In any cleaning process involving water, the surface tension of water must be reduced so the water can spread out, wet, and soak into a surface. Surface tension is what causes water to bead up. You can see surface tension at work by doing a little experiment. Place a drop of water onto a piece of waxed paper and notice how the drop will hold its shape and will not spread. You can even play a game and push the little drops together--they will join to make bigger drops. Now add a bit of soap to your water and place a drop of the soapy water on the waxed paper—it will no longer hold its shape. When teaching about surface tension, I had a contest with my students to see if any of them could put more drops of water on the head of a penny than I could. I put a few drops of soap in their water—and guess who always won? It was a great teaching tool because it demonstrated how soap reduces surface tension. Many of them went home and challenged their parents!
Substances that decrease surface tension are called surface-active agents or surfactants. Soap is a natural surfactant. Basically, any surfactant that is not a soap is a detergent. You hair and scalp get clean because surfactants decrease the surface tension of water and allow the water to mix with the dirt and grease (sebum) so it can be washed away.
For years people used soap to wash their hair, dishes, clothes, etc. Around the beginning of the twentieth century, household detergents became available. It is believed that the first synthetic detergents were developed by the Germans in the First World War period, due to a shortage of fat needed in the soapmaking process.
But why did people switch from natural soap to synthetic detergent? Soaps and detergents behave differently in hard water. Soaps can form a scum in hard water that will not rinse away easily. Detergents react less to the minerals in hard water. Plus synthetic detergents were much cheaper than soap.
WHAT IS HARD WATER?
Many incorrectly believe that only “well water” is hard water. However, according to the U.S. Geological Survey, it is estimated that more than 85% of the water used by consumers in the US can be classified at some level of “hard” water.
Rainwater is soft and mineral free. But, when it falls to the ground it seeps through the soil and rocks and dissolves minerals which give it its character. If the rainwater water passes through hard rock, it remains soft. However, if the ground water seeps through softer rocks, like the limestone very common in the Great Lakes Basin, it dissolves lots of minerals, principally calcium and magnesium, along the way. The degree of hardness becomes greater as the calcium and magnesium content increases. The term “hard water” was originally coined to refer to water that was difficult or hard to work with. Hard water requires much more soap, shampoo, or detergent than soft water; and the minerals in hard water can decrease soap’s lathering capabilities.
What does this have to do with hair?
You need water to shampoo your hair and hard water makes it harder to wash your hair. Each hair shaft is made up of little scales, like shingles on a roof. Hard water tends to make the scales stand up, which makes your hair feel rough and tangly. Since your hair is tangled and rough, it is more difficult to rinse out all of the soap. Soap is less effective in very hard water because its reacts with the excess minerals to form calcium or magnesium salts. These are not easily soluble in water and can result in soap film. Washing hair in soft water will have a different result because it leaves fewer insoluble deposits on the hair.
In commercial shampoos, natural soap has been replaced by synthetic surfactants.
What's the difference between a synthetic surfactant and natural soap?
Soaps are biodegradable products produced from natural, renewable resources like olive, palm, or coconut oils.
Synthetic surfactants, like Sodium Lauryl Sulphate (SLS), Sodium Laureth Sulphate (SLES), Ammonium Lauryl Sulphate (ALS), and others, are made from petrochemicals and created in a chemical factory. Although these synthetic surfactants do not react with hard water minerals as much, they do not produce the lather that consumers like. The lather comes from the addition of synthetic lather or foam boosters--like cocamide monoethanolamine. So, these detergent shampoos lather well in all types of water and rinse off easily and completely.
That's their only good point. Sadly detergent is very harsh, and damages your hair. It cleans out dirt and strips out the oil, including the natural oil that makes your hair shiny and strong. Conditioner was introduced as people noticed that detergent shampoo took all of the oils out of their hair and left it feeling dry and brittle. The oils your hair needs to be healthy come naturally from your scalp. Conditioner simply puts artificial oils in your hair so that you do not notice the damage done by your detergent shampoo. Natural soap is better for washing hair, because it does not strip the oils that are naturally in hair. Commercial shampoo is detergent. Detergents are really excellent cleaners (for dishes, laundry, and garage floors)!
WHAT CAN WE DO?
Shampoo manufacturers love to spread misinformation claiming that soap is "harsh." But, the problem with using a natural soap shampoo is often in the water, not the soap.
The first step is determining the hardness of your water. The map below provides some general information for those living in the US. If you are served by a municipal water company, call the city offices or the Superintendent of Water and ask for the test results. Another way is to call for a free hard water test kit from the makers of Diamond Crystal water softening products. Consumers can call (800) 428-4244 for the free kit, which includes an easy-to-use test strip, a coupon for a free bag of water softening salt, and other helpful information.
If your water is not too hard, just use your all natural soap shampoo and a bit of conditioner. The conditioner will help the scales on your hair lie flat, and allow the last of the soap to rinse out. You might have to experiment with different soaps and conditioners.
If your water is very hard you can use a weak acid rinse, like vinegar or lemon juice. The acid makes the scales lie down flat, and again allows the soap to be rinsed more easily. Please read our information on Natural Vinegar Rinses.
I believe I found another way for those of your customers with hard water that cannot afford a water softener and is something better than the vinegar rinse. I had bought some samples of your shampoo bars. I was very sad to realize that my water is hard as hard can be here. I was looking for water softeners but they are too rich for my blood and tried your vinegar rinse solution but it just didn't work for me. I was starting to get really depressed about it, so I decided to think just what was the problem. I decided to try regular filtered water instead, since filtered water takes away all that stuff that makes it unsafe for drinking. So, I filled up some bottles with filtered water and took a shower with that. It WORKED! It rinsed all of the soap from my hair and my hair was left feeling very soft. I got online right away and found shower head filters that cost much much less than a water softener. Jessica