What increases "longevity"?

[JillGat]

My soap recipes, when entered into the SoapmakingFriend calculator, often show the longevity property to be lower than 25. Which ingredients improve longevity and hardness of the bar? Which ingredients slow down trace? I've seen a couple of charts that give conflicting info on this... does anyone have a quick guide that they use? (I know about bubbly lather vs conditioning) Here is my recipe:

Olive oil 23
Rice Bran oil 8
Castor oil 5
Coconut oil 24
Lard 32
Shea Butter 8

I will be doing a design, so won't add sodium lactate to the lye water this time, because I don't want it to trace too fast. I am adding sodium gluconate to the water before the lye, though.

Thanks!

 

[AliOop]

Palmitic and stearic FAs will contribute to more longevity. Look for fats that contain more of those.

Lard and OO are slow tracing. I'd say tallow and some other soft oils are in the medium range.

All butters, castor oil, and RBO tend to speed up trace, along with heat, stick-blending, clays, AC, and to varying extents, lower water.

I've never experienced sodium lactate speeding up trace. In fact, it's used in hot process to keep the soap fluid longer.

 

[DeeAnna]

Also "soy wax" which is hydrogenated soybean oil is high in palmitic and stearic fatty acids.

 

[akseattle]

@JillGat , I have been walking around in circles for the last couple months trying to tweak my recipe to increase hardness and longevity. I was stuck at 26 to 27 on longevity. I wanted to get in up to at least 30. About 10 days ago, I decided to try stearic acid. Posts and threads here and elsewhere on the internet recited a real parade of horribles when using stearic acid so I asked this forum for guidance on using stearic acid.
Even 1% Stearic acid did immediately bump up my longevity number.
As it turns out, stearic acid really isn't that big of a deal to use. But, after some discussion, i realized that 1) stearic acid brings longevity and hardness, but it doesn't bring that much else to my soap. And 2) there are other oils that will increase hardness and longevity, but will also bring another property I like.
I realized that for my recipe, the easy way to increase hardness and longevity was to increase the lard. That of course, meant I had to give up some of another oil. I have limited coconut oil in my recipe to 20% for soap that I might use because I have fairly dry skin. I hated to reduce the % of olive oil because-- well, because I'm attached to olive oil.

So, you could try stearic acid- for an immediate increase in hardness and longevity. OR, an easy way is to increase the lard in your recipe, and reduce one of the other oils that you think you can reduce without a huge impact to the properties you like.

I've also been adding a teaspoon of salt per pound of oils. That is supposed to increase hardness. I'm reasonably new to cold process soaping so I can't say based on experience if the salt does or does not make a difference. I'm just trusting that it does because everyone says so!

Below is a link to a great article from Modern Soapmaking
What Fatty Acid Profiles in soapmaking are the Most Popular?

https://www.modernsoapmaking.com/blog/the-most-popular-fatty-acid-profiles-in-soapmaking

@DeeAnna also has a good blog/ post on her website Classic Bells "What do the SoapCalc numbers REally mean? i found it really helpful when I started trying to increase hardness and longevity, and generally to come up with a well-rounded recipe. That link is:
https://classicbells.com/soap/soapCalcNumbers.asp

Ditto on what @AliOop said about lard. I have found it to be slow moving. So, increasing your lard will probably also give you a little more time to work on your design.

Good luck! Let us know if you come up with a harder, long lasting bar that has all the other properties you like!

 

[JillGat]

@JillGat , I have been walking around in circles for the last couple months trying to tweak my recipe to increase hardness and longevity. I was stuck at 26 to 27 on longevity. I wanted to get in up to at least 30. About 10 days ago, I decided to try stearic acid. Posts and threads here and elsewhere on the internet recited a real parade of horribles when using stearic acid so I asked this forum for guidance on using stearic acid.
Even 1% Stearic acid did immediately bump up my longevity number.
As it turns out, stearic acid really isn't that big of a deal to use. But, after some discussion, i realized that 1) stearic acid brings longevity and hardness, but it doesn't bring that much else to my soap. And 2) there are other oils that will increase hardness and longevity, but will also bring another property I like.
I realized that for my recipe, the easy way to increase hardness and longevity was to increase the lard. That of course, meant I had to give up some of another oil. I have limited coconut oil in my recipe to 20% for soap that I might use because I have fairly dry skin. I hated to reduce the % of olive oil because-- well, because I'm attached to olive oil.

So, you could try stearic acid- for an immediate increase in hardness and longevity. OR, an easy way is to increase the lard in your recipe, and reduce one of the other oils that you think you can reduce without a huge impact to the properties you like.

I've also been adding a teaspoon of salt per pound of oils. That is supposed to increase hardness. I'm reasonably new to cold process soaping so I can't say based on experience if the salt does or does not make a difference. I'm just trusting that it does because everyone says so!

Below is a link to a great article from Modern Soapmaking
What Fatty Acid Profiles in soapmaking are the Most Popular?

https://www.modernsoapmaking.com/blog/the-most-popular-fatty-acid-profiles-in-soapmaking

@DeeAnna also has a good blog/ post on her website Classic Bells "What do the SoapCalc numbers REally mean? i found it really helpful when I started trying to increase hardness and longevity, and generally to come up with a well-rounded recipe. That link is:
https://classicbells.com/soap/soapCalcNumbers.asp

Ditto on what @AliOop said about lard. I have found it to be slow moving. So, increasing your lard will probably also give you a little more time to work on your design.

Good luck! Let us know if you come up with a harder, long lasting bar that has all the other properties you like!

Thanks!

 

[Zuleika]

I used to think I want my soaps to last long. But now having a bountiful stash of soap at home, I can't wait for them to melt away in the shower like a salt bar.

That said, I do have some stearic acid that I could throw into soap to see how it compares with my normal recipe.

 

[akseattle]

@Zuleika , you have a good point. I have so much soap I can't even test them all. So, I should be praying for soap melt-downs in the shower so that I can put new soaps in the shower.

I hadn't even thought about a soap's hardness or longevity until my younger son raised the concern.
He thought that he was using the soap incorrectly- like maybe it was only to be used on the face and not the whole body- because it melted away so fast.

I started wondering what other "giftees" were thinking about the soap I gave them. Then, as I read more about soap properties, I realized my soaps' longevity was not that high. I probably wouldn't care since, like you, I'm kind of antsy to bring in another bar. But, I'd rather not have my "giftees" scratching their heads, wondering why the soap is disappearing so fast.

If you DO end up trying out stearic acid, let us know what you think!!

Do you live in Singapore? I think my son might be going there in a few weeks (either that or he already came and went.) He started in Nepal, then went to Thailand and he is now in Vietnam. So, unless he had to fly through Singapore to go to Thailand, I think Singapore will be his next stop.

He bought some hand crafted soap in Nepal. One of its ingredients was chiuri butter, which I had never heard of until I saw it on the ingredients list. If it hadn't been so early in his journey, I would have asked him to bring some home for me- it's supposed to be equivalent to shea butter.

 

[Zuleika]

But, I'd rather not have my "giftees" scratching their heads, wondering why the soap is disappearing so fast.

True that! My normal recipe only has 25 longevity. I struggle a little with mushy soap so I may do a stearic test soon.

Do you live in Singapore? I think my son might be going there in a few weeks (either that or he already came and went.) He started in Nepal, then went to Thailand and he is now in Vietnam. So, unless he had to fly through Singapore to go to Thailand, I think Singapore will be his next stop.

Yes I do live in Singapore. Unless he's making a zigzag route, I think he hasn't landed here yet. I love Thailand!

One of its ingredients was chiuri butter

I went to read up on this. Sounds interesting! Probably really hard to get unless you're there.

 

[akseattle]

Sounds interesting! Probably really hard to get unless you're there.

Yes, I think Chiuri is very regional and grows at high altitudes.

 

[KiwiMoose]

@JillGat Try this:
Olive oil 15
Rice Bran oil 15
Castor oil 5
Coconut oil 20
Lard 35
Shea Butter 10

How does it come up in the calculator?

Actually not that great. I'm surprised at how low lard is in palmitic+stearic compared to butters. Why not try adding cocoa butter to the recipe (decrease the lard accordingly)? I use soy wax in mine and that does the trick.

Also try reducing your superfat to 2 or 3 percent.

 

[Quilter99755]

My go-to recipe has a longevity number of 38. I don't do anything fancy to my soaps because I'm lazy...or all the fancy stuff went out the window as I aged! LOL

Lard 50%
RBO 30%
Cocoa Butter 15%
Castor oil 5%

For my hubby and grandson the number is 33 and I know that this recipe takes quite a while to trace.

Lard 85%
Coconut oil 15%

By changing my lard to Walmart's GV Shortening with tallow and lard in some recipes, it can go over 40 for longevity. There was some reason I stopped using that...might be because I don't like to go into the local Walmart...but think it was a texture thing that I didn't like.

My triple rice soap has 31 longevity, but the same recipe with GV tallow/lard mix rises to 35.

Lard 40
RBO 30
Sweet Almond 20
Cocoa Butter 10

I don't use olive oil in any of my recipes as I found it made my skin itchy and that was after 10-12 months of a cure. I substituted RBO for the olive oil but sometimes will use Sweet Almond...it just depends on what I have in my cupboard. Since I am sending soap to my kids who live in Hawaii, I do want the longevity numbers at least in the 30's so I don't have to do that too often. Luckily, she has not had any problems with DOS in any of the soaps I have sent her.

 

[cmzaha]

Also lowering your CO will help since CO is a highly soluble oil. I very seldom go over 19% but balance out my cleansing percentage with my other oils to keep in in the range of 12%, which keeps my bars nice on the skin and long-lasting. I like 40/20% tallow/lard but I admit this does not give a long working time.

 

[KiwiMoose]

My go-to recipe has a longevity number of 38. I don't do anything fancy to my soaps because I'm lazy...or all the fancy stuff went out the window as I aged! LOL

 

[MelissaG]

Just a thought but if you just use the ends of the soap for your personal use, not a whole soap bar, then you can test the ends yourself, it will wear away faster, and you can sell the whole bar.