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How long until CP soap should be neutral?

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renee_soap

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Hello all! So, I made my first batch of CP soap about 4 weeks ago. I just jumped right in and unfortnately I know now that I made quite a few mistakes in my first batch: used a recipe that just used volume measurements instead of weight measurements, doubled the recipe haphazardly, stopped stirring after an hour to run out to get a stick blender, then forgot to wrap it in a towel for the first few hours.

So, all in all, I wasn't going to be surprised if it turned out to be a disaster, but I was still cautiously hopeful.

Since then, I did a lot more reading/research and made a new batch this past Sunday, with (what I believe) was much better technique.

Today I got in the mail some phenolphthalein that I had ordered, and I went to test my first batch and unsurprisingly it turned bright pink. But then when I went to test my second batch, from just three days ago, it didn't turn pink. Is it possible that this batch is already neutral, or did I maybe do something wrong with that second batch?

Also, is there anything I can do with my ruined first batch or should I just throw it away? I took a shower with it earlier this evening (when I first did the test with the phenolphthalein it didn't change colors right away so I thought it was fine!)--it didn't burn my skin or anything, and it definitely felt like it was cleaning me! I hope there will be no negative repercussions to this?

Any advice is appreciated!
 

snappyllama

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Howdy and welcome to forum!

To test to make sure soap is safe, you'll want to zap test it. There is a sticky showing a how-to, but basically you build up a lather and taste it. If nothing feels electric, put a bar in your mouth. If you feel an electric zap - there is still active lye. Drops and pH testing don't really give good results in soap making. Depending on recipe and whether a batch gelled, it can stop zapping when it's cut or take a few days more.

You're right about not using volume measurements. Soapers weigh everything. It's the only way to be precise.

For every recipe from any source, you'll want to run it through a lye calculator yourself. Typos happen.

It's okay to test soap on yourself after a few days, but you'll want to avoid hopping in the shower with it in case there is something off. It's better to notice an issue with suds on your hand rather than other places. All soap greatly benefits from a good cure, 4 weeks is typically the minimum. It will become sudsier, longer lasting and much more mild. Even a fantastic recipe can irritate when it's fresh.

I'd hang onto the first batch for a few weeks and cautiously zap test it. If it keeps zapping, I'd chunk it since there is really no way to know what is off to rebatch it successfully.

You only need to wrap a soap up if you want to gel it. There are a bunch of posts on gelling versus not gelling if you search on the forum.
 

IrishLass

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Hello all! So, I made my first batch of CP soap about 4 weeks ago. I just jumped right in and unfortnately I know now that I made quite a few mistakes in my first batch: used a recipe that just used volume measurements instead of weight measurements, doubled the recipe haphazardly, stopped stirring after an hour to run out to get a stick blender, then forgot to wrap it in a towel for the first few hours.
Welcome Renee! :)

Well, at least you got most of the mistakes covered in your very first go! lol



Today I got in the mail some phenolphthalein that I had ordered, and I went to test my first batch and unsurprisingly it turned bright pink. But then when I went to test my second batch, from just three days ago, it didn't turn pink. Is it possible that this batch is already neutral, or did I maybe do something wrong with that second batch?
Lye-based soap will never have a neutral pH. By definition, soap is an 'alkali salt of a fatty acid', which means that if it ever tested out as neutral, it would have lost it's ability to cleanse and would no longer be soap. The pH will always come to rest on the alkaline side- somewhere between 9 and 12.

The color range for phenolphthalein that I have in my notes is that it is clear from 0 to 8.2, turns various shades of pink from 8.2 to 12 pH, and then again goes clear when greater than 12 pH. It's much more likely that your newest soap that tested clear actually has a pH of over 12 rather than being under 8.2.

But testing for the actual pH of lye-based soap is not so much as important as the testing for unreacted lye, which is the real indicator of whether your soap is actually safe to use or not.

For example, it's possible to have a soap with a pH of 9 that's unsafe to use because it has unreacted lye in it, but by the same token, it's also possible to have a soap that tests out at a pH of 12.35 with a pH meter that has no unreacted lye present, and is perfectly safe to use (ex: Johnson's Baby Oat soap).

I know that lots of soap blogs and FB groups put their stock in testing for pH, but it's really a waste of time/money and doesn't really tell you much of anything in the end. The best test to conduct on soap is the zap test (i.e., tongue test), which will tell you if your soap has any unreacted lye in it.... which Steve provided a link to in his post.


Also, is there anything I can do with my ruined first batch or should I just throw it away? I took a shower with it earlier this evening (when I first did the test with the phenolphthalein it didn't change colors right away so I thought it was fine!)--it didn't burn my skin or anything, and it definitely felt like it was cleaning me! I hope there will be no negative repercussions to this?

Any advice is appreciated!
I would not say that your first batch is ruined at all, and I personally wouldn't chuck it. Instead, I'd check for zap, and if it doesn't zap, it is fine to use. :)


IrishLass :)
 

DeeAnna

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I agree with the advice everyone has given you.

I just wanted to also add that putting drops of phenolphthalein solution on a bar of soap is an inaccurate way to evaluate pH. I know soapers claim that the intensity of the pink is related to the pH of the soap, but most chemists would cringe at this idea.

pH is a measurement of the hydrogen ions floating around in a water solution. When you add a few drops of phenolphthalein solution to a dry soap bar, it's anybody's guess how many hydrogen ions from the soap will end up in the solution, because there are many variables that can affect the number of ions released from the soap.

For example, phenolphthalein solution tends to show no color or only show a faint pink on an older soap bar, but it often flushes a darker pink on a newer bar. Why is that? Most soapers would say it's because the older bar has a lower pH, but that's not necessarily true. It's a pretty good bet that fewer ions will be able to "float" away from an older bar of soap into the phenolphthalein liquid compared with the number of ions that might be able to float away from a freshly cut bar.

That doesn't mean the older soap definitely has a lower pH, however. The older bar might indeed have a lower pH, but the color change (or lack of color change) might be due to the different moisture content of the two bars. Or it might be related to the more organized crystalline structure of the cured bar versus the more random structure of the uncured bar. Or it might be from the different blends of fats you used to make the two soaps, if you used different recipes. You just don't know -- and that's the problem.

The same is true if you see a ring of darker pink around the edges of a phenolphthalein droplet -- it's telling you there's a variation in the ion concentration, but how can you tell if that's important or not? More ions = darker pink. But what is causing it? You don't know -- and that's the problem.

And time and temperature affect this -- More time to leach ions away from the soap = darker pink. And higher temperature => higher the apparent pH. Is this a legitimate concern? Again, you don't know -- and that's the problem.

That's why using phenolphthalein solution on a soap bar (or on a dab of liquid-soap paste) is not a good test.
 
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renee_soap

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Thank you so much @Steve85569, @snappyllama, @IrishLass, and @DeeAnna! All of your responses have been very educational.

It's interesting to hear that phenolpthalein isn't very accurate for soap bars--I have Alicia Grosso's "The Everything Soapmaking Book" which advocated for using it, so now I'm wondering if perhaps some of the other info in there may be incorrect? She doesn't mention the zapping test.

So I did try the zapping test with my older batch, and when I first very gingerly licked it, I didn't really notice a zap, so I was perhaps a little overenthusiastic and put half the bar in my mouth, which left my mouth burning for the next hour or so... So I'm not really sure what that means? I have also showered with the soap a few more times since then, and it felt totally normal on my skin--nice lather, no itching, no burning, definitely left me clean. What would the negative effects be of using a soap with too much lye in it? Would I have noticed? Is it risky to keep using this soap?

Thanks again!
 

Seawolfe

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Zap is a feeling, an involuntary reaction, not a taste. Of course soap tastes nasty!

Lots of very good books were written by pioneers in home crafted soap, but their information can be out of date, or they lack an understanding of some chemical nuances.
 

DeeAnna

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"...What would the negative effects be of using a soap with too much lye in it?..."

Um, well, my answer comes from embarrassing personal experience when I was an utterly newbie soaper, but ... I can say from experience if you shower with a slightly lye-heavy soap, your skin will itch like crazy for a few hours. A little more lye heavy and I imagine (don't know THIS from personal experience, thank goodness) that the itch would turn into a serious burning feeling.

Dampen your fingertip, swipe it on the soap, and very lightly touch your fingertip to your tongue. That's a cautious zap test.

If you do a cautious zap test like this, and the soap is lye heavy, even slightly, you won't have to ask yourself if it zapped. It's unmistakable and immediate.

If you find yourself wondering or if the reaction takes a bit to happen, you're probably reacting to the taste of the soap itself or some of the ingredients in your soap. Fragrances can be nasty tasting even though they might smell wonderful.

In any case, if there's any kind of unpleasantness going on in your mouth, spit, don't swallow, and rinse well with cool water until the unpleasantness is gone.
 
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Susie

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Your soap will also get milder with a proper cure. 4-6 weeks is usually minimum, unless you have a high OO soap. Then you are talking 6-12 months.
 
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