Talking Soap
Where to begin..., let's see...The difference between soap and detergent:
A few years ago, I was helping the team from Newton (a children's science program here in Norway) create a segment about soap. see program here (in Norwegian) (the giant soap volcano in her nightmare sequence was made by yours-truly. That sucker deserves its own blog entry.) The first thing I talked to them on the phone about was how people confuse soap and detergent. They actually chose to lead with that in their segment, so I'll start with that here as well.
Soap is the combination of fats + base solution and has been around for over 2000 years. Detergents were invented in the 1940's using petrochemicals.
There is some debate, myths and legends about how soap was first discovered. I imagine that soap's origin story goes something like this: Melted animal fat falls into ashes from fire, ashes are used to clean something and someone notices that the animal fat + ashes clean better than just ashes and water. Why? Well, we know now, but they didn't know then, that wood ash, especially wood ash from hard woods, contains potassium and when it is mixed or drained through with water, it becomes a potassium hydroxide solution, or KOH. A solution of KOH, made crudely with wood ash, combined with any kind of animal fat will make a pasty, muddy looking soap. Why? Because KOH is a mean bully and it pulls apart fat, eats it, rearranges it until it is a type of salt and not a fat. It becomes potassium tallowate and water and glycerine (we'll talk about glycerine and why it is there another time) and probably loads of dirt from the ash because nothing has been measured or cleaned or filtered nicely. The year is sometime BC and soap is discovered. *cue hero music.
To make soap, they were creating a base solution, and that is 'base' as in the pH scale, not bass in the music scale. Base is the opposite of acid. (I'll write more about pH another time, too.) The solution is strong enough to eat through clothing and a layer or two of skin. Ouch. Once it is mixed with enough oils and fats, it becomes soap and there is no more caustic base left. Ensuring there was enough fats for the KOH to bully and eat was important. They didn't want any of the caustic chemicals left over and sitting alone because then it became a very harsh batch of soap. The soap makers learned to put a small, cooled piece of soap to their tongue. If they felt a sting, they knew they had to add more oils. Some soap makers still check their batches like this.
KOH is the base chemical used to make a true liquid soap, even today. Of course, today, we have better sources of it than leeching it through wood ash. Today, we measure our chemicals by the gram, mix carefully and cook patiently. I don't make liquid soap, but I know a lady who does and she does it brilliantly. Her name is Agneta and she has been a fellow soapmaker of mine since I began, 6 years ago, generously sharing her time and experience with me over the internet. You can see her work here: Tvålmakaren, Sweden
So, next time you are looking for liquid soap at the store, check the list of ingredients. If they don't include potassium something-ate it isn't soap. (btw, I will have some of Agneta's soap in Pryd in the near future, if you are reading this in the Trondheim area.)
Another strong base chemical is used to make harder bars of soap. Sodium hydroxide, or NaOH, or more commonly known as lye. Lye is sometimes also used as the term for KOH, so that gets a bit confusing. I like to stick with their chemical abbreviations, then there are no misunderstandings. NaOH does the same thing KOH does, so on the ingredients list of a real soap, you should see, Sodium something-ate. Because the NaOH eats the oils and turns them into soap, water and glycerine. The 'something' always refers to the type of fat or oil used in the formula.
Some soap makers simply list the oils, but if you are looking on commercially made bars, you will see what are called the 'INCI' chemical names. 'INCI' stands for the International Nomenclature of Cosmetic Ingredients. (AAG, which stands for Acronyms Are Great.) INCI is a list of agreed upon names that manufacturers put on labels so that there is a standard of some sort. The words need to transcend languages in some ways but there are variations, with the Americans usually being the exceptions. (no real surprise there.) For example, in the US, soap isn't considered a cosmetic, so legally, it only has to be labelled 'Soap'. Everywhere else I know of, the ingredients need to adhere to INCI standards for that region and language. Cosmetic manufacture laws are long and boring and a bit confusing. If anyone wants to read about them, I can give you links. I am an ingredients list reader because of sensitivities to certain chemicals, so rely on truthful information and claims on packaging, but again... another topic for another blog entry, because now, I'm tired.
Thanks for reading. I hope you found it informative and interesting. I touched on a few topics in addition to the one I set out with, perhaps raised some questions, so feel free to write in the comments section below. *bangs on the mic* Is this thing on?
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| soap molecules forming. neat, eh? |
