# HP lard soap stays caustic. What did I do wrong ?



## Gaspar Navarrete (Mar 5, 2014)

Hi everyone,

Help! I tried to make a hot process soap out of bacon grease saved from frying bacon in the kitchen, but the finished lard soap stays caustic. Below is what I did. Could someone tell me what I did wrong ?[/B]I had 41.4 oz of bacon grease, (left from frying bacon). I cleaned it by rinsing it with very hot water a few times.

The lye I used was Roebic Crystal Drain Opener. This link describes this product: http://www.roebic.com/heavy-duty-crystal-drain-opener.shtml It's says "100% sodium hydroxide" on the bottle.

Here was my lye calculation:
(41.4oz) x (0.138 ) = (5.7132 oz lye) ... with no discount
(5.7132) x (0.96) = 5.4846 ... with a 4% discount

To double check my value, I used the lye calculator at thesage. It gave me the following: 10-16oz of water, 5.51 oz of lye (at 4% excess fat), for 41.4 oz of lard. I also used the lye calculator at brambleberry. It gave me the following: 13.66 oz of water, 5.485 oz of lye (at 4% excess fat), for 41.4 oz of lard.

So I used 5.5 oz of lye with 16 oz of distilled water.

Combining and cooking: I mixed the lye solution with the melted lard (not at the same temp) and mixed it with a powerful stick blender (mixing bit attached to an electric drill). After there was a light trace, I started to cook it in a crock pot in the low setting. The edges started to gel and the gelled areas started to expand toward the center of the mixture. Even after 4 hours of slow cooking, the phenolphtalein was still quite red (ie caustic). I thought it is supposed to get less alkaline the more you cook it. I ended up throwing vinegar into it and throwing the batch out.

Your input and advice would be quite helpful.


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## Obsidian (Mar 5, 2014)

You should have done a zap test with your tongue, phenolphtalein will show red when the PH is above 10(I think) which is exceptable for soap and doesn't mean its still caustic. Soap is naturally high in PH, I bet your soap was just fine.


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## DeeAnna (Mar 5, 2014)

"...Even after 4 hours of slow cooking, the phenolphtalein was still red (ie caustic)...."

Overall your recipe and method looks reasonable, so lets move on to why you think the soap was lye heavy. What source of information did you use as a guide when trying to test your soap with phenolphthalein in this manner? It's something I see people doing, but it makes no sense to use phenolphthalein in this way. I think it leads to false positives -- in other words, your soap may well have been perfectly fine.

In a dilute solution, phenolphthalein (aka PhPh or phenol-p) is colorless below about 8.2, turns pink about 8.2, turns bright fuschia about 10, and above 12 will flush fuschia at first, then fade to colorless. A lard soap is made of mostly palmitic and oleic acids and the natural pH range of soap with these fatty acids is roughly 9 to 11. So, yeah, PhPh could easily indicate the pH is "high" for a lard soap. But it's not necessarily an _unsafe_ pH -- it may well be a perfectly normal pH for the type of soap you're making.

If you're going to rely on PhPh as an indicator, then test the soap solution as a chemist would properly do it. From summerbeemeadow.com:

"...The proper way to use phenolphthalein is to dissolve some liquid or solid soap in a roughly 50:50 mix of distilled water and alcohol (ethyl or isopropyl rubbing alcohol is ok) in a clear glass. When the solution is as clear as it will get, add a drop or two of phenolphthalein solution and stir it. Then view it well-lit in front of a white background. This way, one can see the slightest little bit of pink color (which is ok) and all its graduations up to a deep red (definitely not ok)...."

But regardless of how you choose to test your soap, just be consistent with your method and practice often so you are quite familiar with how your chosen test works. Only with consistency and experience can you judge whether the results indicate a skin safe soap or not. If you don't have the experience to make that judgement and don't have an experienced soaper to help you, then back up your test method with a secondary test -- and I recommend the "zap" test.

Dampen your fingertip and gently rub it over the surface of the soap. Lightly touch your fingertip to your tongue. If the soap is excessively alkaline -- not skin safe -- the sensation you will get will be like a static shock or a "zap" from a battery. The sensation is sharp, unmistakable, and immediate. If you get a salty, metallic, or bitter taste ... that is not a zap. If you wonder if you got a zap ... it's not a zap. If you get a bland or "soapy" taste ... it's not a zap. If you do get zapped, rinse your mouth with fresh water. If you didn't get zapped, feel free to lick your soap to your heart's content (or not)!


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## Susie (Mar 6, 2014)

I have used the Roebic Lye for every batch I have made thus far.  And I have had no problems with it.  Good air tight bottle and performs well.  

I zap test my soaps.  I am still waiting for my pH meter.  Apparently it got back ordered.  I will probably continue to zap test my bar soaps even after I get it.  It is, to my mind, the definitive safe/not safe test.


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## seven (Mar 6, 2014)

That's a shame that you threw it out, even if it was caustic (which i dont think it was), you can still save it.

I agree with DeeAnna, i prefer to rely on my tongue to test.


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## dixiedragon (Mar 6, 2014)

From what you describe, I don't think your soap was caustic. I would suggest you try it again, pour the soap, and after a week or so, try washing your hands with it. It will not be totally cured at a week, but it will be safe enough for hand washing.

What kind of scale did you use? Was it a scale that measures in decimals, and could accurately measure 5.5 oz?

Is there a reason that you chose the 4% superfat? The "standard" superfat (using the term loosely!) is between 5% and 6%. Some soapers use higher, but not many go lower than that, unless they have a specific purpose in mind.


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## MzMolly65 (Mar 6, 2014)

Gaspar I'm new to soap so I can't comment on your recipe or this experience but I have to say I'm impressed that someone made soap with bacon grease.


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## shunt2011 (Mar 6, 2014)

I agree with the advice given already.  I also only rely on the zap test.  I've heard many say that PH strips and meters are not accurate for CP/HP soaps.


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## songwind (Mar 6, 2014)

Is it possible that the bacon fat was more than 4% "other stuff?" Bacon fat out of the pan isn't pure lard - and the description you used of cleaning it sounds like it's probably less thorough than the multi-step process generally used to turn animal fat into tallow/lard.


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## Gaspar Navarrete (Mar 6, 2014)

Thanks everyone for your prompt replies:

To everyone:

The reason why I was looking for clear phenolphtalein is in this video.
Go to (6:18 ) in this video to hear about Phenolphtalein use from "Suds & Buds": [ame]http://www.youtube.com/watch?v=Yg6tEa9hGFE[/ame]
The video seemed reasonable to me so I went by it. Perhaps there was a mistake; I'm new to all this.

Several soapmakers were very retiscent about doing the zap test. That's what discouraged me away from it. But I suppose it can be done if it passes the solution test that DeeAnna described. If one does the zap test regularly, over the course of time, don't you begin to ingest appreciable amounts of NaOH ?

I learned quite a bit from your replies. I wasn't expecting people to say that my process seemed ok.

To DeeAnna:

Okay I will try the water & alcohol solution test. I was just putting a drop of phenolphtalein on a sample of soap batter, and that drop was turning bright red.


To Obsidian:

The phenolphtalein person told me that phenolphtalein changes to pink above a ph of 9. Is it possible that there are different kinds of Phenolphtalein ? The Phenolpthalein that I have is used in high school chemistry classes and I believe is a powder diluted in an alcohol solution.

To Susie:

You mentioned a PH meter. I never heard of these. What is that ? How does it test the ph ? How reliable is it ? What are the price ranges ? Is there a website that talks about this ?

To dixiedragon:

The scale I used was a Pelouze SP5 scale. 5lb capacity. Measure to tenths of an ounce or in grams. Here's a link describing the scale:
http://www.amazon.com/dp/B00006IACE/?tag=skimlinks_replacement-20

I chose 4% lye discount because I was wondering whether or not my soap would become too oily with unreacted fat at higher %s. I don't want to put fats & oils on my skin. Is it too low ?

To MsMolly65:

Thanks. There is someone in our household that likes bacon. I thought it would be a shame to waste the bacon grease.

To songwind:

I was wondering exactly the same thing ! When one cooks bacon, one naturally uses alot of heat. Could the heat have partially broken down the lard into other sustances that do not react with lye ? If there was a significant amount of these other substances in my lard, that I might have been actually taking a sizble lard discount, which would have resulted in unreacted lye. I will search for a discussion on this.


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## new12soap (Mar 6, 2014)

Since this topic has come up again... 

http://millersoap.com/phtome.html

http://jenorasoaps.blogspot.com/2013/05/ph-handmade-cold-process-soap-and.html

Because of the high pH of soap, phenolphthalein is of no real use, and it is nearly impossible to determine the exact pH. Because of the surfactant nature of soap, pH strips really don't work. And because soap is really only in suspension, not in solution, only a very good pH meter kept properly calibrated is of any real use. None of which tells you what you want to know since a perfectly good soap will always be alkaline!


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## Gaspar Navarrete (Mar 6, 2014)

If I understood your millersoap.com article correctly, there is one valuable thing (I think) that phenolphtalein can show.

If, and only if, it is clear then one can safely say the pH is below 10.  Since it begins to turn red between 8.2-9.0.

If the phenolphtalein is pink or red, then it becomes useless since you now cannot accurately determine the pH.


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## Lin (Mar 7, 2014)

At a dangerously high pH though the pheno-p will flash bright fuscia and then turn clear, so if that was missed it could be very bad.


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## DeeAnna (Mar 7, 2014)

"...If I understood your millersoap.com article correctly, there is one valuable thing (I think) that phenolphtalein can show...."

Um, the Millersoap article doesn't mention phenolphthalein once, so I gather you mean the Jenora article. 

Honestly, looking at her numbers, the conclusion I drew is phenolphthalein is remarkably inconsistent and under-reports pH in this type of testing environment. Some quotes that show this inconsistency:

"Phenol looks around 8.5? Both pH strips look around 8 and digital pH reading is 9.69.
For the phenol (Phenolphthalein) test, from the pink, we can see they are over 8, but don't look over 10. ...With the digital ph metre, they both tested slightly over 10.
"Phenol makes the pH look quite low, the orange one around 8 or 8.5 and the lemon sea salt soap looks below 8! ...Then the pH [meter] tests the lemon sea salt soap in at 9.78! and the orange poppyseed soapover 10...
"Phenol looks around 8.5? Both pH strips look around 8 anddigital pH reading is 9.69.
"phenol, it looks like the pH is lower than 8, the paper strips look around 7 and the digital meter reading is 9.29

"...If, and only if, it is clear then one can safely say the pH is below 10. Since it begins to turn red between 8.2-9.0...."

If phenolphthalein is clear, the pH of a dilute solution is below 8.2. If it's fuschia then slowly fades to clear, the pH is above 12. If it's anywhere from pink to fuschia, the pH is between 8.2 and 12, with greater intensity of color correlating roughly to higher pH. And this should be done in a room temperature dilute solution of soap, water, and alcohol for best results -- not dropped on a paper towel wetted with soap solution, not dropped on a solid soap, and not dropped on a hot dab of HP batter.

PS: My huge thank you to New12soap for the links -- much appreciated!


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## Kansas Farm Girl (Mar 7, 2014)

Gaspar said:


> If one does the zap test regularly, over the course of time, don't you begin to ingest appreciable amounts of NaOH ?



Actually you are not ingesting the NaOH. 1) it has been saponofied and is no longer lye. 2) you are not swallowing the soap but will wash your mouth out typically and 3) you actually use lye in cooking.
http://sodium-hydroxide.com/caustic-preservative-crispy-food-all-you-need-to-know-about-lye-water/
4) see the thread on tooth soap, using soap rather than toothpaste

I know the first time I heard about the zap test I did not want to do it but I finally did and other than a nasty taste it wasn't HORRIBLE. Then I did get a zap. WOW! but it was over quick and I knew what I needed to do to save my soap. I never have to worry about running out of a chemical, or wonder if I read it wrong, I know instantly. It's no worse than giving you honey a quick kiss and static electricity zaps your lips. In fact that may be worse.


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## The Efficacious Gentleman (Mar 11, 2014)

I zap test, mainly because I don't need anything that I don't already have for it!  But also because you cannot tell from the pH if a soap is safe or not.  Is 9 safe but 10 not?   Or is 11 not safe?  Actually, it's safe when all of the lye has turned to soap (saponified).  It's unsafe when there is lye that has not saponified.  You can't 100% tell that using the pH, so zap test is what I go on.


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## lady-of-4 (Mar 31, 2014)

The Efficacious Gentleman said:


> I zap test, mainly because I don't need anything that I don't already have for it!  But also because you cannot tell from the pH if a soap is safe or not.  Is 9 safe but 10 not?   Or is 11 not safe?  Actually, it's safe when all of the lye has turned to soap (saponified).  It's unsafe when there is lye that has not saponified.  You can't 100% tell that using the pH, so zap test is what I go on.



Actually,  ph 10 or above is NOT considered skin safe. Molecular breakdown is occurring, whether you're skin feels it or not. High ph and lye excess/heaviness are synonymous. The more soap is saponified/neutralized, the lower the ph will go until it hits its lowest point without breaking the soap back down. Over neutralization, where more lye is taken away, Wil cause breakdown. That begins at around a ph of 8-8.5.

For example mixing lye water, I'll use NaOH,  with citric acid water will cancel each other out, thus neutralizing. 0.571oz of lye for an ounce of acid in 4 ounces of water each. Now in a 3rd cup, put equal parts of the 2 solutions. Right there you will have sodium citrate, and is neutralized. Now add more lye solution, your ph will rise. Add more acid solution, the ph will fall. Simple enough? In soap, neutralization for us is around 9, without break down. That's the general consensus in soap making.  Even if you don't get your silly zap, it does not mean your soap is skin safe. Getting a zap or not can be indicitive of any number of other things. But that ph will tell you once and for all whether your soap is truly skin safe. Ive, and several others I've chatted with, had soap not zap me, but ph be too high.

Also, I'd covered many of the misconceptions brought about over phenol-p, which is pink, not red by the way (there is however a phenol-red) , strips and the thoughts of inaccuracy, in another thread:

http://www.soapmakingforum.com/showthread.php?t=43807

When I mentioned the mixing of the 2 solutions, I was actually just in my kitchen working on a small experiment to see if using potassium citrate (KOH + citric acid) would cloud my glycerin method liquid soap( it didn't), as I'm trying to find a way to lessen the amount of soap scum build up in my shower.  I used my phenol-p drops to help me indicate if the combined solutions were in fact neutralized.  After putting several drops on phenol in the 8 ounce solution, and it remained clear, I began adding more KOH.  As the flakes hit, pink would show up, then immediately disappear.  Only when I began to add more KOH to saturate my solution, did it begin to turn pink.  Then i just went a little crazy to see HOW pink it would get.  I got up to almost purplish red, before the color started to fade back to clear again as I continued to add more flakes, thus indicating the ph had gone above 12.  So Phenol drops are quite accurate in indicating ph and lye excess in soap.  Strips are as well, IF used properly.  Just like reading ph strips for pool or aquarium water, where the instructions will say saturate the pads then wait X minutes before reading, but don't read after X minutes (usually 15), the same is said for soap.  You have to let it soak on the indicator pads for a few minutes, then read it.

But, if you prefer to risk chemical burn to your tongue with the zap test, not like anyone can stop you.  just keep in mind, zap test is not really going to tell you if your soap is truly skin safe, aside from the fact that there several variables that effect the zap test, leaving it's accuracy questionable as well.


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## judymoody (Mar 31, 2014)

If you are adding citric acid to interact with lye, you are effectively upping the superfat in your finished soap, as I understand the process.  

It would be interesting to see how pH varies with % of SF/lye discount in fully cured soap.  I have a pH meter but I haven't had the time to do an experiment like this.

To the OP, I'm sorry you threw out your soap.  It was probably OK to use, or it might have been salvageable with a rebatch if there was some sort of measurement problem that was related to the relative purity of your bacon fat.

I pH tested my soap when I first began soaping and it ranged between 9-10.5 depending on the mix of oils I used.  I don't pH test anymore.


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## Gaspar Navarrete (Mar 31, 2014)

lady-of-4 said:


> Actually, ph 10 or above is NOT considered skin safe. Molecular breakdown is occurring, whether you're skin feels it or not. High ph and lye excess/heaviness are synonymous.


 
Now you are making me feel a little queasy :sad: ...

My last three soap batches passed the zap test (no zap). So I took them to be okay, based on what people have told me.  They are curing as we speak.

I also tested the pH of concentrated solutions of each with a laboratory pH meter. The meter said the pHs were 9.7 for the first, 9.8 for the second, and 10.1 for the third (that's around 10)


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## lady-of-4 (Mar 31, 2014)

judymoody said:


> If you are adding citric acid to interact with lye, you are effectively upping the superfat in your finished soap, as I understand the process.
> 
> It would be interesting to see how pH varies with % of SF/lye discount in fully cured soap.  I have a pH meter but I haven't had the time to do an experiment like this.
> 
> ...



The following link, is what I'm experimenting with.  I have only been  making liquid soap since I began soaping 2 years ago.  But it's still  hot process, and honestly, what's in the link can apply to any method o0f soap making.    LS just a little more forgiving.

http://forum.thesage.com/comments.php?DiscussionID=99




Gaspar Navarrete said:


> Now you are making me feel a little queasy :sad: ...
> 
> My last three soap batches passed the zap test (no zap). So I took them to be okay, based on what people have told me.  They are curing as we speak.
> 
> I also tested the pH of concentrated solutions of each with a laboratory pH meter. The meter said the pHs were 9.7 for the first, 9.8 for the second, and 10.1 for the third (that's around 10)



I don't mean to make you upset about this.  But it's a fact, that was stressed to me, not from a fellow soap maker, but from a friend with degrees in biomedical engineering, ie, she's a scientist.  So I'm going to trust what she says, when it comes to the science of what we do, in the chemical sense, over another soap maker, to be quite frank.  Stick with your pH meter.  Make sure it's properly calibrated.  If you can make adjustments to your soap, do so.  If not, learn from it and apply what you learned next go round.    The process of soap making is easy.  But it is a science that not many folks understand, or even care to try to.

In this case, if you're doing hot process, and your ph is still a bit high, you can honestly mix up a neutralization solution and add it to your soap, thoroughly mixing it in. Then just cook it a little longer to remove the extra water you added in.  Or you can leave it as is and go forward with the batch by putting in your additives like scent and color, then molding it.  The little bit of water needed for a neutralization solution is so small, it will honestly further evaporate out as the soap cools and sits out for a few weeks, just like with CP.  Meanwhile, you can still sfely use it, albeit it may be a bit soft.


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## Gaspar Navarrete (Mar 31, 2014)

lady-of-4,

People say that the longer a soap cures, the milder it gets.

Approximately, by how much does the pH go down, after say 2 months of curing ?

If you need specifics, I have an all-olive-oil soap, an olive oil/coconut oil/castor oil soap, and a lard soap that is currently curing. The pH that was measured for each when they were unmolded were 9.7, 9.8, and 10.1 respectively. Where do you think the pHs will be after 2 months of curing ?

Thanks


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## DeeAnna (Mar 31, 2014)

"...Now add more lye solution, your ph will rise. Add more acid solution, the ph will fall. Simple enough?..."

No, it's really, really not that simple. 

Soap is a buffered system, not a straightforward acid-base system, which you appear to think is the case. Furthermore, soap is a colloid, with its own unique chemistry.

The pH of a soap will fall in response to added acid IF and ONLY IF there is excess alkalinity. Once the alkalinity of the system drops to the natural, intrinsic pH of the soap system, the pH will REMAIN STABLE even as more and more acid is added. During this phase, the soap instead will maintain a stable pH by breaking down into its constituent fatty acids as more acid is added -- that is what a buffered system does. Only after the soap fully converts into fatty acid will the pH drop once again in response to additional acid.

****

"...In soap, neutralization for us is around 9, without break down...."
"...High ph and lye excess/heaviness are synonymous...."
"...But that ph will tell you once and for all whether your soap is truly skin safe...."

Kevin Dunn discusses soap pH in Chapter 13 of his Scientific Soapmaking book. In Table 13-1, he states a 1% solution of a pure soap in water will have a pH ranging from 10.1 to 11.4, depending on the soap. See first attached image. 

A mixture of fatty acids will produce a soap that has an averaged pH within the range that Dunn cites. If one cannot accept the fact that a well made, skin safe lye soap may have a pH of 10 or above, then don't make or use lye soap. 

Note Dunn measured the pH of a 1% solution of soap in water. A dilute solution is the correct way to measure pH if one is interested in collecting precise, accurate data. 

If Dunn's research is not sufficient, then check out a study done by dermatologists. The pH of the lye soaps evaluated by these authors ranged from 9.8 to 12.4. See the second attached image. Reference: Baranda, L, et al. Correlation between pH and irritant effect of cleansers marketed for dry skin. International Journal of Dermatology, 2002, 41, 494–499.

Please note the authors measured the pH of an 8% solution of soap dissolved in water. Again, this is a dilute solution and is the correct way to measure soap pH.

And lastly, take a close look at the Walton reference that was cited in the post at thesage.com forum. The pH of the soaps ranged from 9.5 to 10.0 as measured with pH test strips. See the third attached image. Source: http://archive.is/jKKsM#selection-305.0-329.481 

For the record, Dove is NOT a lye soap. It is a syndet (synthetic detergent) cleanser, which is the reason why it can have a pH that is lower than lye soap. To confirm this data, note that Baranda, et al. measured the pH of Dove White and Dove Baby at 7.0 to 7.5. 

****

I've said before and I'll say again -- pick a method, any method -- test strips, phenolphthalein, pH meter, zap test, whatever -- and use it in a consistent way. If your tongue doesn't work right or you don't want to deal with tasting soap, then probably the zap test is not for you, but otherwise it's the best option of the bunch. Get experience and learn how your chosen method performs when testing both skin safe soaps and lye heavy soaps. Don't get hung up on the numbers from a meter or test strip, and don't expect to compare your results with anyone else, because the testing methods are not standardized. Expect when you change the blend of fats in a recipe to get different results. Expect when you make different types of soap to get different results. Just look for trends.

****

The one statement you make that I agree with is that pH is correlated with skin irritation in sensitive individuals. The findings by Baranda et al. support this hypothesis. See the last attached image showing all the cleansers they evaluated for pH and skin irritation.

In their discussion, "...We found a significant correlation between pH and skin irritation (P < 0.006)..." and "...As the soaps more frequently used by the general population showed a high irritation index (3.285–5.4) they should not be recommended for individuals with sensitive skin...."

****

"...In soap, neutralization for us is around 9, without break down. That's the general consensus in soap making...."

Your assertion that this is "the general consensus in soap making" is fallacious. I do not share that consensus, I have presented creditable research data that does not support that consensus, and I do not see a "general consensus" for your point of view in the soapers with whom I interact.

****


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## judymoody (Apr 1, 2014)

Thank you, DeeAnna!


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## The Efficacious Gentleman (Apr 1, 2014)

Great post, DeeAnna.  An interesting read indeed.


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## lady-of-4 (Apr 1, 2014)

Gaspar Navarrete said:


> lady-of-4,
> 
> People say that the longer a soap cures, the milder it gets.
> 
> ...



That all depends your soap honestly dear. Everyone's batch is different. All you can do now is monitor it and take notes.


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## shunt2011 (Apr 1, 2014)

DeeAnna you are once again my hero....thank you for your clear consise presentation. You are so very much appreciated. You make thinks so much easier to understand.  I will contine to use the zap test.  I've been doing it for years and won't stop now.  I figure if I haven't been burned by now it's not happening....


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## Gaspar Navarrete (Apr 1, 2014)

Yes.  Thanks DeeAnna as well.

I did not know that there were some commercial soaps that had a pH of above 9.0.

When I tested a couple of commercial soaps (Dove White and Kirk's castille) and got a pH of around 9.0 for each of them, I started to wonder about my soap (despite it having passed the zap test).

Your article was reassuring.


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## Gaspar Navarrete (Apr 1, 2014)

About your article, DeeAnna

The soap solutions that were tested in the article were 1% and 8% solutions.  I would think that when we are washing ourselves with soap in the shower or sink, we are putting a somewhat more concentrated soap solution on ourselves.

Shouldn't they be testing with say 70% or 80% soap solutions ?


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## lady-of-4 (Apr 1, 2014)

shunt2011 said:


> DeeAnna you are once again my hero....thank you for your clear concise presentation. You are so very much appreciated. You make thinks so much easier to understand.  I will contine to use the zap test.  I've been doing it for years and won't stop now.  I figure if I haven't been burned by now it's not happening....




Actually, she didn't prove, nor disprove anything about the zap test.:yawn:

"No, it's really, really not that simple. 

Soap is a buffered system, not a straightforward acid-base system, which  you appear to think is the case. Furthermore, soap is a colloid, with  its own unique chemistry.

The pH of a soap will fall in response to added acid IF and ONLY IF  there is excess alkalinity. Once the alkalinity of the system drops to  the natural, intrinsic pH of the soap system, the pH will REMAIN STABLE  even as more and more acid is added. During this phase, the soap instead  will maintain a stable pH by breaking down into its constituent fatty  acids as more acid is added -- that is what a buffered system does. Only  after the soap fully converts into fatty acid will the pH drop once  again in response to additional acid."

Actually, it REALLY IS that simple.  You're assumption that I think soap is a simple acid/base solution is interesting...where did you get that from?  Also, you use this word intrinsic in relation to soap.  It's a throw off, as though you think soap has some special internal ph combined with some other ph.  It doesn't.  While yes, each fat will bring something of it's own to the table, including it's own ph, in the end, they all will contribute to the FINAL ph of soap, along with any other ingredients used. It's that final  ph of soap that we are discussing here.  Not it's individual constituents.    Anyways, while yes, in a set of simple acid/ base solutions, as I'd worked with yesterday, the ph will more easily rise and fall with the addition of an acid or base, that doesn't mean the soap won't do so as well with the addition of an acid or base.  In fact, with LS making for example, a common solution with troubleshooting excess fatty acids in soap, (which by the way, if you test ph on will have a lower ph than a fully saponfied soap) is to add more lye, thus fully saponifying the excess fats, and raising the ph.  Or in the case of excess lye, which can only truly be found out with a ph test, is to neutralize it with an acid, thus lowering the ph. By the way, I've zap tested a soap with a known lye excess, and thus, higher ph, nothing. 

When I say neutralization, you must be confused with soap straight out of the pot as opposed to actually neutralizing the soap to a more acceptable pH level.  I was referring to actually lowering the ph to the level that is more acceptable, if at all possible.   In HP and LS making, it is most certainly possible, through the use of neutralizers like borax, boric acid or citric acid.  CP, however, isn't as easy, but it is possible none the less, either through rebatch, or adding an acid during the making process:

http://forum.thesage.com/comments.php?DiscussionID=99

An excess of lye, or hydroxide ions, isn't necessarily needed in this case however, if you just use sodium, or potassium citrate, which can be purchased in anhydrous forms.  Otherwise, the NaOH SAP value of anhydrous citric acid is .625, while monohydrous citric acid is .571

" Again, this is a dilute solution and is the correct way to measure soap pH."

No, it is not the only way. As indicated in the MillerSoap links, the author used BOTH a 1% solution and a slurry.  She made note: "Since most of us [soap makers] don't test pH using a 1% soap solution, I also tested each strip by making a slurry with distilled water directly on the bars of soap. I did each set of tests twice, just to be sure." Her results, using strips and a lab meter, were consistent across the board. 
She further gave simple instruction on the proper way to use strips to get better readings:  

*"Recommendations for using test strips:*
  Some test strips need longer contact with the solution/slurry for an accurate reading. For best results, keep your test strip in the solution/slurry until the color no longer changes, perhaps 30 seconds or one minute.
  Store your strips away from direct light which over time, can fade the dye indicators and interfere with accuracy."


It is also noted that lab grade strips are best.


It's quite contradictory to say this:
"If one cannot accept the fact that a well made, skin safe lye soap may  have a pH of 10 or above, then don't make or use lye soap. "

Then turn around and say this:
"The one statement you make that I agree with is that pH is correlated with skin irritation in sensitive individuals"


You have pretty much agreed that a higher pH results in skin irritation, and is therefore not skin safe, with that last statement.  
As I've said before, a pH of 10 IS NOT skin safe, as stressed to me by friend with a degree is biomedical engineering.  Skin damage is occurring at a molecular level, that is of course most apparent to individuals with sensitive skin.  But it doesn't mean it isn't happening to the general population with normal skin.  Damage is occurring whether it is noticed or not. In fact, considering skin ph is roughly a 5, anything too much higher than that really isn't good for the skin either.  But, in the case of soap, going below 9 is difficult without the soap beginning to breakdown, but that's more likely if you were to a straight acid to the soap, rather than an acid salt, like sodium citrate or sodium borate.



http://skincarerx.com/101-ph-article.html


http://www.livestrong.com/article/152255-ph-effects-on-skin/


In regards to the use of phenol-p drops to test for safety:

http://soap-made-easy.com/soap-ph.html


And technically, on a pH scale of 0-14, 7 being the 'perfect neutral", the scale is actually broken up into 3 parts, or zones, depending on what the source is for the scale: acid zone (0-4), neutral zone(5-9), and basic zone(10-14). With most bodily fluids( stomach acid not included) , and skin, falling in the neutral zone.  Even water, considered to be neutral at 7, depending on temp changes, can be either "slightly acidic" or "slightly basic".  Water at 25*C has a pH of 7, while at 50*C a pH of 6.55. Note, however, that water that has been exposed to air is mildly acidic. This is because water absorbs carbon dioxide from the air, which is then slowly converted into bicarbonate and hydrogen ions (essentially creating carbonic acid).

And I found this website quite interesting, with lessons and tools to help better understand what happens when pH changes.  http://phet.colorado.edu/en/simulation/ph-scale


And more information on the effects of high pH on skin.  



http://www.womensforum.com/alkaline-skin-danger.html


To me, this is no laughing matter, or something to be swept under the rug  We make soap for various reasons, but more likely because we don't want to use synthetic products or there are allergies involved.  Or we just want to know what goes into our soap, to have control.  Just because soap, out of the kettle, automatically has a high pH, does not mean we can't make the attempt to lower that pH to more skin friendly/compatible levels. That to me is not acceptable, and it does a disservice to our families and friends whom we gift these products to.  And if you sell your soap, you are further spreading an issue to customers.  In the old times of making soap, folks then didn't have the knowledge, or ability, to change the harshness of their soap.  To them, it was what it was.  If they zap tested but the soap still "took the hide off of folks", oh well.  We have the means to do better than that. Which is why we have companies like Dove, making the 'perfect neutral soap".  Should the choice be made to find out what those means are as home crafters, that's up to the soap maker.  I'm choosing to educate myself, apply what I know, and further educate new soapers, that zap testing is not acceptable in our modern time as it will not tell you what the pH of your soap is, and a high pH is not skin safe, and that there are ways do the opposite.


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## The Efficacious Gentleman (Apr 1, 2014)

Gaspar Navarrete said:


> About your article, DeeAnna
> 
> The soap solutions that were tested in the article were 1% and 8% solutions.  I would think that when we are washing ourselves with soap in the shower or sink, we are putting a somewhat more concentrated soap solution on ourselves.
> 
> Shouldn't they be testing with say 70% or 80% soap solutions ?



Would that change the pH overmuch?  But more importantly, if you test EVERYTHING in the same manner, be it 80% solution or 8% solution, it is then scientific.  From searching online, it also seems to be the standardised process for scientific testing, so you can benchmark against something.

Don't forget, you wanted to know what the pH of your soap is - and that is not dependent on how much you use when you lather up.  If you want to know if it is safe to use for washing yourself - lick it!


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## Dennis (Apr 1, 2014)

The Efficacious Gentleman said:


> Don't forget, you wanted to know what the pH of your soap is - and that is not dependent on how much you use when you lather up.  If you want to know if it is safe to use for washing yourself - lick it!



Yes, back to the simple, reliable basics.  Although the scientific details are of great interest, many just want to know their soap is safe.  

Beware, no hair is too fine to split.


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## The Efficacious Gentleman (Apr 1, 2014)

I have to point out that this:

_It's quite contradictory to say this:
"If one cannot accept the fact that a well made, skin safe lye soap may have a pH of 10 or above, then don't make or use lye soap. "

Then turn around and say this:
"The one statement you make that I agree with is that pH is correlated with skin irritation in sensitive individuals"


You have pretty much agreed that a higher pH results in skin irritation, and is therefore not skin safe, with that last statement. _

Is akin to saying that if I state that eating peanuts is dangerous for people with peanut allergies, then I am saying that peanuts are dangerous to eat full stop.  It's not.  It's saying it's dangerous if you have an allergy.  If you don't, it's delicious.

Higher pH can cause issues for people who are already sensitive.  DeeAnna did not say that higher pH can cause people who do not have a sensitivity to develop one.

She also did not say that it is the only way to test it - you can lay a litmus strip in the bottom of your mould if you really want to do so - DeeAnna was talking about the accepted method of testing in the scientific arena.  The method of testing that Dove will use when they make their "soap".  Other soapers might well make a slurry or what ever they like - but then you can't hold that figure against those stated by other tests unless they also used the exact same slurry amounts.

DeeAnna - sorry for talking for you - please feel free to put me right.


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## DeeAnna (Apr 1, 2014)

Nope, absolutely no apologies needed. You said it better 'n I could. Thank you, Gent.


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## lady-of-4 (Apr 1, 2014)

The Efficacious Gentleman said:


> I have to point out that this:
> 
> _It's quite contradictory to say this:
> "If one cannot accept the fact that a well made, skin safe lye soap may have a pH of 10 or above, then don't make or use lye soap. "
> ...




I also followed up with: " Skin damage is occurring at a molecular level, that is of course most  apparent to individuals with sensitive skin.  But it doesn't mean it  isn't happening to the general population with normal skin.  Damage is  occurring whether it is noticed or not."  

But you seemed it most beneficial to your argument to exclude that portion.


Bottom line.  Not regulating the alkalinity of soap, regardless of it's inherent cause, will damage skin.  A pH above 10, will never be skin safe.  Sure, you can superfat your soap to counteract/ cover that alkalinity, but it's still there.  And it's stripping the protective acid mantle layer of your skin.

http://chemistscorner.com/cosmeticsciencetalk/discussion/147/how-is-skins-ph-affected-by-the-use-of-soap-ph-9-10/p1


And since this well known crafter is commonly referenced:

http://swiftcraftymonkey.blogspot.co.uk/2010/03/chemistry-of-skin-ph-and-our-skins-acid.html

http://chemistscorner.com/cosmetics...ins-ph-affected-by-the-use-of-soap-ph-9-10/p1


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## Dennis (Apr 1, 2014)

lady-of-4 said:


> Bottom line.  Not regulating the alkalinity of soap, regardless of it's inherent cause, will damage skin.  A pH above 10, will never be skin safe.  Sure, you can superfat your soap to counteract/ cover that alkalinity, but it's still there.  And it's stripping the protective acid mantle layer of your skin.



Now we know what really happened.


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## judymoody (Apr 1, 2014)

I am no chemist, but empirically my CP soap, which falls between 9-10 pH when fully cured, and is superfatted at 8-10%, is gentler to my skin than detergent bars, which dry me out.  It has been many years since I had chemistry in school, so I'm not going to weigh in on the science.  However, based on my personal experience, you can only push the pH down so far before the soap loses its cohesion and ceases to be solid soap.  It doesn't seem worth it to me to tinker in this way for modest reductions in pH when the product has not caused irritation in anyone who has used it.

There are some people who can't tolerate the alkalinity, and for them, a detergent bar is best.  I am not one of those to bash detergent bars for being "artificial."  They have their place.  

Similarly, my hair does not tolerate the alkalinity of CP soap, so I don't use it for that purpose.  For some people, it works great.  For others, it works, if followed by an acidic rinse of some sort.

I also think there is a difference between a rinse off product, like soap, and a leave on product, like lotion, when it comes to acidity/alkalinity.  I believe that's where Susan (Swiftcraftymonkey) is coming from.  She is not a soapmaker, BTW.


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## Sinful7 (Apr 1, 2014)

Dennis said:


> Now we know what really happened.



You sir made me shoot coffee out of my nose! Love this movie


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## lady-of-4 (Apr 1, 2014)

judymoody said:


> I am no chemist, but empirically my CP soap, which falls between 9-10 pH when fully cured, and is superfatted at 8-10%, is gentler to my skin than detergent bars, which dry me out.  It has been many years since I had chemistry in school, so I'm not going to weigh in on the science.  However, based on my personal experience, you can only push the pH down so far before the soap loses its cohesion and ceases to be solid soap.  It doesn't seem worth it to me to tinker in this way for modest reductions in pH when the product has not caused irritation in anyone who has used it.
> 
> There are some people who can't tolerate the alkalinity, and for them, a detergent bar is best.  I am not one of those to bash detergent bars for being "artificial."  They have their place.
> 
> ...



I agree, she isn't a soap maker.  But she is a chemist.  And this is about the basic chemistry of soap, and how it affects our skin and hair.  High alkalinity isn't good for our skin.  So in order to fix that, the need to further neutralize the soap is apparent.

Brambleberry has a tutorial on just this exact thing.  Making a shampoo bar that has a super low pH, and is thus, much gentler on the skin, and hair, than regular soap.

http://www.soapqueen.com/bath-and-body-tutorials/cold-process-soap/sudsy-shampoo-bars/

Where there's a will, there's a way.  That's all i'm saying.  Soap isn't bad.  It's much better than detergent bars.  But what harm is there in making it better.  We have the means to learn and do.  Why not?


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## DeeAnna (Apr 1, 2014)

Judy -- I found myself wondering how our handcrafted soaps would have fared in that dermatology study. Many people, including me, are certain their skin feels better when using handmade soap than when using even the mildest of commercial products.

"...I also think there is a difference between a rinse off product, like soap, and a leave on product, like lotion, when it comes to acidity/alkalinity...."

Yes, I think you are right about this one. Thanks for sharing your thoughts.


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## Lin (Apr 1, 2014)

judymoody said:


> I am no chemist, but empirically my CP soap, which falls between 9-10 pH when fully cured, and is superfatted at 8-10%, is gentler to my skin than detergent bars, which dry me out.


Ditto. I tried many pH neutral detergent bars and liquid body wash (hypoallergenic) and they still dried out my skin and caused irritation. I am eternally grateful for the people that suggested homemade CP soap to me when I vented about becoming allergic to my hypoallergenic dermatologist (MY dermatologist) recommended wash and cream.


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## FlybyStardancer (Apr 2, 2014)

lady-of-4 said:


> Brambleberry has a tutorial on just this exact thing.  Making a shampoo bar that has a super low pH, and is thus, much gentler on the skin, and hair, than regular soap.



Except that the addition of citric acid doesn't lower the pH. It increases the superfat and adds sodium citrate to the bar.


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## judymoody (Apr 2, 2014)

I read that Brambleberrry thread in its entirety, and I am skeptical.  Just because the author asserts that the end pH is 7, it does not make it so.  I suppose I could attempt this recipe for myself and see for myself and I may just do that.  But the conversation below if filled with errors on the part of the OP which gives me pause: for example, because the citric acid is added at trace, that will lower the pH as opposed to simply raising the superfat and producing sodium citrate.  It is common knowledge (thank you Kevin Dunn) that soap batter at trace is still very active, saponification has barely begun, and adding 1% of citric acid then or upfront is not going to make a material difference.  Also there is the dubious assertion by the OP that silicone molds "boil" the soap because it can't breathe.  Last time, I checked coated freezer paper doesn't breathe, nor does wood.  I have seen the pockmarking she describes in silicone molds when doing CPOP, but it has nothing to do with breathing.

While I think that the goal of more pH neutral soap is laudable, I have my doubts that this method is the way to go about it.


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## lady-of-4 (Apr 2, 2014)

FlybyStardancer said:


> Except that the addition of citric acid doesn't lower the pH. It increases the superfat and adds sodium citrate to the bar.





judymoody said:


> I read that Brambleberrry thread in its entirety, and I am skeptical.  Just because the author asserts that the end pH is 7, it does not make it so.  I suppose I could attempt this recipe for myself and see for myself and I may just do that.  But the conversation below if filled with errors on the part of the OP which gives me pause: for example, because the citric acid is added at trace, that will lower the pH as opposed to simply raising the superfat and producing sodium citrate.  It is common knowledge (thank you Kevin Dunn) that soap batter at trace is still very active, saponification has barely begun, and adding 1% of citric acid then or upfront is not going to make a material difference.  Also there is the dubious assertion by the OP that silicone molds "boil" the soap because it can't breathe.  Last time, I checked coated freezer paper doesn't breathe, nor does wood.  I have seen the pockmarking she describes in silicone molds when doing CPOP, but it has nothing to do with breathing.
> 
> While I think that the goal of more pH neutral soap is laudable, I have my doubts that this method is the way to go about it.



^^This is how I can tell no one takes the time to actually look at the link I put up.  Oh well.

Yes, when adding citric acid to any soap, be it a sodium soap, or potassium, the result is a salt of an acid, ie sodium citrate. And yes, if you add it on it's own to your soap, if will essentially superfat your soap, or really, you won't have soap at all.  In that case, you are looking at a chemical reaction something like this:

Lye + Water + Fatty Acids--> Soap

Soap + Citric Acid--> Oils + Salt of Citrate + Water

In the post from The Sage Forum that I linked, once or twice even, it explains that in order to prevent the added citric acid from essentially taking lye away from the saponification process, in the attempt to lower the pH, you must use sodium citrate.  Or create it by combining lye to citric acid in solution.  The chemical equation is this:

Citric Acid + Sodium Hydroxide --> Sodium Citrate + Water + Heat 
C6H8O7 + 3NaOH --> NaC6H5O7 + 3H2O + HEAT 

Essentially, what you will do is 1 or 2 things:  A) do a lye excess that will allow the acid to latch on and convert to a salt of citrate.  or B) Discount your water just enough to set aside and create the appropriate citrate solution for your recipe, and add it at the beginning with your oils, or lye solution.  Or add it in at trace.  If you're doing a liquid soap, you have the aded advantage, once again, to wait unti your dilution phase to make the proper ph adjustments.

I've actually been working on this for the last 24 hours.  Problem is, because I only have phenol drops, I cannot get a reading below 8.2.  So far, my drops have come up clear after working with a 50/50 potassium citrate concentration, at 6ml of solution, added to 2oz of glycerin method liquid soap.  The soap has also remained clear.  There are other folks who are follow what I'm doing, and 1 lady is actually seeing what she can do with baking soda, which she found to thicken her soap immensely, while lowering her pH, and flat lining at 8.5  I can't remember if hers clouded or not.  I'll be working again on this, later tonight, since I took the time to create a full range pH indicator... really nifty watching red cabbage juice change colors the way it did when exposed to different acids and bases.:grin:


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## FlybyStardancer (Apr 2, 2014)

lady-of-4 said:


> ^^This is how I can tell no one takes the time to actually look at the link I put up.  Oh well.



Maybe I didn't look at it when you posted it, but I _had_ looked at that page before, several times in fact! She added it to the unfinished soap, which means it reacts with the lye to form the standard sodium citrate, increasing the superfat.

In order to get citric acid to lower the pH of an actual bar of soap, you have to rebatch once saponification is finished and add the citric acid at that point. That would be closer to the equivalent of adding citric acid to the dilution phase of LS.

Even then, you can only lower the pH of LS to the minimum required to keep the soap salts as soap. Once you start trying to lower it below that point, the soap falls apart (which is what causes the LS to be cloudy at that point). You can't just keep lowering the pH to what you want and still have it be soap.


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## Gaspar Navarrete (Apr 2, 2014)

I am not trying to change the subject of this conversation - this is just a quick sidebar.

Instead of trying to test pH, why not test for any unreacted lye in the soap.

We still keep the zap test, by the way . The lye test would be a supplemental test.


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## lady-of-4 (Apr 3, 2014)

FlybyStardancer said:


> Maybe I didn't look at it when you posted it, but I _had_ looked at that page before, several times in fact! She added it to the unfinished soap, which means it reacts with the lye to form the standard sodium citrate, increasing the superfat.
> 
> In order to get citric acid to lower the pH of an actual bar of soap, you have to rebatch once saponification is finished and add the citric acid at that point. That would be closer to the equivalent of adding citric acid to the dilution phase of LS.
> 
> Even then, you can only lower the pH of LS to the minimum required to keep the soap salts as soap. Once you start trying to lower it below that point, the soap falls apart (which is what causes the LS to be cloudy at that point). You can't just keep lowering the pH to what you want and still have it be soap.



You're back pedaling and repeating yourself, and not paying attention to what I wrote.  I specifically said if you create a solution with lye and citric acid, that can be used as well. A salt of citrate is still created, anf lye used during the saponification process is left untouched.

And actually, yes I can continue to lower the pH to what I want and still have soap. I'm actually close to doing it.  I've managed to lower the ph on one of my soaps down between 7 and 8. Because of my lack of a pH meter, I cannot get an exact number. My only testing mediums available were phenol drops and a red cabbage solution. Please goggle the latter.


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## goteeguy (Apr 3, 2014)

Just read through this entire thread... very interesting information indeed.  (Deanna, I always enjoy your posts!    You are truly knowledgeable, and I deeply respect that.)

All I have to add is this...

We might be talking science here, but lets not over complicate the basics.  People used to render rancid fats kept over the winter months to make their soaps.  They also used to float eggs in shoddy, unregulated lye water produced from ashes in their backyards to test if it was strong enough to use.  So, let's face it, they really had no way of actually testing the PH of their soaps, nor do I think they gave a rats a$$.  And they all lived,... molecular damage be damned!  :crazy:

Just follow a tested recipe... zap test it... let it cure... wash your hands with it... shower with it... and declare it safe for general use.

Ugh!  There's so much more to worry about in life.  Like what scents I should add (and do they contain Phthalates), colours, swirls, embeds, molds...  Oiy!  Testing is the easy part...

Cheers!


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## lady-of-4 (Apr 3, 2014)

Gaspar Navarrete said:


> I am not trying to change the subject of this conversation - this is just a quick sidebar.
> 
> Instead of trying to test pH, why not test for any unreacted lye in the soap.
> 
> We still keep the zap test, by the way . The lye test would be a supplemental test.



No. I'm not getting into a talk  about zap testing .


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## The Efficacious Gentleman (Apr 3, 2014)

lady-of-4 said:


> No. I'm not getting into a talk about zap testing .


 
I am, though, as it was one of the main topics. The pH was asked for in regards to safety, not just for poops and giggles. Therefore, the zap test must also be considered.

*The zap test IS a test for unreacted lye.* 

We have already seen from the posts here that soaps are often above 10pH and are still considered to be safe soaps - by that, they are sold commercially with the pH levels clearly known and accepted and they have no noticable ill effects on the majority of people. 

While it has also been said that soap with a pH over 10 causes skin damage, I think that we can't class soap as unsafe if it is over 10 in the same way that a lye-heavy/unreacted lye soap is unsafe as we can clearly see people using the former with no ill effects (most people, not all) but I don't think anyone could use the latter without skin issues.

So from that, it stands to reason that the pH is not the best way of telling if a soap is skin safe or not. For that, we do need to find unreacted lye. The best way to test that is to zap or use a variation on it:

I personally never put a new soap directly on my tongue. I wet my finger and rub a wee bit and wait. When nothing, I touch the soapy solution on my finger to my tongue. When nothing (other than a soapy/finger taste) I then touch the soap to my tongue. When still nothing, I consider it safe to use. After 2 weeks, I test it on myself and then at 4 weeks would consider giving it to people as presents.

It really depends on what you class as a safe or unsafe soap. I remember the OP was at one point talking about having a soap as safe as commercial soaps. From DeeAnna's post, that means you can go to well over 12pH and still be safe from that point of view, which is at odds with Lady-of-4 who classes anything over 10 as unsafe. When the OP speeks of unreacted lye, we come on to zapping, as commercial soaps don't have any unreacted lye - wouldn't zap you - but are way above 10 on the pH scale.

This is why pH for me is misleading and such a red herring. I will continue to use my little zap process mentioned above, as it tells me for a certainity if the soap conforms to my idea of safe or not.


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## Dennis (Apr 3, 2014)

Enough.


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