# Sat : Unsat ratio



## Cattleyabubbles (Feb 6, 2010)

How does the *Sat : Unsat ratio* affects the soap's qualities?


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## PrincessPeach (Feb 12, 2010)

--bump--

I'm curious about this, too.  Thank you.


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## rubyslippers (Feb 13, 2010)

I've tried to research this on the internet and the only thing I've found so far is waaaaaay too deep for me.  I need the 101 class.    Maybe someone that has some knowledge of this could explain it in simple layman's terms.


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## donniej (Feb 13, 2010)

This is just from my experimentation...

Saturated oils like lard, tallow and fully hydrogenated shortenings make for a very hard bar that cleans well but isn't very nice on the skin.  

Unsaturated oils like soy and olive oil are softer and don't last as long but are much "nicer" on the skin.  

For example, a bar of soap that's made entirely of high-stearic acid oils feels just like commercial soap (like Ivory, etc...).  
A bar made entirely from soy will clean good and is nice on the skin but gets soft easily and makes an "oily" lather.


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## rubyslippers (Feb 13, 2010)

Thanks donniej.....that's plain and simple and in language I can understand


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## IanT (Feb 13, 2010)

donniej=the man with the plan


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## RoseMarie (Feb 14, 2010)

May I ask a question about this? I hope you don't mind..... now if you add other oils that are good on the skin,  to these that are hard on the skin, that would make it better huh?


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## donniej (Feb 14, 2010)

Yes, RoseMarie.  It's exactly that balancing act that makes this the type of hobby full of trial and error.  And since everybody likes different properties, there is "one size fits all" recipe.


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## PrincessPeach (Feb 15, 2010)

Does the ratio affect the time it takes a batch to trace or harden?


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## donniej (Feb 15, 2010)

I've never timed it but it's my gut feeling that saturated oils trace faster than unsaturated oils at the same temp.  Pure soy for example seems to take a lot more heat (~150*F) where I'd work closer to 100*F for a saturated oil like 100% hydrogenated oils.  

Saturated oils may be harder after un-molding than unsaturated because they're harder oils, but this doesn't effect the 3 to 4 weeks drying time.  Both become much harder as the water evaporates.


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## IwantItgreen (Apr 24, 2010)

Does the ratio tell anything about how drying the soap is?  
For example, would 56:44 tell you if it is more moisturizing or more drying?


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## Happysoap (Jan 28, 2014)

I thought i would give this threat a bump ti see if we can get it going again. I am curios to hear an answer to this question


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## Tienne (Jan 28, 2014)

The higher the unsat number, the more conditioning the soap will be on  your skin and the more absorbable the oils are on your skin. Oleic,  linoleic and linolenic are the fatty acids that contribute to that, but  you don't want to go too high on the total of linolenic and linoleic  acids, as they are the ones that are prone to rancidity and DOS. Oleic  has a longer shelf and is less prone to DOS, but too much of that will  instead give your soap a slimy consistency. (Example: Castile soap.)

Keep  your total amount of linoleic plus linolenic at 15 or under and if you  go higher than 40 or 50 for your oleic, that's when your soap will start  to getting that snotty, slimy feel to it. See if you can find a good  balance between all those fatty acids.  If you _do_ have a lot of  linoleic and linolenic in your recipe, you should add ROE, unless the  oil you're using is high in vitamin E. (You could also just add in some  extra vitamin E.)

I add ROE to all my oils that have a lower  shelf life as a rule and if my recipe is particularly high in linoleic  and/or linolenic, I'll also on top of that add in some extra Vit E to my  batter just for luck. 

Oils like canola, corn, and ordinary  sunflower oil are oils that are prone to rancidity and DOS. They're  really great on the skin, but they will need that little bit of ROE  added to keep the shelf life of the soap in order. 

The iodine  number is also a measure of the amount of unsaturated bonds you have  from linoleic and linolenic acids and that's a number you want to keep  as low as you can. The higher the number, the shorter the shelf life.


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