Adding Citrus Juice to CP Soap?

[JuliaGulia]

Good luck! Isn't it nice to have your own supplies right in your back yard?

It is!! I don't think I could live with out having a garden!

 

[Kansas Farm Girl]

Hopefully this summer I can get one planted that will not burn up in the heat, with the drought we have no one I know has had a decent garden in the last few summers. Doesn't matter how much water you pour on it, the plants don't seem to like 100+ degree weather with 5% humidity for as long as we get it. Somethings don't care, though, like the mints.

 

[shawnynicole]

Cruised through my old soaping files (1999-2003 when I quit soaping), and found the following conversation about lemons in soap. There's an interesting tidbit on using lemon as a chelator for hard water and for preventing soap scum.

I really should try lemon juice, or at least citric acid, as I have very hard water and haven't been able to find any EDTA.

I did not check the above recipe. I really should spend more time reading my own files... I bet I have answers for nearly every question. LOL

Yes! Using lemon juice makes a great bar of soap and works as a water softener.
I used about 0.5 oz lemon juice per pound in my 100% coconut oil laundry and dish soap @ 0% superfat. Use your recipe as usual, maybe even discount the water a bit, then add the lemon juice at trace so that most everything is saponified. The results were beyond amazing! We have terribly hard water here and this soap works wonders, even helps whiten whites. It even somehow made the soap more gentle so as to washing my dishes with the soap (and inevitably my hands) made me leap and try it on my body. I've tried Kirk's 100% coconut oil and wouldn't dare try using it again on my body. But when I used mine with the lemon juice, I was shocked that I could actually use it and that it left my skin soft. It's not something I would do on a regular basis because although soft, coconut oil soap still dries the skin a bit, but it was nonetheless usable. I've made soaps with 25% coconut oil/75% olive that were still harsh for me. I plan on using those same recipes with lemon juice to see if that changes everything.

 

[DeeAnna]

"...add the lemon juice at trace so that most everything is saponified..."

I regret to say that adding ingredients at trace to prevent them from being saponified is a bit of an old soaper's tale. "Trace" means just enough soap has formed to keep the oil and water phases in emulsion, and nothing more. Saponification is still in full swing at trace and there is still a lot of unreacted lye in the batter, so ingredients added at trace will still react quite well with the lye.

"...It even somehow made the soap more gentle..."

That is in large part because the citric acid (lemon juice) added at trace increased your superfat, because the acid reacted with the lye to form sodium citrate. Not to say that the sodium citrate isn't useful, but the lye consumed by this reaction cannot react with your fats. NaOH reacts with acids much quicker and easier than it reacts with the oils.

If you want an acid to not react with the lye, do a hot process soap and add the acid after saponification is complete. YMMV and all that, but it's hard to argue with lye.

 

[MOGal70]

So what I don't understand is.... Coffee is very acidic and so is lemon juice. So why can you make a soap with strong coffee, but might have issues with lemon juice?

 

[dagmar88]

The PH of lemon juice is around 2, coffee around 5.

 

[Lindy]

Lower your superfat to accomodate the low pH

 

[Robert]

I'm not exactly sure how Lush can add fresh citrus juice to CP soap. I would imagine the acidity in the juice would neutralize the lye and it wouldn't ever set up.

Simple: just use more lye to compensate.

And I also here a list of the quantitative ingredients straight from the Lush site :
Water (Aqua) , Rapeseed Oil , Coconut Oil (Brassica napus; Helianthus annuus; Cocos nucifera) , Propylene Glycol , Cornstarch (Zea mays) , Lemon Peel (Citrus limonum) , Orange Peel (Citrus dulcis) , Sodium Stearate , Sodium Hydroxide , Sodium Lauryl Sulfate , Fresh Organic Lemon Juice (Citrus limonum) , Fresh Organic Orange Juice (Citrus Aurantium dulcis) , Lime Oil (Citrus aurantifolia) , Fragrance , Lime Peel (Citrus aurantifolia) , Grapefruit Oil (Citrus grandis) , Fresh Organic Lime Juice (Citrus aurantifolia) , Lemon Oil (Citrus limonum) , Glycerine , Sodium Chloride , EDTA , Tetrasodium Editronate , *Citral , *Geraniol , *Citronellol , *Limonene , *Linalool
And if Lush doesn’t use the CP method to make this soap, I am completely sorry about this incorrect post!!

From that list, we can be fairly confident they're not using a kettle process. They would not be likely to buy sodium stearate rather than stearic acid, as long as they're adding NaOH. That large a quantity of propylene glycol (3rd ingredient) makes me think saponif'n is done separately, not that it wouldn't survive, but because it looks like the sort of processing aid you'd use if you were using it not as a catalyst but in a melt & pour.

 

[tryanything]

Yes! Using lemon juice makes a great bar of soap and works as a water softener.
I used about 0.5 oz lemon juice per pound in my 100% coconut oil laundry and dish soap @ 0% superfat. Use your recipe as usual, maybe even discount the water a bit, then add the lemon juice at trace so that most everything is saponified. The results were beyond amazing! We have terribly hard water here and this soap works wonders, even helps whiten whites. It even somehow made the soap more gentle so as to washing my dishes with the soap (and inevitably my hands) made me leap and try it on my body. I've tried Kirk's 100% coconut oil and wouldn't dare try using it again on my body. But when I used mine with the lemon juice, I was shocked that I could actually use it and that it left my skin soft. It's not something I would do on a regular basis because although soft, coconut oil soap still dries the skin a bit, but it was nonetheless usable. I've made soaps with 25% coconut oil/75% olive that were still harsh for me. I plan on using those same recipes with lemon juice to see if that changes everything.

NOW I read this! I just made my first 100% coconut oil laundry soap a few days ago. I'll have to try this next time!:-D

 

[DeeAnna]

Lemon juice, according to one report, has 1.44 grams of citric acid per fluid ounce.

"...The chlorogenic acid content of a 200 ml (7-oz) cup of coffee has been reported to range from 70-350 mg...." That translates to a maximum acid amount of 0.5 g chlorogenic acid per fluid ounce of coffee.

That's just a quick check of the information on the internet, so I could be off, but Dagmar's info also correlates with the info I found. The point being the amount of acid in lemon juice is on the order of 3 to 8 times more than the acid in coffee.

 

[shawnynicole]

"...add the lemon juice at trace so that most everything is saponified..."

I regret to say that adding ingredients at trace to prevent them from being saponified is a bit of an old soaper's tale. "Trace" means just enough soap has formed to keep the oil and water phases in emulsion, and nothing more. Saponification is still in full swing at trace and there is still a lot of unreacted lye in the batter, so ingredients added at trace will still react quite well with the lye.

"...It even somehow made the soap more gentle..."

That is in large part because the citric acid (lemon juice) added at trace increased your superfat, because the acid reacted with the lye to form sodium citrate. Not to say that the sodium citrate isn't useful, but the lye consumed by this reaction cannot react with your fats. NaOH reacts with acids much quicker and easier than it reacts with the oils.

If you want an acid to not react with the lye, do a hot process soap and add the acid after saponification is complete. YMMV and all that, but it's hard to argue with lye.

Superfatting has never made a soap more gentle, in my experience, like I hear soapers say. A superfatted harsh soap is a harsh soap with extra oil. If I were to theory why the lemon juice made the soap more gentle, it would be that it balanced the pH. I do believe that some of it may have reacted with the lye to create sodium citrate as that would explain the water softening properties. However, adding at trace vs using it in replace of water in the beginning clearly proves that most saponification has taken place. The amount of lemon juice added at trace is not significant as to drastically affect any oils that have not reacted with the lye and the amount of oils left un saponified at this stage depends on how well into trace the soaper is when the lemon juice is added. Also, I'd have to say despite what soapers say about saponification taking anywhere from 72 hours - 4 weeks just does not match what science tells us. I have a bit of a chemistry background and I'd have to say that the author of Smart Soapmaking, Anne L. Watson said it quite well when she explains that the increase in temp from the time your pour the lye into the oils till everything is emulsified is what will clarify that the chemical change (saponification) has taken place. In short, in chemistry, exerted heat is sign a chemical reaction has taken place. Please excuse the vagueness of my chemical reaction explanation.

 

[Robert]

Also, I'd have to say despite what soapers say about saponification taking anywhere from 72 hours - 4 weeks just does not match what science tells us. I have a bit of a chemistry background and I'd have to say that the author of Smart Soapmaking, Anne L. Watson said it quite well when she explains that the increase in temp from the time your pour the lye into the oils till everything is emulsified is what will clarify that the chemical change (saponification) has taken place. In short, in chemistry, exerted heat is sign a chemical reaction has taken place.

It's a sign that some chemical rxn has taken place, not that rxns have completed.

Suppose you turn on the furnace in a bldg. with no thermostat. The temperature will increase, but the fire will still be on even when the temperature in the bldg. hits its maximum. Heat is being generated, but heat is also leaving the bldg. The fire just keeps up the temperature once you get to a steady state where the furnace is heating the bldg. as fast as the heat escapes.

Similarly, the temperature in your rxn vessel (soap kettle) gets to a steady state while saponif'n is still going on. In fact the temperature will eventually drop while saponif'n is still going on, when the rate of the rxn slows down.

If you saponified a very small amount of material in a tiny reactor, say one with a water jacket, then you could pretty much pinpoint by a thermometer the reaction rate by the heat it was generating, because the heat would leave so quickly. But in a practical sized pot, that won't be the case.

A rxn like saponif'n with an approximately stoichiometric amount of lye making solid soap is going to come close to 2nd order kinetics, with lye + water being like one reactant and fats the other. Even though there's an excess of water (because water becomes part of your finished soap), as the mass solidifies there's less material available to react, so the rxn slows down. It's a good while before it finally shuts off for practical purposes.

 

[KJW2601]

Would you say then 2 oz of lemon juice ppo would be safe to use to prevent spoiling the whole batch?


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