Longevity

[prissymissy]

What do I add to my batches in order to prolong the life of the soaps? No matter how I "plug-in" the ingredients, the longevity measurement hardly increases. I guess that I incorrectly assumed, that hardness of a bar lead to longevity. Thanks ahead of time

 

[Yooper]

It may not be what you add- it's the combination of ingredients. What I mean is, no matter what you add to an 80% olive oil soap, it just won't last that long in the shower compared to many other formulations.

The short answer is to add more 'hard' oils. That is, oils that are solid at room temperature. Think tallow, lard, palm oil, coconut oil, shea butter, etc. Now, too much coconut oil can be drying to the skin, so the recipe matters.

Make sure the soap is fully cured- and even the bars with lower longevity in the calculator will last longer.

"Hardness" means how hard the bar is after curing. For example.,100% olive oil bars will eventually get hard enough to pound nails. But, it won't last that long in the shower because it does sort of melt a bit and get slimy.

I have a recipe in the 'sample recipes', and it's a bar with tallow, and it lasts seemingly forever!

 

[prissymissy]

It may not be what you add- it's the combination of ingredients. What I mean is, no matter what you add to an 80% olive oil soap, it just won't last that long in the shower compared to many other formulations.

The short answer is to add more 'hard' oils. That is, oils that are solid at room temperature. Think tallow, lard, palm oil, coconut oil, shea butter, etc. Now, too much coconut oil can be drying to the skin, so the recipe matters.

Make sure the soap is fully cured- and even the bars with lower longevity in the calculator will last longer.

"Hardness" means how hard the bar is after curing. For example.,100% olive oil bars will eventually get hard enough to pound nails. But, it won't last that long in the shower because it does sort of melt a bit and get slimy.

I have a recipe in the 'sample recipes', and it's a bar with tallow, and it lasts seemingly forever!

Thank you so much for your in-depth explanation! I tall makes sense to me...I will try to incorporate more hard oils and increase curing time.

 

[Bubbles]

What do I add to my batches in order to prolong the life of the soaps? No matter how I "plug-in" the ingredients, the longevity measurement hardly increases. I guess that I incorrectly assumed, that hardness of a bar lead to longevity. Thanks ahead of time

All handmade soap has a limited longevity compared to commercial soaps. I don't worry about it. I just advise my customers to not allow their soap to sit in a puddle of water.

 

[bubblie]

What do I add to my batches in order to prolong the life of the soaps? No matter how I "plug-in" the ingredients, the longevity measurement hardly increases. I guess that I incorrectly assumed, that hardness of a bar lead to longevity. Thanks ahead of time

Sodium lactate might help as well. You add it to lye water before pouring it into your oils.

 

[prissymissy]

Sodium lactate might help as well. You add it to lye water before pouring it into your oils.

Thanks all!

 

[hanimsmaik]

Sweet almond oil and stearic acid

 

[ChemicalPyros]

The longevity (and hardness) of the soap is correlated with the quantity of the least soluble fatty acids.
Those fatty acids are mainly Palmitic acid and Stearic acid. I usually go for a ratio of 2:1 palmitic:stearic acid in the fatty acid profile of the soap. the more you increase those fatty acids in your soap the harder and more insoluble it will become.
this ratio stabilizes the foam and gives a nice usage time span.
you should note that too much of them in the recipe will destroy the foam. I would recommend that you go with around 20% palmitic acid and 10% stearic acid in the fatty acid profile for a maximum usage time span while still processable at room temperature.

 

[hanimsmaik]

Hi everyone, and thanks for sharing. In "Cold Process" the softness and the short life-span is most likely due to unsaponified fat and free glycerin mixed with soap.
thanks

 

[zlisik]

Isn't the longevity value a straight calculation of hardness-cleansing with this calculator? That's how I've read it described elsewhere as well.

Salt and sodium lactate don't effect the calculations in this calculator it seems. Nor do waxes. But all are commonly accepted as adding hardness. Perhaps they're too difficult to calculate?.

My feeling is that the calculated values are not absolute and more an estimate -- especially when you're adding ingredients that are not well documented or perhaps impossible to calculate accurately.

A castile soap is all over the graph but it's a well loved soap.. haha so maybe don't worry about it too much?

 

[ChemicalPyros]

The hardness, longevity and other characteristics in all online calculators (to the best of my knowledge) are overly simplified calculations. In my experience they are mostly adapted to multi-oil soaps. They become obsolete with single-oil soaps and specialty soaps. The reason behind this is that they use only one parameter for the estimates (the fatty acid content). Other parameters such as additives, curing time and temperature, whether cp, cpop, hp, superfatting, perfumes, ... are not taken into account with the calculators and since their effects are not fully understood to be implemented so it will come down to the soapmaker's experience. The more you make the more experienced you get and the better you understand the effects of all parameters.

In the mean time, this patent will explain why salts and organic salts improve the hardness and longevity of soaps.

https://patents.google.com/patent/US6218348B1/en

I know that my answer is ambiguous, but you have to take into account that when several parameters meet it is hard to understand the extent of the effect of each one on each property, only experimentation and serious notetaking will help you there.

 

[hanimsmaik]

The softness of soap is mainly because glycerin is not removed from it. To remove glycerin, it should be salted-out, and the rest of the fat is reacted afterwards.

 

[Yooper]

Yes, but remember that glycerine is great for your skin and makes the soap much better than store-bought detergent bars or soap where the glycerin is removed.

Glycerin is removed from commercial soap bars, and then sold as a skin conditioner!

 

[hanimsmaik]

Of course, this is very true. You see, a cold-process soap (which is excellent) will still have glycerin and unsaponified fat in it, and this is why it's good. On the other hand, if hardness (and long lasting) is favored, along with preventing (what some people may not favor such as the smell of the natural oil in cp soap and fast dissolving), then another way of making soap becomes required. The glycerin is returned to the soap (and it's super-fatted) after color and odor is removed. I hope this explains it?

 

[ChemicalPyros]

Glycerin for the first few percentages gives a softer and more soluble soap, but for percentages around 6% the soap actually hardens more and is less likely to dissolve (of course all percentages are for a final product after processing and curing). That being said, note that cold processed soaps contain automatically between 6% and 7% glycerin which is close to the optimal glycerin content.
As for the color and smell, personally I have never had a problem with those, but maybe in the case of oils that are not refined and deodorized, the final soaps may have some smell and color.

 

[Yooper]

I’ve noticed that my unscented soaps (which I prefer) don’t have an odor, except they do smell faintly of soap. Not the oil I made them with (like tallow), but a pure clean soap scent which I like.

With liquid soaps, I tend to scent them with essential oils before putting into the dispenser so I don’t notice much of a scent with them either.

 

[ChemicalPyros]

Once I tried to compare soaps made from refined and deodorized shea butter and unrefined or crude shea butter. The latter smelled like I was saponifying a dead rat and I was unable to continue working with it, while the refined shea butter soap smelled as you said "a pure clean soap scent".

For my personal use, I mix all the refined oils with crude olive oil, the final soap has a nice "olive" smell to it, maybe it is a cultural thing but I love this smell.

 

[Yooper]

Yes, I would guess that “saponified dead rat” wouldn’t be a popular fragrance.

I rarely use shea butter in soap these days, although I like that it makes such a hard soap. I’m using more deer tallow lately, and I really like it as well. For those who make only vegetable oil soaps, having a nice hard butter is a good thing in the mix so I would assume refined would be the way to go with it.

 

[Tony orourke]

The softness of soap is mainly because glycerin is not removed from it. To remove glycerin, it should be salted-out, and the rest of the fat is reacted afterwards.

hello sir. simple question I am making a hard shaving soap ingredients are castor oil, mango butter shea butter and kokum oil. I like it but wish it had more glide on my skin. do you have any pointers for me? also do I need to put in a preservative ?

 

[Yooper]

A lot of people like to use kaolin clay for more slip. No preservatives needed in soap .