baking soda

[sososo]

What if i use baking soda (sodium bicarbonate) in soap? What would be the bennefits of this? How much? How to use this - in water? in oils?

 

[Mighty Mama]

I've been wondering the very same thing. Wanting to make a laundry soap bar and was considering adding baking soda to the recipe. Apparently bicarb is an exfoliant when added to soap but what if you dissolve it and add it to the lye water?

 

[seven]

this post by soapqueen might interest you: baking soda soap

apparently, baking soda in cp does funky stuff..

 

[CanaDawn]

It definitely doesn't appear to work well in CP, and I guess I'm not sure why go to the hassle of a rebatch to add baking soda for laundry, rather than just mix baking soda into your powdered soap.

a quick google for the chemistry involved and we find: NaHCO3+NaOH <---> Na2CO3 +H2O or in peoplespeak: Sodium bicarb (baking soda) plus Lye reacts to form sodium carbonate (washing soda) and water (not ideal for making soap)

 

[Genny]

I've done it & many other soapers have done it and it works just fine. I used baking soda equal to my soap oils. I added it at light trace. Make sure you sift your baking soda first so there's no lumps. It makes the soap very hard, like a salt bar. It also is kind of exfoliating.

 

[CanaDawn]

That actually makes sense, I think. At trace there would be some saponification already, and so I would think some of the lye wouldn't be available to react with the bicarb - the soap might end up with a oil discount vs one without the baking soda in it, but the baking soda acts as a buffer, and the free lye could be converted to washing soda, with some baking soda remaining unconverted. I'm guessing here, though. Anyone want to add/correct this? (Buffers are kinda weird chemistry)

 

[sososo]

I've done it & many other soapers have done it and it works just fine. I used baking soda equal to my soap oils. I added it at light trace. Make sure you sift your baking soda first so there's no lumps. It makes the soap very hard, like a salt bar. It also is kind of exfoliating.

Baking soda equal to oils? Isn't it too much?
And what is the difference between such a baking soda bar and a salt bar?

That actually makes sense, I think. At trace there would be some saponification already, and so I would think some of the lye wouldn't be available to react with the bicarb - the soap might end up with a oil discount vs one without the baking soda in it, but the baking soda acts as a buffer, and the free lye could be converted to washing soda, with some baking soda remaining unconverted. I'm guessing here, though. Anyone want to add/correct this? (Buffers are kinda weird chemistry)

It would be good to know how much lye can "eat" 1 gram of baking soda...

 

[seven]

I've done it & many other soapers have done it and it works just fine. I used baking soda equal to my soap oils. I added it at light trace. Make sure you sift your baking soda first so there's no lumps. It makes the soap very hard, like a salt bar. It also is kind of exfoliating.

very interesting. looks like an experiment is coming up

 

[CanaDawn]

It would be good to know how much lye can "eat" 1 gram of baking soda...

Yes, it would..... but as I understand the chemistry, although the reaction is one molecule to one molecule (not gram to gram) it is a reversible one, and the baking soda acts as a buffer, which makes things a little more tricky.

NaHCO3+NaOH <---> Na2CO3 +H2O

the weight of 1 mol NaHCO3 (baking soda) is 84.007g
the weight of 1 mol NaOH is 39.997g

 

[sososo]

Yes, it would..... but as I understand the chemistry, although the reaction is one molecule to one molecule (not gram to gram) it is a reversible one, and the baking soda acts as a buffer, which makes things a little more tricky.

NaHCO3+NaOH <---> Na2CO3 +H2O

the weight of 1 mol NaHCO3 (baking soda) is 84.007g
the weight of 1 mol NaOH is 39.997g

So, can we say that baking soda has a "SAP" (I put it in quotes...) of 39.997 / 84.007 = 0.476 ? Much more than any oil.

 

[CanaDawn]

So, can we say that baking soda has a "SAP" (I put it in quotes...) of 39.997 / 84.007 = 0.476 ? Much more than any oil.

Well....I wouldn't say that. I'm not sure how to relate the chemistry to the soap.

One molecule of baking soda reacts with one molecule of lye to form one molecule of washing soda and one molecule of water.

I seem to recall a discussion about washing soda as a possible weak saponifier, but again, I don't know how to relate it all to the relation between baking soda and lye.

 

[ourwolfden]

Could you add it toward the end when making HP soap?

 

[Kansas Farm Girl]

I did add some BS to CP soap once, I don't have my notes with me at the moment, but for me it was too harsh on my skin. I am sure others would not have the same problem, but for me I didn't like the results.

 

[Ellacho]

I made the baking soda laundry soap in the past. Since it did not mix well at trace, I added it with warm oils. It came out really well. Once it's cured, I used the food processor to grind it into a powder form.

 

[eucalypta]

I made it and like it.

I first heard of baking soda soap on "the Dish".
Learned there that "baking soda soap" a.o. is used like a deodorant soap, especially in summer.

It has been on the commercial market in the US for more than a century.
Grandpa's Baking Soda Soap

Ingredients :

Sodium Palmate, Sodium Cocoate (OR) Sodium Palm Kernelate, Water, Glycerin, Sodium Bicarbonate, Ethylhexyl Hydroxystearate, Sodium Chloride, Sodium Gluconate, Pumice, Titatnium Dioxide.

 

[sososo]

I made it and like it.

I first heard of baking soda soap on "the Dish".
Learned there that "baking soda soap" a.o. is used like a deodorant soap, especially in summer.

It has been on the commercial market in the US for more than a century.
Grandpa's Baking Soda Soap

Ingredients :

Could you tell us how much bakingsoda you use and where you put it - in oils,in water or in trace?
thank you.

 

[seven]

baking soda soap

from the looks of it, i think it didn't go very well. the soaper didn't tell when and how she mix the BS though. perhaps mixing it with the oils before lye is the best way to go, as per Ellacho's post?

 

[eucalypta]

@sososo

Could you tell us how much bakingsoda you use and where you put it - in oils,in water or in trace?
thank you.

2-3 tbsp/ppo

I like to mix the baking soda in with the oils, for easier soaping; but at trace it worked fine too (with a small test batch that was).

he soap works a bit like an exfoliant, but is not harsh at all.

 

[sososo]

Thank you, Eucalypta. I will try.