# How does the zap test detect lye (vs pH)?



## JayJay (Apr 8, 2015)

Hi There-- I'm a beginner (I like to lead with that so people forgive my lack of understanding) 

My question is about a theme I've in some threads regarding pH testing methods versus lye testing.  There seems to be a consensus that zap testing is a test of excess lye remaining in a soap, rather than a way to test pH.  Did I get that right?  If so, how is this the case?  Isn't the zap from soap the same zap that we get from batteries? Battery zap is due to alkalinity, right? 

I thought that lye pushes the pH range so high that it zaps. Is this wrong?

I'm no chemist. I remember VERY little chemistry from the classes that I took in school. And I have been making some for just a little while.  So if anyone can chime in and help, I would appreciate it.


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## zolveria (Apr 8, 2015)

Some one Correct me if I am wrong. 

This is how I can explain it. when you taste soap it should have a soap sweet taste. well to me it is sweet. I like the soap taste.
When it is not done. It will taste like a 9 volt battery taste when you stick against your tongue.  Hope that helps.

My suggestion is. when you cut your soap after sapon has been reached. save a scrap for yourself.  use this to cut slither and taste them with the tip of your tongue normally sapon is reached after 24h. the curing is to harden the soap so that it is at its fullest potential when it come in contact with water. IE it would last longer.


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## jules92207 (Apr 8, 2015)

I describe zap like pop rocks. Its a slight shock, it's intensity depends on the potency of lye left in your soap. You can have lye crystals, lye weepy water, etc. If you are going to zap test I would be near a water source to rinse quickly after if you get a zap.


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## zolveria (Apr 8, 2015)

perhaps i have never gotten zapped... aww shucks.. alls well in soap and lye


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## Susie (Apr 8, 2015)

Zap is a sensation, not a taste.  All it tells you is safe or not safe.  Does it still have excess lye that will harm skin if used?  But, at the end of the day, that is exactly what I need to know before shipping soap off to family.  I zap test, and let others obsess about pH.

ETA-Please note that zap does no permanent harm to your tongue.  It does not poison you.  It does not harm you in any way.  It just gives you a brief jolt that says it needs more time.  That is all.


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## The Efficacious Gentleman (Apr 9, 2015)

Aye, I have done more damage eating something that was too hot and burning my mouth than I have ever had from zap testing - and I've had a fair few zaps, a lot of them hefty ones 

The zap test measures EXCESS alkalinity while the pH tests measure how alkaline something is. Every soap will have a certain pH rating (always more than 7, no matter what some might think) but it will vary from recipe to recipe so unless you benchmark each recipe you make, the pH is not an ideal way of measuring safety. 

Regardless of the soaps pH, the zap test will tell you if it is safe quickly, easily and efficiently.


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## galaxyMLP (Apr 9, 2015)

Also, battery zaps are due to an electrical discharge from the electrolytes in your saliva completing the circuit. It is not due to alkalinity. In soap, it is. Believe me. You know when you've been "zapped" by soap and it is no fun.


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## JayJay (Apr 9, 2015)

Thanks everyone! Question answered.


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## ngian (Apr 9, 2015)

The Efficacious Gentleman said:


> Regardless of the soaps pH, the zap test will tell you if it is safe quickly, easily and efficiently.



So when you get a zap feeling from a soap and then you use a pH strip on its lather, you can get a PH from 7 to 12 PH scale, meaning that you can get zapped with low PH also?

Nikos


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## Dorymae (Apr 9, 2015)

ngian said:


> So when you get a zap feeling from a soap and then you use a pH strip on its lather, you can get a PH from 7 to 12 PH scale, meaning that you can get zapped with low PH also?
> 
> Nikos



Nope it means that PH strips don't work for soap!  No soap would ever be a PH of 7, it is simply chemically impossible.

What it means is that soap will have a PH of between 9-11 and be perfectly safe IF it passes a zap test. 
PH tells you nothing about the safety or whether there is still lye in your soap.


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## Susie (Apr 9, 2015)

You need to wrap your mind around one fact:  pH does not tell you if soap is safe.  Period.  

Even if you could measure it accurately, it still does not tell you if the soap is safe.

This seems to be one of the hardest concepts to get across to newer soapers.  I get that we all want to be as scientific as possible to achieve the best outcomes.  This is a good thing.  But pH is not going to answer the question you need answered most...Is it safe?


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## The Efficacious Gentleman (Apr 10, 2015)

ngian said:


> So when you get a zap feeling from a soap and then you use a pH strip on its lather, you can get a PH from 7 to 12 PH scale, meaning that you can get zapped with low PH also?
> 
> 
> 
> Nikos




To carry on from dorymae, it also means that the method you are using to measure you pH is wrong - another reason why pH measuring is a problem in soaping circles: not everyone has the proper equipment and measures in the correct fashion, so a lot of the numbers spoken about are wrong before we even start to consider what pH might be able to tell us.


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## ngian (Apr 10, 2015)

Thank you for your answers while I want to correct me on the way I have measured PH. I dilute a little soap in little water and then I sink the strip in it, not in the bubbles (if there are any). 

So zap happens on excess lye,  due to wrong quantity in the recipe (used more lye than all the oils needed) or when saponification isn't over (the lye boys haven't paired up with the oil girls yet)? 

As I always do gel my soaps with CPOP I guess that I force all the boys to pair quickly, so when I unmold the soap it will zap only if I have used more boys than girls at the party?


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## hmlove1218 (Apr 10, 2015)

Theoretically, yes. Even if a CPOP soap zaps right after cutting,  I would give it a few days and test again before rebatching it.


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## Susie (Apr 10, 2015)

ngian said:


> Thank you for your answers while I want to correct me on the way I have measured PH. I dilute a little soap in little water and then I sink the strip in it, not in the bubbles (if there are any).
> 
> So zap happens on excess lye,  due to wrong quantity in the recipe (used more lye than all the oils needed) or when saponification isn't over (the lye boys haven't paired up with the oil girls yet)?
> 
> As I always do gel my soaps with CPOP I guess that I force all the boys to pair quickly, so when I unmold the soap it will zap only if I have used more boys than girls at the party?



See, to start with, you can't just dilute "a little soap in little water".  You must have precise amounts of each, or it is not correct.  Even then, it will not answer if the soap is safe.  

The answer to the next two is yes and no.  Yes, zap is when you have used more boys than girls, or if the saponification is incomplete.  And no, CPOP gets you gel, but that does not mean saponification is necessarily complete(it should be, mind you, but there is always the possibility that it needs a few more hours).


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## Chefmom (Apr 11, 2015)

Recently my husband bought me a tablet and I naturally got the amazon kindle app for it.  And was tempted to download a bunch of free soap and bath a body books.

Yea.  the first one I skim read is called "Soap Making.  How to make soap quickly and professionally at home...(soap making for beginners)"  Soooo naturally one could think that it is a good beginner walk through the soap world.  In reality it is the most disjointed thing I think I've ever read.  And since its free, many people will gladly believe what it says.  Yes it has the basic info on cold process soap, once the curing the soap info comes up it "clearly" states that cold process soap needs to cure between 4 days to 4 weeks.  Yea...so clear.  The author brings up ph testing and states that this is necessary for all soaps to determine safety.  It helped me to believe that this is why SO MANY people seem to bring up ph testing again and again and again.  There are books out there telling them to, there are soap makers out there on facebook pages, in blogs, in videos telling them to.  Period.

Another great point >>insert sarcasm here<< is once the basic info in this book is done and the "5 amazing recipes of natural soap" part comes up....the first recipe is a melt and pour recipe.  M&P was never discussed in the book up to this point...okay move onto #2 amazing recipe....and you have a 100% coconut oil soap (for laundry soap) that is cooked in a pot on the top of the stove, hot process style.  And yes, hot process was also never discussed in the book.  

So, as long as freebie books and other people who keep repeating this poor information are out there......seasoned soap makers are going to keep fielding these type of questions...


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## Dorymae (Apr 11, 2015)

Yup and this is why it is important that we say it over and over whenever we encounter the PH question. 

Simply stated if you are making bar soap and think PH has anything to do with safety, it is incorrect. As a matter of fact IMHO if you make bar soap you should not bother will PH strips, meters, or drops. It is a waste of time, money and energy and will inevitably lead to your thinking you have a "bad batch" when in fact there will be nothing wrong. A lot of worry, confusion, money, and time wasted for nothing.

Learn to zap test, it's free and will tell you immediately if there is a problem.


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## not_ally (Apr 11, 2015)

There are a lot of bad books out there, and some good ones (I think I have the good ones and also a few of the bad ones.)  IMO, the best thing a beginning soapmaker can do is join a good board, read and research (a lot) on basics, use a good calculator before making any recipe (the sage or soap calc ones are my go-toos) make a batch, research on the stuff that does not work out, make another, research again, make another batch, research again, maybe repeat a few more times, and then start asking questions. You don't even know what the questions are, or how to make sense of the answers, unless you have put in some work.


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## JayJay (Apr 12, 2015)

[COLOR="[/COLOR][quote="not_ally, post: 508003"]There are a lot of bad books out there, and some good ones (I think I have the good ones and also a few of the bad ones.)  IMO, the best thing a beginning soapmaker can do is join a good board, read and research (a lot) on basics, use a good calculator before making any recipe (the sage or soap calc ones are my go-toos) make a batch, research on the stuff that does not work out, make another, research again, make another batch, research again, maybe repeat a few more times, and then start asking questions. You don't even know what the questions are, or how to make sense of the answers, unless you have put in some work.[/quote]

I agree. I made three batches before I discovered this board. The first one was done from a video that oversimplified the process. The soap from that batch soap never actually turned to soap. I end up dumping it.  The second batch was done from a recipe posted on a DIY blog. It did turn to soap but it zapped me so I thought it was a fail and I rebatched it less than 24 hours later. (I didn't know any better.) The third batch was a recipe from the blog of a person who used to sell soap. That batch turned out ok, thank goodness. 

None of these batches went through soap calc. I didn't know how stupid this was until I found this forum. 

There is so much to learn but it's good to know that people on this forum will tell me the truth. 
Thanks for that. I love the soaps that I have made since I discivered this group.


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## Susie (Apr 12, 2015)

JayJay said:


> [COLOR="[/COLOR]
> There is so much to learn but it's good to know that people on this forum will tell me the truth.



Thank you for saying that!  We had a few folks this year that did not appreciate hearing the truth, and took it as a personal attack.  It is good to know that we have helped someone!


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## jules92207 (Apr 12, 2015)

When I started soaping a friend taught me and I went and found the same book she had cause I didn't know any better. I just wanted to do it "right". Looking back most of the recipes I made from that book were not ideal and once I found this forum I haven't opened that book since.


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## JayJay (Apr 12, 2015)

Susie said:


> Thank you for saying that!  We had a few folks this year that did not appreciate hearing the truth, and took it as a personal attack.  It is good to know that we have helped someone!



You all have helped me (and protected my unsuspecting friends) by explaining process and cautioning me. 

Fortunately I have grown a pretty thick skin over my lifetime. I much prefer to hear the truth from some helpful people than to be told how "easy" something is by someone who is just trying to maintain their readership. This isn't a dig at the bloggers out there, but I know that they can be pressured to keep new and exciting material for their readers. Sometimes that means writing about subjects without much expertise to back it up. It happens. Actually in this case I am glad it did happen because if she hasn't made it seem easy, I would have never tried it. Soaping is now by far my favorite hobby.

A while ago, I did some research on selling a hair product that I make for myself and my friends. One of the things that I read is that there are few things more brutal than online reviews. It's best to hear harsh realities about your product BEFORE putting it out there for others. Your friends and family will tell you that it's great, but the online reviews will point out that it smells bad, or feels unpleasant or is not worth the money etc.  You can go back and make improvements but the bad impression is still out there and almost impossible to overcome.   Even though I am not selling my soap, I am still thinking of it in the same way-- thanks to you all. If I had given my friend's toddler that first eczema soap recipe I devised, I could have made the poor baby's condition flair up.  I am glad you all stopped me.


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## Jstar (Apr 14, 2015)

Ditto to Susie's comment.

Also to add, there is ALWAYS something more to learn as I have found here, and I am honored to be in such a truly caring soaping community as this. Even tho Im 3 yrs in to my soaping now, I still value every one of the more experienced soapers guidance. If I want to know something, this is the place I know I can come and get honest answers.


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