What is pH?
This blog post is going to be all about pH. There is going to be lots of information to cover. I would recommend getting a notebook and a pen or pencil to write information down.
pH = -log [H]+
This equation is used to find the concentration of hydrogen ions. So, essentially pH is the concentration of [H]+ ions and [OH] - ions.
Looking at the chart it shows us a couple of things.
0-6 = acidic
7 = neutral
8-14 = alkaline
The more acidic a solution the higher the concentration of [H] + ions. The higher the concentration of [OH] - ions in a solution would make the solution more alkaline. I also want to point out that pH is only in aqueous solutions. Which means the solvent is water. So, that means oil/butters and waxes do not have a pH. This will be important for the next couple of topics,
Ok! I get it know there, is a lot of fancy science involved. How does this apply to what we are doing?
let me explain.
We need to know the pH of our products for a couple of reasons:
1. We want to formulate according to where it is going to be applied:
For example, our skin is around 5.0-5.5. So, we want to formulate around range. AS long as it is in that range then it is fine. Essentially we want to make our skin happy
Our tears have a pH of 6.5 to 7.6. So, for eye makeup removers and eye creams need to be formulated around there. So our eye don't get a chemical burn. (Link)
For hair formulation it can be from 3.67 to 5.5 according to this article (Link)
Our skin does adjust it self to be the normal pH so don't worry if an acid serum has a pH of 3.5
A pH this low will encourage peeling. This is the best pH for acid formulations
2.Certain ingredients require a certain pHs
One of the most common examples is preservatives. Most suppliers provide this information of the certain pH range that it is effective in.
So, let's put this into context. let's say you have a formulation of a Acid toner. After taking the pH of the toner you find it is at 2. let's say the ideal pH is 3.5. Your preservative says the pH needs to be between 3-7 to be effective. To resolve the issue you would need to add an alkalizing agent to the toner to bring the pH up. Typically it would be a NaOH solution at 30%. Add one drop at a time. Make sure to get a fresh strip every time. If you are using a meter. Get some distilled water to store the meter in. (if you have not done it in a while or you just got it then don't forget to calibrate it. I have how to do it on my Instagram in my highlights. (link) simply swirl it around and write down the value
Great, Videos on how to check and adjust pH:
3. pH is never constant
Meaning if you make the same formula with all the same ingredients and equipment.. All of the products will have slightly different pHs.
This is why in most formulas at the bottom it will say "pH adjuster q.s" .
Q.s. means 'quantium sufficient'
Which is latin for as much as needed..
It is because we can't say that 0.5 % citric acid is going to always make a product 5.5. It may take more or even less.
I provided a problem solving chart for reference. In a future post I will explain how to make the buffering solutions.
*This is better to look at on a computer!*
General recap: We need to know the pH of our products to fit the needs of our product. It is simple but important to find the pH of our products. Certain ingredients require certain pH levels, and we must accommodate that in our formulations. We need to remember the pH of the area to which we are applying it to ensure that it is not going to be problematic.
I hope you enjoyed this post as much as I have created it. Stay tuned for the next post.
The next post will be about Sanitation and Safety.
Work Cited:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4158629/
https://www.ncbi.nlm.nih.gov/pubmed/7469869
https://en.wikipedia.org/wiki/Aqueous_solution
https://www.google.com/search?q=ph+chart&rlz=1C1CHBF_enUS724US724&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjMmZ3sk63fAhVFX60KHaKtDY0Q_AUIDigB&biw=1517&bih=695#imgrc=CBjguhoVUz2giM:
https://www.omega.com/techref/pdf/introduction-to-ph.pdf
