Saturday, 16 February 2013

pH Testing - Handmade Soap

  Getting set up with Health and Safety here in Spain has not been easy.  One of the requirements is that each and every batch that is to be sold has to be tested by a lab for certain parameters… two of those parameters are free lye and pH.  Ever had your soap tested officially by a lab?  I bet you would be surprised by the results.  The tonge test is not very accurate…
So the pharmacist that I work with (another health and safety requirement here) is doing some pH experimenting with me.  We are noticing that the pH definitely comes down with time.
We are working with the paper testers and phenolphthalein.  The phenalphthalein basically tells us if the pH is under or over 8.  Under 8 and it comes clear.  Over 8 and it begins to get pink, bright pink still being up there around 10.   But under 8 and over 10 cannot be detected easily with phenalphthalein.  The paper strips do not seem to be very accurate as they are telling me the pH in the photos looks to be around 7 or 8, and the Phen. Tells me it is up near 10!
I have decided to get a more accurate pH (probably a digital one) tester very soon!
I would be interested in hearing your experiences with pH, what pH level is your handmade soap usually at and if you do anything to attempt to bring it down.
Happy soaping!!
Xo
Jen


44 comments:

Tanya @ Lovely Greens said...

EVERY single batch has to be tested? So much for making small batches for the commercial market then. Is the testing expensive Jen?

Interesting that you say that the PH comes down with time. I've always wondered at the 4-6 week cure time. Should you wait four weeks or six and what's the difference in the soap between that time?

Jennifer Young said...

Tanya, EVERY batch needs to be tested. Yes, small batches are not profitable, they are actually prohibitive.... so the small ones are experiments... I think the longer a soap waits, the better it is. I don't think there is a lot of difference between 4 and 6 weeks but there seems to be quite a difference between 1 month and 6 months... in hardness and all around. What are your experiences? xo Jen

Tanya @ Lovely Greens said...

I don't see much difference during 4-6 weeks either and think it must just be for allowing a little more water to evaporate from the bars.

I've always wondered why some makers choose to cure for months though. It does make the bars harder but I've shied away from longer than six weeks myself because I don't want the essential oils to evaporate out of the bars along with the water. I didn't realise that the PH dropped all that much more with time so it makes sense now. Thanks for the info :)

Ambra said...

That is very interesting. I find that I like my soaps a lot better after a few months, but after about a year most of them start to look "old". So my preference it for about 5-12 months. I used to test my soaps for pH, but not any more. I found that ageing drastically reduces the pH.iechta

Suvi said...

From a chemist to a fellow soap maker, I'd say get the digital tester with set buffers to check your pH accurately. Those paper things only work well in a solution, not so well with soap that just forms a suspension. Also, the pH goes down with time, the saponification process takes time to finish (water evaporation from the soap helps it to get there, hence curing time important) and as the last molecules of lye react toe pH goes sloooooowly down.

Connie said...

I sometimes wonder how the generations before us ever lived, without all the regulations of today, LOL. I'm sorry, but I think that there are far more important matters for governments to regulate. Like homelessness, and medical wellness for all there citizens.

Diva Soap said...

Hi Jen,now you made me curious to check Ph value of my old soaps. I occasionally do Ph testing with stripes and the results are always more or less alike, it goes around 9-10 after 3-4 weeks of curing. I recently made a 100% citrus juice soap (i admit, with majority of tangerines juice) and it didn't affect the Ph of soap.
If you want,I will send you an invitation for my private blog,where I write about troubles in soapmaking and this batch was illustrated with photos of Ph stripes. Your mail is preferable to be gmail and I hope I will manage sending you the invitation from my phone (as I've been away from home).
And,by the way,I still haven't,but surely will soon do the lab testing.

Donna OShaughnessy said...

Wow Jen, in the US we have tons of requirements for labeling of so many "beauty" products but simple soap, that made with lye and oil has very basic rules to meet. No pH requirements. Like so many of the others I think my soap hits its prime at 2 months but some gels so well I use it myself in the first week. Would love to know how much the testing costs you

Jennifer Young said...

Tanya, Thanks for your comments... ahhh the essential oils... always a challenge. I find they stay much better if stored in a dark area. xoxo Jen

Jennifer Young said...

Ambra, I agree with you. I like a soap between 5 and 12 months as well. They usually sell before then, but we are using an oldie now that is about 1 and a half years old and we love it. Occasionally a soap will get some spots with age, but only if the SF is too high and there is a high percentage of oils that spoil (avocado, grape seed, rose hip, almond). xoxoxo Jen

Jennifer Young said...

Suvi, Thank you SO MUCH for the info. So nice to get info from a chemist!!! xo Jen

Jennifer Young said...

Connie, Totally totally agree... thank you for your comment. xo Jen

Jennifer Young said...

Diva, Thank you for sharing your experiences! I would be happy to get an invitation to your private blog. Do not have a gmail address. Can it work with yahoo? naturalmentemediterraneo@yahoo.com

xo
jen

Jennifer Young said...

Donna, The regulations here are incredible for soap making and making skin care products. I feel like its even heavier that food!! Send me an email and I will respond with the costs... xoxoxo Jen

Diva Soap said...

I sent it,but I think with other address domains than gmail,you will have access limited to one month,or so. Honestly,I didn't even know you could have a blog on blogger without having a gmail e-mail address.
Btw, what results do you usually get with lab testing regarding Ph values. Do they much vary from your home testing?

Alegria Mediterranea said...

Good subject, I like it!
From my experience I can say this:
1.Everything starts right from the Recipe.
2.The drying period is determined for a good PH(all my soaps,BUT ALL,have a PH=7).
3.For each batch of soap, I made a list and I write the following:date of manufacture,initial weight(for each piece of soap),final weight(after 4 weeks) and the pH.
In this way I managed to select a few good recipes(in 3 years of experience and aprox.300 recipes)with a very very good Ph(because 7 is a very good one).
4.In reality,a complete saponification is when the soap stop to weight loss(the weight remains constant).This means that all the water has evaporated,the caustic soda is completely disappeared(because it works only with water).
In my humble opinion everything starts with the initial recipe conception(the amount of water, of soda, etc.).
Sure there are more elements that influence the finality of a good handmade soap(the drying conditions,the quality components, etc.).
Maybe I was I little help there.
I wish you a wonderful Sunday Day!
Much Love,
Claudia.



Jennifer Young said...

Diva, Thank you so much for the invitation!! I have checked out your post and it is fascinating. I also made soap with whole citrus and it didn't effect the pH much. I think the best thing for pH is curing time... xoxoxo Jen

Jennifer Young said...

Claudia,(Alegria Mediterranea), Very interesting your comment! And fascinating that you are able to achieve a pH or 7 in a cold process soap... after how many weeks of curing? How are you testing? Is it with an exterior lab? Thanks for your comment! xo Jen

Coco said...

Isn´t the high PH precisely what gives the soap its long shelf life? Presenting an inhospitable environment for bacterial growth.

What´s your PH target?

Jennifer Young said...

Coco, Thanks for your comment. I didn't know that but you may be right. My soaps usually have a pH around 9-10, when tested at the lab but it but it can look as low as 7 - 8. I don't trust the strips. The pH in my salt soap is usually lower 8 - 9. Some interesting links about pH in handmade soap:
http://goatmilkstuff.com/Goat-Milk-Soap-pH.html
http://www.millersoap.com/phtome.html
http://www.soap-body-and-spa.com/Cold-Process-Soap-Troubleshooting.html
http://www.chagrinvalleysoapandsalve.com/idascorner/soappH.aspx
http://vermontsoap.com/about-our-soap/ph-soap-and-skin/

I think there is a lot of confusion about pH in soap out there but I am satisfied with pH between 9-10.

What about you?
xo Jen

Diva Soap said...

....dying to know answers!

Alegria Mediterranea said...

Hi Jen,
1.I have already twwo years working with this pH paper test and it works very well(I personally test my soaps).
I bought this paper from specialized laboratories (is expensive but worth it)and in addition I have a few years of experience in chemical laboratory(I worked in a chemical laboratory analyzes outside of Spain).
Although my academic preparation is as Marketing specialist,I did 4 rough years of high school in Chemical industries(from here comes all my thoroughness in all these).
2.Both, the soaps dried 3 months up to 1 year(and more)and the soaps dried normaly up to 4-6 weeks,have a pH of 7.
3.My firm belief is that the final pH level is given by the amount of soda and water attending the saponification process.
I believe that experiment permanently in a very rigorous and methodical process(way) is the key into the success.
Thanks for this post, I am eager to exchange ideas, opinions and experiences really interesting(especially in this area).
I wish you a very,very happy week!
Much Love,
Claudia.





Jennifer Young said...

Claudia, Thank you for your comment and responses!! xoxox Jen

Andrea said...

Hello Jen,

Thank you for sharing this information. This is a very interesting discussion. I tested some Of my soap with the plastic Macherey-Nagel strips mentioned in the millersoap article linked to above. I tested various types of soap and regardless of the recipe they all seemed to test around pH 10. I saw a YouTube video of someone testing their soap using paper test strips. Their soap tested at pH 7. I purchased the strips they mentioned using and tested my soap again. This time the soap tested around pH 7. This seemed strange so I searched and searched the web for an answer. That's when I came across the millersoap article. The article made sense to me so I accepted the Macherey-Nagel test strip results as being the more accurate.

Jennifer Young said...

Andrea, Thank you for commenting!!! I have another post on pH (later), don't know if you read it, but after testing with my pH meter. I believe hand-made soap should come in around 10pH and I am okay with that for now. So interesting to hear about your results as well. xoxo Jen

Wendy Gardner said...

Hello, I just did my first pH test on a bar that is almost 7 months old using a (buffer checked) digital meter - results 9.95pH. The recipe was checked on soap calc and contains essential oils and honey. I was very surprised at this. Was expecting something closer to neutral.

Jennifer Young said...

Wendy, I know. I think a lot of soapers think their soaps have a lower pH because they use unreliable testing strips. But your pH sounds accurate to me and just about perfect, in my opinion, for a handmade soap!! Thanks for contributing. I am really fascinated to hear other people's results and love when other soapers realize the truth about soap pH. xoxox Jen

Marsha said...

I'm sitting back trying to find ways to lower ph in my soaps, and having heated debates with fellow Soapers left and right about the accuracy of tongue testing soap. I even made a point that if here in the US, if we were required to have our soaps tested for safety prior to sale, zap testing would be nixed. Thank you for your post. You just proved my points. May I ask what pH is acceptable in your country?

Marsha said...

.

Anonymous said...

makes sense as the skin can dissolve with excessive lye and in extreme cases burn.I BELIEVE a ph of 9 to 10 is acceptable as this has antibacterial and cleansing properties lower than this is sludge soap with unspent oil.Also noticed that soap ph does lower with age .Cutting the soap into reasonable size bars and airing it will eventually turn lye to a carbonate

Jennifer Young said...

Marsha, a pH of up to even 11 is acceptable here. Sorry it has taken me so long to respond! xo Jen

Marsha said...

Woods! That's high! There's no way to tell if that is unreacted lye or just the natural fatty acid profile creating that high of a pH. May as well wash with commercial laundry detergent or ammonia even. I'd er on the side of caution and keep soap below 10 or as close to neutral ad possible. Thanks for answering.

Jennifer Young said...

Ours is almost always between 9 and 10. Sometimes a little lower, sometimes slightly higher, but the lab accepts up to 11ph as acceptable for the skin. I don't think it would be the same as washing with ammonia or laundry detergent.... have you ever had an external lab analyze your ph? The results are SURPRISING!!! We have to have each batch tested. As you can see on my follow up post http://jenorasoaps.blogspot.com.es/2013/05/ph-handmade-cold-process-soap-and.html another soaper posted her external lab results and they were higher than 10. Let us know if you every get an external analysis!! xo Jen

Marsha said...

I've finally concluded my experiments on dropping pH to a more neutral soap. 11 just isn't safe for the skin, no matter what a lab says. I use a 2 point calibrated pH meter on my soap.

Jennifer Young said...

Marsha, I would love if you could share how you drop the ph in your soap bars, something that has never been as easy for me as manipulating the pH in our liquid soap (usually between 8.5 & 9). We also use a 2 point calibrated pH meter, but the lab always tests higher. i think it is more about the way they test than what instruments. How do you usually test pH of your bar soap? Thank you for your comments!! xo Jen

Marsha said...

Sadly I don't do bar soaps. I'm Liquid soap exclusive. I actually posted the conclusion on my YouTube channel yesterday and I do know many varieties soapers who get their ph down that far as well and they gave me some pointers throughout my work these passed few months. Using additives like citric and stearic Acid lowers pH. Coupled with extra function stearic has on hardening soap, which I believe is also a function of sodium lactate if it's added to lye solution, you're less at risk of having mushy soap caused by the extra superfat that comes with using the acids. You can also use salt to harden, and counter this effect. Another way, which I'm going to test next is to use a larger superfat up front, since the free fatty acids will effect final ph as well. My hardest part wasn't lowering pH, rather making sure my free fats were solubilized in my liquid soap.

Jennifer Young said...

Marsha, Thanks for all the info! I so rarely check this blog lately that it was great to find you here. As for citric acid, that is how I lower the pH in our liquid soap but it has had no effect on by bar soap in my experiments. My salt soap bar always has the lowest pH... I do use Sodium Lactate which has helped hardness as I don't use palm oil. An issue with bar soap is not just mushy soap but oils going off as well with higher SF. We thicken our liquid soap with sea salt. Thanks again for your comments! xo Jen

Marsha said...

To counter the rancidity of the higher superfat, have you tried and antioxidant like Vitamin E?

Jennifer Young said...

I have... both Vitamin E and Grapefruit Seed... but the higher the sf, the shorter the shelf life. No matter what they say, it is VERY tricky to lower pH in bar soap. So simple in Liquid soap... just made a big batch of liquid soap today and was thinking about this thread as I lowered the pH.... anyway, thank you for your input. This is what I enjoy most about this blog. The sharing of ideas. xoxoxo Jen

Marsha said...

Pick up the book Scientific Soapmaking by Kevin Dunn if you haven't already. I'm just about to crock open my new copy now, so this will be an interesting few weeks as I relearn chemistry terminology and apply it to soap.

Jennifer Young said...

Marsha, Thank you so much for the tip!! xoxo Jen

Marsha said...

Totally welcome! You should come over to the Facebook group, Liquid Soapmakers. Might help you fine tune some stuff, if you're like. We're always experimenting and trying to keep up to date on new methods and such.

natalia said...

i wish i knew what to do to get a ph=7 because i feel mine ph between 9and10 very drying in my skin. I already worked with 5 and 7% superfat and also different discount of water. also cp and cpop (40% caustic solution) ... nothing seems to give me a different ph...

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