What is a shampoo bar? What's their purpose?
A shampoo bar is typically hand made soap bars that are created to cleanse the hair as a replacement for sulfate based shampoos. In recent years using shampoo bars instead of sulfate based shampoos has increased as consumers have moved toward more natural ways of caring for their hair.
Shampoo bars work similar to shampoos in it's cleansing capabilities the difference is the way they are made and the different ingredients used to make the lather. In traditional shampoos, sulfates are the chosen surfactant used to increase lather, cleanse the hair, and lift the hair shaft to prepare the hair to absorb the conditioner (hence the higher pH to open the hair shaft). The process for making shampoo bar soaps is different.
Ingredients/How are they made?
Shampoo bars are made using by mixing sodium hydroxide (lye) with triglycerides (oils and fats) together with water to form the process known as saponification. During saponification the lye and water mixture reacts with the oils/fats to form soap and glycerin (glycerin is a by-product of saponification). You may ask what happens to the lye during this process? The lye "disappears" during the chemical reaction and the curing process - will discuss that later- allows time for the pH to lower and the burning effect of lye to diminish. The oils in the chemical reaction lend the softening effect to the soap. Side note, the more oils used the milder the soap. Any oil can be used to make shampoo bars, but the main oils used are coconut oil, palm oil, and olive oil. Since they typically produce the best lather.
Most soap makers us the cold press method in which the bars are allowed to cure once the chemical reaction is complete. Curing is simply the process of letting the bars sit for a while before use to allow the saponification process to finish. As the bars cure the water evaporates and the bars become milder, harder, and the lather increases.
Pros of Shampoo Bar
- High oil content can be useful for it's emollient (softening) properties
- Can be mild compared to some sulfate based products depending on how they're made
- For hair/skin that is already dry it can help replace oils removed by the cleansing process
- Glycerin can remain and be very moisturizing for hair and skin
Cons Of Shampoo Bars
- High pH level (normally 8-10) which can lead to dry, tangled hair (depending on oils used and how it's made). This pH disruption can cause breakage, contribute to frizzy hair, and reduce the natural gloss of hair
- If used in hard water (calcium, magnesium, or iron deposits) it can leave a film on hair that needs to be removed using harsh cleansing methods
- Can leave the hair "squeaky" clean or feeling stripped. That feeling is really the film deposit that has been left behind on your hair which can also lead to tangled, dry hair
- High pH level can cause dry, itch scalp
If you have any questions, comments, experiences with shampoo bars please share.