So, what's the difference between soap and detergent?

American consumers often use the words “soap” and “detergent” interchangeably, but in reality there are significant differences between these two types of cleaners.

A Quick History 

Soap is the original method (well, water and scrubbing were the original method) of getting things clean but the substance we call soap existed during Roman times and eventually became an established craft with centers in France, Spain and Italy. In the 18th century in Europe and the U.S., widespread advertising campaigns touted the relationship between good personal hygiene and health.

Detergents entered the picture about 1916 during World War I. A shortage of soap ingredients encouraged manufacturers to develop synthetic cleaners to meet demand. By the 1950's detergents had overtaken traditional soap products in homes across America. Today, detergents are used for laundering, dishwashing and many other types of cleaning.

 

The Chemistry

Soaps are made from natural ingredients, such as plant oils (coconut, vegetable, palm, pine) or acids derived from animal fat through a process called Saponification. Saponification is at the heart of soap-making. It is the chemical reaction in which the building blocks of fats and oils (triglycerides) react with lye to form soap. Saponification literally means "turning into soap" from the root word, sapo, which is Latin for soap. The products of the saponification reaction are glycerin and soap. Chemically, soap is a fatty acid salt.

 

Detergents, on the other hand, are synthetic, man-made derivatives. While soap is limited in its composition, detergents can be formulated to include other ingredients for all sorts of cleaning purposes. Perhaps the most common and versatile of these ingredients are surfactants … surface active agents.

 

 

About Surfactants

Surfactants aid in cleaning because they reduce surface tension and improve water’s ability to spread evenly over it. This creates a more uniform wetness that makes dirt and soil easier to wipe away and remove. Surfactant molecules can also have either a positive or negative charge, with one end attracted to water and the other end attracted to dirt and grease. This helps detergents attach to dirt, break it up and let water wash it away. A commom surfactant that you may have heard of is Sodium Laureth Sulfate (SLS).

 

 

Behavior in Water

Most cleaning products today are detergents. One of the biggest reasons for this is the way soap reacts with water. While detergents are free-rinsing (meaning they don’t leave a residue), soap needs a clear water wash after application or it will leave a film. In hard water, soaps form scum. Soap scum affects more than just cleanliness; it can deteriorate fabrics and eventually ruin clothing or other surfaces. Conversely, detergents can work in any level of water hardness since they react less to the many minerals in hard water. Finally, soaps need warm water to work at all. Detergents, on the other hand, can be built to perform well in any water temperature. This versatility enables detergents to be used in everything from shampoo to laundry liquid to hand cleansers and stain removers.

Detergents in Commercial Cleaning

Because of their versatility in formulation, detergents are used almost exclusively today in commercial, industrial and facility cleaning. Detergents can be built to suit specific cleaning tasks – laundry, degreasing, carpet care, or floor cleaning, for example. They can be formulated as acidic, alkaline or pH neutral, and ingredients such as enzymes can be added to aid in these specific applications.

As a side note, a number of commercial hand care products still have the word “soap” in their name, even though they are really detergents. 

Earthly Crush Products

Our 'Dish Soap in a Ball' is a combinations of traditional soap, detergents, and natural alkaline powders. We find combining forces is an excellent cleaning solution.  

Our 'Shampoo Pearls' contain no Soap as we want it to rinse cleaning out of our hair. We use a detergent with added surfactants, plus natuaral oils to gently cleanse and condition the hair.