Alkalinity & Dryness

[Dean]

I've been thinking about why my skin can't tolerate handmade soap but its fine with lye based commercial soap. After dropping the lauric+myristic to about nil and doing long cures, I'm thinking it must be something else. I noticed a leading brand of soap with CO as the first ingredient isn't drying for me and that it also includes citric acid. I'm wondering if citric acid is being added after saponification to reduce the alkalinity so the soap will be less drying. What are your thoughts? Does alkalinity have anything to do with drying effect? Can the the alkalinity of HP or liquid soap be reduced by adding citric acid after saponifying? Obviously this can't be done with CP because it would affect the saponification.

 

[DeeAnna]

Soap is a salt. It's an ionic molecule (as opposed to a covalent molecule) for those who remember some chemistry. That means a soap molecule wants to break apart rather easily. Because of this, soap does things that don't always seem to follow "common sense" from a human perspective. The idea that soap is soap and will stay soap for the ages is not correct.

A stronger acid, such as acetic (vinegar) or citric (citrus), is a bully. By comparison, fatty acids are 98-pound weaklings. Stronger acids always "get the girl" when talking about soap. They will react first with the sodium ions in the batter in your soap pot, or they will grab the sodium ions off the soap molecules even after saponification is long done. It doesn't matter.

Fatty acids get what's left after the stronger acid is satisfied. This is the reason why soap acts as an alkaline buffer. What this means is soap molecules will try to keep the pH more stable by giving up their sodium ions to stronger acid molecules and accepting hydrogen ions cast off from the stronger acid.

The consequence of this unequal competition is free fatty acids (aka more superfat) and the salt of the stronger acid (aka sodium citrate or sodium acetate.)

If the soap ingredients list is done with "what went into the soap pot" method, then the list will show citric acid. If done with "what came out of the soap pot" method, the list would show sodium citrate. They're both the same thing, but looking at it from different ends of the soap making process. I say "toe-may-toe" and you say "toh-mah-toe".

 

[Dean]

Thanks DeeAnna. So citric acid isn't an additive ingredient, its by product of the process?

 

[BrewerGeorge]

Beyond what DeeAnna says about the citric acid on the label being how they describe the chelator, there is also the fact that the commercial soap process is SO different that it can be sketchy trying to use it to draw conclusions about traditional processes like we use.

As for not tolerating handmade soap, what's your water like? How hard? Have you used chelators in your soaps that have performed poorly for you?

 

[BrewerGeorge]

Thanks DeaeAnna. So citric acid isn't an additive ingredient, its by product of the process?

Other way around....

Does the ingredients list say 'coconut oil' or does it say 'sodium cocoate?'

 

[Dean]

Other way around....

Does the ingredients list say 'coconut oil' or does it say 'sodium cocoate?'

Hi George.

Never used chelators.

Not sure if water is hard or soft. Its LA City water.

Ingredients:
"Organic Coconut Oil* Organic Palm Oil* Sodium Hydroxide** Water Organic Olive Oil* Organic Hemp Oil Organic Jojoba Oil Salt Citric Acid Tocopherol * CERTIFIED FAIR TRADE INGREDIENTS ** None remains after saponifying oils into soap and glycerin"

 

[BrewerGeorge]

Yep, that's the "before" ingredients method. So the citric acid is almost certainly the precursor to the sodium citrate chelator in the finished soap. Just as the coconut oil becomes sodium cocoate after the reaction is finished, so does the citric acid become sodium citrate.

A brief search about LA water says it's variable depending on where they get the water from. Odds are it's probably hard enough for a chelator to be beneficial. Read up here on sodium citrate or EDTA to buy and add to your soaps.

What you're attributing to intolerance for handmade soap could just be soap scum. I know that if I wash my hands in the garage sink (which doesn't hook to the water softener) my hands will feel much tighter/dryer than if I use the same soap inside with softened water. A chelator helps prevent soap scum.

 

[DeeAnna]

No, citric acid isn't a "byproduct of the process." The soap maker put it into the soap pot, just like everything else that went into the soap pot. If you put citric acid into the soap pot, you get sodium citrate out. If you put coconut oil into the soap pot, you get sodium cocoate out.

So look at the ingredients list you just posted. Citric acid and coconut oil are listed, not sodium citrate or sodium cocoate. Ergo they used the "what goes in the pot" method of writing the ingredients list.

If you're using city water, your water comes from the Colorado River and other surface water sources. Water from lakes, rivers, wells, springs invariably contains calcium and magnesium (aka the "hard water" minerals) to some degree. Even "soft" water contains some hard water minerals, just less than unsoftened water.

Our well water is slightly to moderately hard, and we use a home water softener. My skin feels tighter and drier, just like BG's, when the softener needs to be recharged to work at its best. The EDTA I use in my soap definitely makes a difference even with our softened water, but it's not a perfect solution. It's always nicer to bathe with soft water, even with a chelator in the soap.

 

[soapmaker]

I just used to use distilled water, which is cheap, at least here. I agree with DeeAnna, it's always nicer to bathe in soft water. I was itchy (really itchy) for years, with dry cracked skin until getting a water softener and using homemade soap!

 

[cmzaha]

Chances are in the City of LA your water is quite hard. I know Glendale, CA has very hard water. You can probably call DWP or whomever services your water to find out or goggle your exact city

 

[Obsidian]

Another thing to consider is the quantity of the types of oils you are using. I can't use high CO, OO or palm.

My soap needs to be at least 50% lard or it makes my skin dry and tight. High OO is the worse, Castile just destroys my skin. But weirdly a 100% coconut soap I can use as long as it has a 20% sf.

 

[soapmaker]

Another thing to consider is the quantity of the types of oils you are using. I can't use high CO, OO or palm.

My soap needs to be at least 50% lard or it makes my skin dry and tight. High OO is the worse, Castile just destroys my skin. But weirdly a 100% coconut soap I can use as long as it has a 20% sf.

We humans are strange! This reminds me of my aunt who gets sick on pork.....but sausage is O.K.

 

[cmzaha]

I just found out from my son in law whom works for DWP that LA City water is not very hard. He did not know the exact numbers but he said is is considerably softer than other cities in the area.