How to use stearic acid in CP soap?

[topofmurrayhill]

4) If you plan on using lower flash point Essential/Fragrance oils, be ready to stir by hand like mad as your stick blender is going to be useless at lower temps if you have enough SA in your soap to cause the batter to seize due to insta-saponification when added.

The flash point of your fragrance is not at all relevant to the temperature you can soap at. The flash point is used by your supplier so they know how the fragrance can be shipped. It's of no practical use to a soapmaker or candlemaker.

 

[FNG]

The flash point of your fragrance is not at all relevant to the temperature you can soap at. The flash point is used by your supplier so they know how the fragrance can be shipped. It's of no practical use to a soapmaker or candlemaker.

If you soap at too high of a temp you risk evaporating those expensive oils. For example, when I make a high SA% shave soap I bring in the SA while it's still fluid at around 150-ish degrees. Let's say I want to add Bergamot EO (flash point @ 122F), I wait until the batter has cooled a bit before adding it to ensure the EO does not evaporate. At the very least I combine the SA with the other oils so I'm not dropping a 122F flash point EO on 150-ish oil. This makes the batter a bit harder to stir at this point.

It's a little extra elbow grease, but I think it's worth it to ensure I can get the most out of my low flash point EOs. Maybe you don't think this is necessary but I feel it helps after testing this out a few times.

EDIT: I guess I should also clarify that while the flash point denotes the point at which an EO becomes flammable, it is because it is evaporating and therefore easy to light with an open flame. It won't burn off when the soap saponifies and raises in temp as it should be already incorporated thoroughly at this point. However, if you drop a low FP EO on a hot bit of oil or soap batter some of it could evaporate off.

You can test this on your own and note you'll get a huge whiff of whatever you dropped in as it evaporates and permeates the air. Then mix a batch that is closer to the FP (I feel like 10-12 degrees is as far as I like to be off) and test the difference.

 

[topofmurrayhill]

If you soap at too high of a temp you risk evaporating those expensive oils. For example, when I make a high SA% shave soap I bring in the SA while it's still fluid at around 150-ish degrees. Let's say I want to add Bergamot EO (flash point @ 122F), I wait until the batter has cooled a bit before adding it to ensure the EO does not evaporate. At the very least I combine the SA with the other oils so I'm not dropping a 122F flash point EO on 150-ish oil. This makes the batter a bit harder to stir at this point.

It's a little extra elbow grease, but I think it's worth it to ensure I can get the most out of my low flash point EOs. Maybe you don't think this is necessary but I feel it helps after testing this out a few times.

EDIT: I guess I should also clarify that while the flash point denotes the point at which an EO becomes flammable, it is because it is evaporating and therefore easy to light with an open flame. It won't burn off when the soap saponifies and raises in temp as it should be already incorporated thoroughly at this point. However, if you drop a low FP EO on a hot bit of oil or soap batter some of it could evaporate off.

You can test this on your own and note you'll get a huge whiff of whatever you dropped in as it evaporates and permeates the air. Then mix a batch that is closer to the FP (I feel like 10-12 degrees is as far as I like to be off) and test the difference.

You can't infer anything useful from the flash point in the context of crafting. I've been hearing the same misconceptions for 10 years and witnessed many attempt to clarify it, but I'm sure the "burning off" idea will continue forever.

Flash point is a number that is derived from a standardized procedure to test flammability, but nothing special happens at that temperature except under the conditions of that test.

You are suggesting that flash point is directly related to vapor pressure -- the rate of evaporation -- but it is also related to how much vapor there needs to be for ignition to occur. Liquid A can evaporate more slowly than liquid B but have a lower flash point because it's simply more flammable and less vapor needs to be in the air above the surface.

Under the circumstances of soaping, evaporation is not significantly going to affect fragrance based on the volatility of one fragrance versus another -- especially when it's mixed into something else at 6% concentration. There's not enough evaporation to make a difference.

Temps are much higher in candlemaking, but people have not noticed any correlation with fragrance loss. Many of the same FOs are used, typical flash points are similar, and similar concentrations are used in wax as in oil. Candle mistakes are sometimes remelted to 180 F and poured again -- a torture test under which people have found that the fragrance is not significantly affected.

 

[FNG]

You can't infer anything useful from the flash point in the context of crafting. I've been hearing the same misconceptions for 10 years and witnessed many attempt to clarify it, but I'm sure the "burning off" idea will continue forever.

Flash point is a number that is derived from a standardized procedure to test flammability, but nothing special happens at that temperature except under the conditions of that test.

You are suggesting that flash point is directly related to vapor pressure -- the rate of evaporation -- but it is also related to how much vapor there needs to be for ignition to occur. Liquid A can evaporate more slowly than liquid B but have a lower flash point because it's simply more flammable and less vapor needs to be in the air above the surface.

Under the circumstances of soaping, evaporation is not significantly going to affect fragrance based on the volatility of one fragrance versus another -- especially when it's mixed into something else at 6% concentration. There's not enough evaporation to make a difference.

Temps are much higher in candlemaking, but people have not noticed any correlation with fragrance loss. Many of the same FOs are used, typical flash points are similar, and similar concentrations are used in wax as in oil. Candle mistakes are sometimes remelted to 180 F and poured again -- a torture test under which people have found that the fragrance is not significantly affected.

While we may agree to disagree, I think a more valid test of your candle example would be to see what happens when pure EO hits that 180F surface. Not while it's in a solution of candle wax already. As I mentioned, once it's in the soap and blended up it's not really a concern. The example you give doesn't seem to match what I've stated. Perhaps it is inconsequential if you're able to get it mixed in quickly enough, but this is difficult to do with SA in play. Remember, I didn't recommend this for any and all CP recipes :mrgreen:

I've personally tested this a few times to see the difference, particularly with SA since it has a higher melting point and I tend to work with 40-60% recipes for shaving frequently. Might be perception bias but I feel my methodology to correct this (whether necessary or not) is worth the possibility. To me the fact that it's vaporizing at all and significantly notable in the olfactory impact (sudden increase of EO scent) at higher temps pushes me to err on the side of caution.

 

[mikvahnrose]

Try make making this -

Palm 40%
Olive 35%
Coconut 20%
Castor 5%

Before you add the sodium hydroxide to the water, dissolve some sugar in to the water at a rate of 3% sugar compared to the oil weight. So if you are using 500g of oils in total, the sugar should be 5% of 500g.

This will boos the bubbles a great deal, but it will also make the soap hotter as it saponifies so if you usually insulate your soap you will need less - exactly how much will be some trial and error.

Susie is another bubble-lover and she uses lower coconut with no issues at all

That recipe does look pretty good, i would love to give it a go! But, I love shea butter soap, so what would be a good percentage of shea butter to use to replace some of the other oils, would this change the super fat percentage if at all? I just tested out my most recent soap after a week of cure time (not enough time i know) but i feel that it is too drying. The amount of bubbles that resulted was spot on though :]

 

[The Efficacious Gentleman]

That recipe does look pretty good, i would love to give it a go! But, I love shea butter soap, so what would be a good percentage of shea butter to use to replace some of the other oils, would this change the super fat percentage if at all? I just tested out my most recent soap after a week of cure time (not enough time i know) but i feel that it is too drying. The amount of bubbles that resulted was spot on though :]

Maybe take 10% from the palm for shea. Although I would also make it as is so that you can compare - many people can't tell the difference between 10% shea in a soap or that 10% being in lard. Palm is similar, but in a side-by-side comparison I am not too sure.

 

[kchaystack]

I agree with Effy, take 5 - 10% from your Palm and move it to shea. Remember too much shea can inhibit lather.

 

[mikvahnrose]

Yeah, that is exactly what i was thinking. Taking some away from the palm and using 8 percent shea.

 

[JeanmarieT]

I read you use 5% of stearic acid to your batch of soap.

Is that 5% ppo, or 5% of the entire recipe? (lye/oils/water?)

Is 5% even correct? Because i made a recipe with it (i think i used to much) and it traced up almost instantly.

I am very confused by this. I want my soap to be harder but i think im going about this the wrong way

All the guidelines I've read say to start with 0.5% or your oil weight, not 5%!!

 

[Relle]

All the guidelines I've read say to start with 0.5% or your oil weight, not 5%!!

This person hasn't been here for 3 yrs, so not likely to see your quoted post to them. This post is from 2016.

 

[JeanmarieT]

This person hasn't been here for 3 yrs, so not likely to see your quoted post to them. This post is from 2016.

Thanks for your concern.

 

[Lia chalid]

As others have mentioned, there are a multitude of other ways to get a harder bar aside from using SA. However, if you do choose to use SA in any amount, I have found it easier to work with in CP and HP settings by following a few recommendations:

1) Don't skimp on the water (or water replacement) in your lye solution as the extra fluidity helps you mix the SA in. You may need to cure longer or let the soap sit in the mold a bit longer depending on your oils and water % used overall.

2) Blend all of your other oils with the lye solution and add the SA last. It will still stiffen up immediately but I find it's easier to blend in this way, even with high SA% shaving soaps. It has a melting point of 156.7 degrees F so make sure you keep it around this temp before trying to add it.

3) Soap at a higher temp, as mentioned by and for reasons mentioned by others already.

4) If you plan on using lower flash point Essential/Fragrance oils, be ready to stir by hand like mad as your stick blender is going to be useless at lower temps if you have enough SA in your soap to cause the batter to seize due to insta-saponification when added.

I'm a newbie,
How I can add the SA on the last part? I melt the SA first or just add it powdery like that?

I've just add the SA powder at the oils and it couldn't mix and make the soap have so many white dots.

I really want to make a hard bar but I want it to be moisture enough to skin...
Can you tell me how to make it??

 

[earlene]

When I used stearic acid, I melted it with the soft oils, just like I do for any other hard oil. The melting point of stearic acid is 69.3°C (156.7°F). The heat transfer method won't melt it, so it has to pre-melted, and I find that some hard oils (including Stearic Acid) melt more uniformly with the surrounding warmer liquid oils to maintain the heat all around the surface of the harder oils as they float within the mixture.

 

[Gingerbread2]

That would be 5% of the total amount of oils. For example:

Lard 60%
Olive Oil 15%
Coconut Oil 15%
Castor Oil 5%
Stearic Acid 5%

Now, having said that, just because you CAN use it in a recipe, that does not mean you SHOULD use it in a recipe.

I have never used it, so I have no opinions about it. I was just answering the question.

I am using 5% of my oils as stearic acid in one of my basic recipes but I used the soap calc to calculate the results. I have being doing it for a few months and I am not having trouble with acceleration any more than I would with other some FO etc. I do find it really important to melt that stearic acid really well with other hard oils blending very well while it is hot and then add the other oils while they are hot. THEN I let my oils cool. It does start to thicken quickly but using the stick blender I just keep it moving long enough to make sure it is a very evenly mix. I have time to blend colours and make design but I don't waste time either. So far I am happy with the results.