Soap - Why We Need It!
Soap, it has been in my life since I was a baby. It is something I use everyday and sometimes take it for granted. But do we really know how soap came to be such an important part of our lives and why even to this day we love to have soaps that do more than just 'clean'?
The precise history of how soap was developed has been lost. But what we do know is that ancient Babylonians were the first to use a cleansing agent. They have mentioned cleaning themselves with a mixture of water, alkali, and cassia oil as far back as 2,800 BC.
But don’t imagine for a minute that these were nice aromatic bars that produced lather and killed germs in a jiffy. It was more of a slurry, kind of like our modern day liquid soap. Still, that was better than nothing at all. All good things start with baby steps and so did soap-making.
The next mention of soap is by Egyptians (circa 1,500 BC) in a scroll known as Ebers papyrus. They mixed animal and vegetable fats with alkaline salts and used the blend for washing. Early forms of soap, were a mixture of abrasive elements such as clay mixed with fat and metal salts, and were used by every ancient civilization. With trade and commerce, crude soap must have made its way to India and the Far East.
By the second century, rough soap made from tallow was quite common in Rome. The physician Galen mentioned it as a medication for skin sores.
Modern soap was first made in the Middle East. We find a formula in the 9th-century narrative by scientist and alchemist Muhammad ibn Zakariya al-Razi.
Soap was a major export of Syria at one time. Aleppo, the city that was devastated by the recent civil war, was well known for its aromatic soap made from olive oil, in the fifth century. During the middle ages, over in Europe, soap was first produced in Marseilles. Over in England, soap factories sprouted up at Bristol and at Cheapside, near London.
Until the Industrial Revolution and accompanying advances in chemistry, soap making was an artisanal practice. It was difficult to extract alkalis. The final product was crude and barely sufficient. It might have smelled nice, but the efficacy is doubtful.
Three advances at end of the 18th century led to modern soap making:
- In 1780, James Keir made alkali from sulfates of potash and soda. This introduced soft soaps that were smooth and could be shaped to fit inside the palm.
- After a few years, Nicolas Leblanc pioneered the manufacture of alkali from common salt. This brought down the price significantly since salt is a commonly available raw material.
- In 1807 Andrew Pears produced the first high-quality transparent soap. The Pears Bar made from natural oils and glycerin with the delicate smell of rosemary and thyme is available to this day.
How Does Soap Work?
Soaps and detergents play a crucial role in everyday life.
We are exposed daily to several pathogens, this includes bacteria and viruses. This results in the need to clean ourselves and our clothes. Whenever you sit on a café stool, walk your dogs in the field or grab a railing on the subway, you are picking up germs.
To clean ourselves and to protect our health, soap and detergents are the first line-of-defense. But how is modern soap made?
To know that, let’s talk of water’s surface tension. Each water molecule attracts another. That is why water molecules form a perfect teardrop shape without breaking away. If only this tight bond could be shattered, water could clean better. To reduce the surface tension of water, we need surfactants. In essence, it makes water spread more effectively through a medium such as cloth or skin.
Soap is the most commonly used surfactant. It is made from treating fatty acids with alkali. The fatty acid might be from a plant or animal source. Common examples include degenerated cooking oil (where do you suppose all that used oil goes from restaurants?), olive oil, palm oil, and so on.
The alkali is NaOH (sodium hydroxide or lye) or KOH (caustic potash) both reasonably inexpensive to produce in bulk. The fat is boiled and split into fatty acids. Thereafter, it is treated with NaOH or KOH. The former makes a soap that is harder and refuses to lather quickly. Most soaps contain a mix of both to control the softness.
The soap works by reducing surface tension so water can penetrate quickly. It is also a hydrophilic chemical and attracts oily molecules (such as grease on a shirt) towards itself. It is interesting to note that hard water (water with dissolved magnesium and calcium salts) does not lather well and therefore cleans imperfectly. The cleaning action by soap is best done using soft water.
Types of Soap in Use
Though the chemical formula of soap is basically the same throughout all its avatars the form, texture, and action are vastly different.
Pears was the first brand to market this variety. It uses a bit of alcohol in the mix to give the product a see-through texture.
A literal lifesaver. Liquid soap stopped us from slipping on a wet bar of soap and spending a couple of months in bed. The addition of potassium salts makes the soap soft, mushy, and bubbly. Our only concern, from an environmental outlook, is that a majority of liquid soaps are packaged in plastic containers and would recommend something stored in glass containers or compostable packaging.
Laundry Soap and Detergents
They have the same chemical principle but are a little different in composition. Detergents are made from harsh chemicals unsuitable for skin application. Half of the mass is what is known as sequestering agents. These act on hard water to separate the dissolved salts. Sodium carbonate, sodium silicate, sodium phosphates are the most common builders. They also contain industrial enzymes to dissolve oils, bleach to remove stains, and optical brighteners. Though there are competing claims, Tide, created in 1943, is widely accepted as the first surfactant-builder composition. Detergents are available both as powder and liquid. Front-loading washing machines use less water and need special low suds formula.
Soap is an ideal way to apply various skin medications. Medicated soaps contain clotrimazole, ketoconazole, and a variety of other antifungals that treat skin infections, scabies, and itching. Soaps for acne contain soothing additives that do not cause a flare-up of the condition.
A herbal soap may contain tea tree oil, aloe vera, turmeric, and many other supplements that keep skin smooth and supple.
As we learned during the pandemic, handwashing with soap is vital. Soaps can kill bacteria and viruses very efficiently. Soap molecules literally pry pathogens apart.
Next time you take a bath, remember the five millennia-long history that precedes the simple act of lathering yourself and taking a hot shower.