Neutralizing your soap
If you want to be truly successful making and formulating liquid soap you really need to consider purchasing a digital PH meter. I bought one from a fish supply store and it cost $80.00. You might find one cheaper on Ebay or Craig’s List but I highly recommend getting one. You really can’t successfully and accurately neutralize your liquid soap if you can’t accurately determine the PH.
I like my liquid soap to be between 8.7 and 9.7. I shoot for 9. There are several factors that will determine your resulting PH including oils used, lye excess amount, water evaporation during the cooking and water added for dilution. So even though you use the same recipe each time; it’s still helpful to meter each batch so you know exactly where you are at.
Just for example…Dr Bronner’s soap meters at about 8.5. They use citric acid in theirs. If you get a meter, take the time to test liquid soap you might run across. Real liquid soap not syndets!
I’m going to discuss two neutralizers because they are the only two I’ve used. I have not used boric acid but I understand that is similar to using citric acid as far as amounts go. But I have not used it.
Borax – Borax is actually more of a buffer and not really a “neutralizer”. It brings down the PH of liquid soap because it has a lower PH itself. Borax is also great because it helps thicken your soap, it softens hard water and helps prevent congealing (that layer of soap on top).
Even though borax is magical in liquid soap there is some controversy in using it. Some people claim it is not good to use on broken skin, children under three or sensitive skin as it can be an irritant. You’ll just need to do your research and find out if you want to use it. I have a couple of different types of liquid soap I make. One of them is thicker and uses borax and the other is a bit thinner and uses citric acid.
Citric Acid – Citric acid is a great neutralizer and easy to use. I haven’t heard of it being an irritant like borax.
You’ll need to determine the resulting PH of your soap. For this recipe using an 8% lye excess I usually meter around 9.5-9.7 PH. Heat your soap back up.
To buffer using a borax solution –
Even though I do a 8% lye excess instead of Failor’s 10%, I follow Failor’s recommendations for using borax. I make a 33% solution of borax/water and add 3/4 oz per pound of paste to my diluted soap. So I’ll boil 9 oz of water and add 3 oz of borax. You have to boil it while dissolving…it’s a sucker to get dissolved at times. It will turn to clear when ready. Since we ended up with 55 ounces of paste I’m going to add about 2.5 ounces (by weight) of this solution. Test your PH. If you want to drop it a bit more, you can add another .25-.5 ounce of the solution. If you add too much your soap will cloud up a bit. Now you can add your superfat ingredients.
To drop the PH using citric acid -
I use about 5 grams citric acid per 50 oz of paste. I weigh the citric acid in a Pyrex measuring cup and pour about 1-2 ounces of boiling water over it to dissolve. Add this to your warm soap mixture. When you add it, your mixture will look like egg drop soup. This is the result of the citric acid turning the soap it touches back into free oils. I then add my superfat ingredients and let sit over night. By the next morning the curdled soap has mixed back in and all is well. If it hasn’t… gently heat, stir and let it sit for a couple more hours. Test the PH. With this recipe it drops by about .3. So if I started at 9.5 it results in a PH of 9.2. If your soap started at a 9.7 then dissolve 10 grams and add that.
You’ll really just have to experiment and keep testing the PH. I’m happy with a 9.2.
You don’t want to add too much of the citric acid or your oils/fats will start separating out and you’ll end up with an absolute mess!
Superfating your soap
Once you’ve neutralized your soap you can stop there…or you might choose to add some superfat ingredients. There are two that I use:
Sulfated Castor Oil – Also known as Turkey Red Oil, Sulfated Castor oil is water soluble. If you were to add olive or avocado oil to your liquid soap it would simply float at the top. Sulfated Castor oil will mix into your liquid soap. I add it at 1% of diluted soap.
The only problem is that some people are allergic to sulfated products so they can’t use it. I use it in my main recipe along with borax and use only glycerin in my other recipe that I use citric acid in.
Glycerin – Glycerin makes a great superfat for liquid soap. It is a solvent (adds clarity) and provided emollient properties to your finished product. I add it at 1% of diluted soap.
For this recipe, let’s use 1% of each for our superfat.
We’ll discuss storing, fragrance, color and packaging next.