Natural soap? PH? Why is it important?

Behind the front counter at Bath Boutique is a whole other world... a messy one, a world I absolutely LOVE.  It has been my passion since 2005 to make soap, I have learned a thing or two,  and I have my preferences for oils I use, and techniques I use.  One habit I developed early on in my soapmaking journey was testing for ph or the alkalinity of the soap I make.  It was important to me to ensure that what I sent out to my customers was not just beautiful, but effective, and safe. So let me tell you a bit about the ph level in soap, what it is, what is isn't, and why it's important.

First of all, lets talk about your skin - in the grand scheme of things, neutral ph (or the middle point between alkalinity and acidity) is 7; 14 is top end alkaline, and 1 is the lowest ph level, or the highest acidity level.  Our skin sits slightly below the halfway mark, mine is between 5 and 6. This will vary a little bit as everyone is (slightly) different. Excuse the "soap speak" but the oily layer that protects the largest organ of our body is called "sebum" it keeps our skin healthy, hydrated, and protects it from the environment. 

Very basic ph test kit.

My own skin ph level

When we use soap to wash our skin, the ph is important because we don't want to strip our skin and leave it red and raw, and tight feeling. But if the ph level is too high, this is exactly what will happen, but it has to be slightly above neutral in order to lift the dirt away. Soap, of necessity, and by definition is alkaline. We use the chemical sodium hydroxide (for making solid bar soap) to rearrange the properties of chosen oils to give us our salt/water/glycerine product that we know as soap. Without getting crazy technical and losing your interest, sodium hydroxide breaks up the fatty acids or triglycerides of our oil - neutralises the acid, and leaves us a hard bar that is alkaline enough to remove dirt and oils from our skin.  If it is TOO alkaline - it might remove a bit of skin and some flesh as well - and we don't want that!  

So when a batch of soap is freshly made, the sodium hydroxide is doing it's job to rearrange things and so the ph reading can be very high - and that's why we let soap "cure" - basically we are letting it do its job, and when it's completely finished having it's chemical reaction - we SHOULD be left with a soap that is alkali enough to remove dirt and unwanted oils without damaging the skin, allowing the sebum to coat the skin again, and the cycle of cleaning and protecting goes on.  I usually explain the chemical reaction process of making soap like having the cleaners come to your house. If you have a cleaner, (I don't, but I imagine this is how it would be!) you leave for work, your house a bit of a mess, things out of place, not looking it's best, but when you get home, everything has been rearranged, put back in their place, all clean and tidy and ready to be enjoyed... and the cleaners are gone.  It's the same with soap - we add the sodium hydroxide to the oils, they get in there and do their rearranging, making things perfect, and when they have gone, you have a lovely smelling, safe, useful and wonderful product to enjoy. 

Click on the images to read about each ph level.

Just as an aside - if a "soap" has been balanced so the ph level is 7 - or neutral, it actually is no longer classified as soap. So soap by definition is alkali.  I won't send out my soaps until the ph level is 8 or lower - many commercial soaps have ph levels of 9 or higher, which will not feel good in the long run for your skin. There are many things that can affect the ph level of the soap, the amount of sodium hydroxide used - each oil has a different requirement for breaking it down, so what is used for one oil, may be too much for another oil. The percentage of oil that actually gets broken down by the sodium hydroxide (this is called a lye discount and is represented by a %) so if a soap has a discount of 5% - it means that only enough sodium hydroxide has been used to break down 95% of the oil, leaving 5% in it's unbroken state.  I could go on and on and on about soap, the technical process, the discounts, the oils, the length of time curing - hot process vs cold process.... but I think that's enough for today!