule" has enough exceptions to the rule that it simply doesn't make sense.

I'm aware there are trends in superfatting that vary with time and location. For example, when I first joined this forum and a now-defunct forum called The Dish, I think the most common superfat mentioned was in the 5-10% range. Since that time, the idea of superfatting a mild soap even lower -- typically 2-3% -- doesn't get nearly as many horrified reactions as it used to. :)

Another trend I've heard about is superfatting soap at 15% or higher, even for mild recipes. My recollection is this is a common practice by some European soap makers. I'm not informed enough with this practice to know if they adjust the superfat % based on fatty acid content or just use a consistent high superfat regardless of recipe. Maybe someone else knows?
 
The typical default of 5% superfat used by many soap recipe c@alculators is an even simpler and easier rule for beginners to follow than this "1/2 rule" we've been discussing in this thread.

If a beginner uses a 5% superfat for their soap recipes, they'll get better results for a wider range of soap types. And the exceptions to the 5% superfat rule are few and well defined -- basically soap formulations that are higher in lauric and myristic fatty acids than is typical, such as soap that is rich in coconut oil. This "1/2 rule" has enough exceptions to the rule that it simply doesn't make sense.

I'm aware there are trends in superfatting that vary with time and location. For example, when I first joined this forum and a now-defunct forum called The Dish, I think the most common superfat mentioned was in the 5-10% range. Since that time, the idea of superfatting a mild soap even lower -- typically 2-3% -- doesn't get nearly as many horrified reactions as it used to. :)

Another trend I've heard about is superfatting soap at 15% or higher, even for mild recipes. My recollection is this is a common practice by some European soap makers. I'm not informed enough with this practice to know if they adjust the superfat % based on fatty acid content or just use a consistent high superfat regardless of recipe. Maybe someone else knows?
I have seen this in FB groups. European soapers tend to superfat at high percentages. And there’s a well known soaper who uses 7% no matter what. I adjust my superfat based on my recipe.
 
I generally superfat at 3%. My high butter recipe I do 2%. My soap is not at all drying. I’ve seen the 1/2 cleansing # rule on Facebook groups. I generally just keep scrolling past those posts and comments as I don’t like how people get into it with each other. If they want lots of soap scum and possibly clogged pipes have at it. I saw one person who posted about her pipes being clogged and her plumber told her it was because of the soap scum and many people said that was not true and that they routinely super fat at 8 to 10% and never had a problem. Ugh! I just rolled my eyes and moved on. I’ve learned so much from this forum and it is my go to for trusted information. ♥️
 
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I saw one person who posted about her pipes being clogged and her plumber told her it was because of the soap scum and many people said that was not true and that they routinely super fat at 8 to 10% and never had a problem. Ugh! I just rolled my eyes and moved on. I’ve learned so much from this forum and it is my go to for trusted information. ♥️

Just because you never have a problem doesn’t mean that others won’t. I have never had a problem with my plumbing at 8% super fat but I know it can happen. I do add a chelator to help reduce the amount of soap scum and hopefully prevent clogged pipes for others. People are set in their ways. Soaping is science. When learning how to soap any advice I read had to make sense to me. This new super fat rule makes zero sense to me.
 

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