Genny's shampoo bar

[nframe]

Hello everybody,

I made yesterday a 500g batch of Genny's shampoo bar. I followed exactly her recipe as to the percentage of oils. The only difference is that I added 1 teasp. citric acid to the lye solution and 1 tablesp. babassu oil at trace. This morning the shampoo bar is still really soft - like soft butter. Is it going to harden? Is it the babassu oil that ruined it or the citric acid or both? I don't know what to do...

As usual, thank you to those who reply.
Nicole

 

[Paintguru]

I'm sure it will harden if you didn't screw anything up beyond your two mentions. Others have added citric before and 1T of babassu won't mess anything up (may have been good to include that in the lye calculation though if you didn't). That bar is soft in general, as IIRC, it has really no hard oils/butters in it. Mine have hardened significantly during cure, but still soften up quite a bit in the shower, even when well drained.

 

[houseofwool]

A 500 gram batch is pretty small to add additional oil and an acid which will neutralize some of the lye. I have no idea if it will harden up I would let it go for a bit and see what happens.

I had one batch that took nearly 6 months to harden. I have no idea why.


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[judymoody]

I think the citric acid would be the main issue - as mentioned, it will neutralize some of your lye, effectively upping your superfat and contributing to a softer bar.

 

[nframe]

Thank you for this. Should I make another batch (without any additives this time) and grate the soft shampoo bar into it? It would dilute the citric acid and babassu oil.

 

[FGOriold]

It is most likely the citric acid. I have been experimenting with it with my shampoo bar recipes adding it at trace and it definitely produces a softer bar that takes a bit longer to cure and harden up than the same formula without the citric acid.

 

[Robert]

Why are you adding citric acid, anyway?

 

[green soap]

This would produce sodium citrate. What does sodium citrate do for shampoo soap? or is a higher SF% the objective here? I am also confused about the citric acid.

 

[Obsidian]

I do believe thats its added to help lower PH so its gentler on the hair.

 

[judymoody]

It wouldn't lower the pH enough to make a difference. To get it close to neutral, the consistency of the soap would be very loose.

 

[DeeAnna]

But it ~won't~ lower the pH unless you add so much that the sodium salt (aka the soap) starts to break down, in which case you won't have soap anymore.

People seem to think pH is sort of like a bank account -- add a little acid and the pH will go down, add a little base and the pH will go up. Unfortunately, pH quite often doesn't work that way except in the very simplest of situations. This is especially true when you're talking about soap. <sigh>

 

[nframe]

Why are you adding citric acid, anyway?

Because I read that with citric acid you do not have to rinse with vinegar. I now see the error of my ways...
Thank you all.

 

[houseofwool]

But it ~won't~ lower the pH unless you add so much that the sodium salt (aka the soap) starts to break down, in which case you won't have soap anymore.

People seem to think pH is sort of like a bank account -- add a little acid and the pH will go down, add a little base and the pH will go up. Unfortunately, pH quite often doesn't work that way except in the very simplest of situations. This is especially true when you're talking about soap. <sigh>

DeeAnna, for the chemistry challenged among us (raises hand sheepishly) can expand upon this? I am not thinking of the ph of the final product in this way, but rather that there is a finite amount of base in the initial batter and adding citric acid will neutralize a portion of the base. However the amount of base neutralized may not be a one to one correspondence with the amount of acid added.


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[DeeAnna]

The pH of a fairly simple water-based solution -- for example a solution of vinegar in water or something like that -- is pretty much like a regular checking account. Money going out of a checking account drops the balance in the account and vice versa. If you add a little acid, the pH goes down in response. If you add a little base, the pH goes up in direct response. That's a pretty simple situation.

Many water-based solutions are more complicated. In essence, these solutions are more like a checking account with overdraft protection. With OD protection, the balance in the checking account is not the same as the total funds you can withdraw. If you draw out more than the checking account balance, the OD protection kicks to add more money. If you continue to draw money out of the checking account, then you will eventually run into trouble when the backup account becomes exhausted. But that might not be for a good long while.

Soap is more like a checking account with OD protection -- in chemical speak, you'd say the soap "buffers" the pH. The buffering ability of the soap helps the pH to remain roughly the same, even though we add more and more acid. It looks from our point of view as if "nothing's happening", but the soap is indeed gradually changing chemically as it continues to buffer the pH in response to more and more acid being added.

If we add enough acid, the buffering ability of the soap will finally break down. At that point, the checking account AND the OD protection are both exhausted. The pH will then go down in direct response to more acid ... and the soap will no longer be soap.

What makes soap ... soap ... is directly related to its alkaline pH and its ability to buffer its pH. Adding a little acid might seem as if it makes no difference. But the added acid does have an effect, although not in ways we humans can perceive, such as pH, physical appearance, etc.

Hope this helps!

 

[Robert]

Because I read that with citric acid you do not have to rinse with vinegar. I now see the error of my ways...

Like the time you put sugar in the soup so you wouldn't need it in the cake, right?