The History of Soap

Why Use Soap?

Why do we use soap to wash our hands?

With hand-washing coming under the public lens more than ever, the importance of soap in staying healthy and safe has been brought to the forefront of public conversation. How-to's and doctors warnings are abound; Use soap. Warm water. Wash for 20 seconds. But while bent over the sink, rubbing your hands, counting the seconds away and staring at yourself in the mirror, have you ever wondered: why is soap so important? What, exactly, does it do? Why isn’t just water enough?

Your parents taught you to wash your hands. Their parents taught them. But why? What would happen if you never used soap? Sure, your hands would be dirty. But without getting aggressively philosophical here, ask yourself, what is dirty?

Soap is a Unique Molecule

Well, in this case, dirt or grime refers to oil or grease. Water will get rid of a majority of loose dirt particles, but what remains is the fats. The lipids. Let’s say you’re cooking: you can hold your hands under a running tap, and maybe the food stuffs break apart, fall away. In their wake remains the oil, the grease, the lipids -- clinging to your skin, refusing to be washed away by water alone. This is because the lipids that compose grease and oils are hydrophobic, or resistant to water. They automatically refuse to bond with water, leaving them insoluble and unable to dissolve. If you’ve ever seen the way oil clumps together in curries or sauces, you’ve seen this hydrophobia in action.

The unique property of soap is that it can dissolve in both oil and water because its molecule is simultaneously hydrophobic and hydrophilic — meaning certain parts of the molecule can dissolve into water. This is the magic of how soap works. Hydrophobic ends of the soap molecule bond with grease and oil, and then, to escape the water, turn inwards. This wraps the hydrophobic lipid in a hydrophilic shell, creating a water-soluble “briefcase” that let you smuggle the unwanted grease particles off your hands and down the drain.

Scientists and health experts encourage you to wash your hands using warm water because the heat helps soften the lipid molecule, making it easier to bind to the soap.

Soap is Better than Rubbing Alcohol and Hand Sanitizer

Soap in its basic form is useful for more than just ridding your hands of grease and oil. Viruses, including the novel Coronavirus, and many types of harmful bacteria, are coated in a lipid membrane. In the case of viruses, this membrane is studded with sharp prongs that help the virus cling to host cells and penetrate them. The pointed, hydrophilic ends of the soap molecule bind with the lipid barrier of the virus and force it open, ripping the virus apart.

Hand Sanitizer should certainly be used when you don't have access to a sink, but still leaves you vulnerable to viruses and other pathogens. Some viruses are not enveloped in the same lipid barrier that alcohol can penetrate and destroy, and sanitizer leaves your hands wet -- making it easier to scoop up unwanted molecules from the environment. Beyond that, the mechanical action of hand-washing is almost as important as the soap itself. By rubbing your hands together, you're doing more than lathering -- you're creating friction that helps break down those harmful molecules. And by drying your hands with a clean towel, you're reducing your chances of picking up unwanted molecules on public surfaces.



The First Soaps

The earliest evidence of soap making dates all the way back to 2800 B.C in ancient Babylon. There exist tablets, over four thousand years old, describing different methods and recipes for soaps. One, dating back to 2200 B.C, explains how to make soap out of water, alkali, and cassia oil. Historians speculate these soaps were originally created towash wool and textiles, rather than skin, but may have eventually developed to be used by priests as a method of ritualistic purification.

According to legend, the Romans may have discovered soap in the wake of an animal sacrifice at a fire pit atop a Mount Sapo, from which the Latin name for soap, sapo, is said to be derived. Supposedly, women downriver found that clothing lathered better in the tallow-laden stream, leading to the discovery of soap. This is probably false, however. There is no record of any Mount Sapo, nor evidence that the Romans ever burned animals as part of religious sacrifice. But never let the truth get in the way of a good story.

Surprisingly, despite the immense prominence of bathing in Greek and Roman culture, soap-use was more uncommon than one might have supposed. In fact, they didn’t use soap for bathing at all, but olive oil, spreading it over their skin then scraping off with a curving, blunt blade called a stigil.

Even stranger, the Romans may have even known about soap, but actually preferred their oil and stigil. Some of the earliest reports of soap come from the roman historian Pliny the Elder in his Historia Naturalis, in which he describes a waxy substance that he called sapo, made from tallow and ashes that the Gauls used to style their hair. This sapo however may not have undergone the saponification process required to create bona fide soap as we know it today, but would have been one step away from it.

The fall of the Roman Empire brought with it a decline in numerous hallmarks of civilization. Administrative practices, infrastructure development and maintenance, and social practices fell into decline — including bathing, which was in fact actively discouraged by the Church for its association with the previous regime. Bathing further fell out of fashion during the Black Plague when doctors began to theorize that bathing perhaps promoted the spread of disease, or “miasma” and that it would be prudent, in an effort to curb the pandemic, to bathe less frequently. We recommend against medieval medical advice.

While soap was still in its infancy in Europe, soap-making began to truly flourish in the middle east, where they began to experiment with vegetable fats rather than animal tallow. Many Middle Eastern soaps used salts that helped separate the glycerin, making harder, more solid soaps than their European counterparts. Down below we will discuss some of these soaps, and the immense impact they had on soap as we know it today.

Are Soap and Detergent the Same Thing?

Though similar, detergent and soap are not the same. Detergent is designed to be more water soluble, and bind with molecules commonly found in hard water, like calcium, to prevent the formation of soap scum. This is what makes them so excellent for usage in laundry and washing machines, where you're more likely to use hard water and have a machine to protect.

While the most basic of soaps could be created with raw ingredients you could literally find at a campfire, detergent requires more processing. Some precursors to detergents were created in China using the seeds of the Gleditsia sinensis plant, but true detergent as we know it today did not emerge until the 20th century.

After a shortage of animal oils during the first world war, German scientists discovered a way to create ‘saturated fatty alcohol’ which was used to create these first detergents. Funnily enough, you're probably using more detergents than you realize. Many of the hand washes, body bars, and shower gels are in fact not soap, but detergents, hence why the word soap is actually unfound on many of these products’ labels.



The Soaps that Changed Soap, Forever

Aleppo Soap

Predecessor to the famous Castile Soap and Godfather of many other fine, hard soaps, Aleppo Soap was a hot-process soap made with olive oil, lye, and most distinctly, laurel.

Said to have originated in the Levant region of what is today Syria, Jordan, Lebanon, Israel and Palestine. Factories in the Syrian city of Aleppo, from which its name is derived, began to mass-produce the soaps in huge vats set into the floor, heated by underground fires. The oil and lye would boil for three days, forming a layer of molten soap atop the mixture, laurel would be added (giving it its signature green color) and the mix then set on the factory floor to cool for a day. Once cooled and evened out, the soap was cut into cubes and placed in an underground chamber to set for up to a year. During this time, the soap would continue to dry out, remaining alkalis would break down, and the exterior would take on a golden-yellow sheen.

The impact that Aleppo Soap had on modern soap-making cannot be understated. Records suggest it may have been the very first hard soap of its kind, and is the very trunk of the hard-soap family tree from which all others are derived. In comparison to the softer, harsher, smellier soap precursors made with animal tallow, the Aleppo soap was fragrant, graceful, and soft on the skin. It was a pleasure to all of the senses, and as such exploded in popularity, making its way all across the world in a time before automobiles.

Castile Soap

Castile Soap is arguably the most famous of the early hard soaps. Pure white and with little to no scent, the Castile Soap was the stuff of only royalty and exceedingly rich merchants in medieval Europe. Made with a simple recipe of olive and lye, the soap is nearly identical to Aleppo soap save for the exclusion of laurel oil which was largely unavailable to the Castile soap makers.

Its similarity to Aleppo soap is no accident. It is said that many of the crusaders returning home from war in the Middle East brought with them bars of the famous Aleppo soap. These were probably the first truly ‘hard’ bars of soap seen in Europe and quickly became a coveted item for both their undeniable quality and rarity. Like the Aleppo Soap, Castile Soap came to be in an era where most soaps were revolting mixtures of wood ash and rendered animal fat. Compared to its European counterparts, which were dark and grimy, the Castile Soap's pure white color and near lack of scent made it seem like purity incarnate.

What sets Castile Soap apart from its predecessor, the Aleppo soap, were two components of the production process. First, the Castile Soap used an impure sodium carbonate from the ashes of the halophyte plant. Second, brine was added to the mix during the boiling process, causing the soap to rise to the surface of the cooking vat and allowing the soapmakers to scoop it out, leaving behind excess lye and other unwanted adulterants. This resulted in an extra pure, extra hard soap.

Nabulsi Soap

Another famous middle eastern soap comes from the Palestinian town of Nablus. The ‘Nabulsi’ soap is similar to Castile Soap, made from olive oil and lye and lacking Aleppo’s signature laurel oil. And, also Like Castile Soap, it is hard and ivory colored.

Nabulsi Soap took the Middle East by storm in the 14th century and branched outward, reportedly becoming a favorite of Queen Elizabeth I herself. Like Castile Soap, the main ingredient is virgin olive oil and water — what made this soap unique was its alkali: a sodium compound made by mixing the ashes of barilla plant and lime. The soap is stirred continuously for 8 days, growing increasingly concentrated, and then poured into a wooden frame to set. Once cooled, they are cubed and left to dry, stacked like evenly spaced bricks into tall, hollow columns that permit the passage of air. The Nabulsi Soaps are left to dry and mature for up to a year at a time.

Bristol Grey & Black

Historically, Europe’s had a real on-again, off-again relationship with bathing. The Romans brought with them their public bath houses and made their usage customary for the common folk. When the Church stepped in as the next administrative body, ushering in the Middle Ages, they clamped down on the bathhouses that had become hotspots for prostitution.

While hard soaps with pleasant, subtle fragrances had become ubiquitous in the Middle East, European soaps lagged behind well into the ninth century; while the ancient babylonians had figured out soap literal thousands of years beforehand, Europe’s soap remained the soft and unpleasant mixtures of wood ash and animal fats.

And even those soaps that we would today wrinkle our nose at didn’t come cheap to the average European worker. While the Castile soaps were obviously reserved for those with deeper coin-pouches, even the more rank and undesirable varieties of soap were considered expensive luxuries for your average peasant.

The most prominent region for British soap making was Bristol, where they made two types of soap. Bristol Gray Soap, which was said to be less expensive than Castile Soap but still generally out of reach of your average working man, and Bristol Black Soap, a cheaper, softer, smellier soap that some records suggest was more likely used for laundry rather than the skin. The Black Soap was said to be extremely harsh, so much so that unless clothes were washed thoroughly, could remain in the fibers and irritate the skin. It is likely that both of these soaps derive their name and color from the wood ash used as an alkali in the soap making.

Marseilles Soap

The Marseilles Soap was another hard-soap that can trace its origins through Castile Soap all the way back to Aleppo. What makes the Marseilles soap unique is the specific inclusion of water from the Mediterranean Sea with the traditional olive oil and alkali ash gathered from marine plants. In 1688, by royal decree of the Sun King Louis XIV, it was mandated that all Marseilles Soap be made with only olive oil — animal fats were completely forbidden, and transgressors of the law risked exile!

On an interesting side note, Louis XIV himself was said to be deathly afraid of bathing. So much so, that a Russian ambassador to France once remarked that the king, “stunk like a wild animal.” Legend says that his majesty only ever took three baths — in his entire life — and would have to open windows so his courtiers could stand in the same room as him.



What is Soap?

And there you have it! A short history of soap, and some the more outstanding turning points in soap making. It is through soap that we can trace the growth of civilization and experience small slivers of people and places lost to use through time. In an era where our shelves are lined with mass-produced soaps full of lab synthesized chemicals, it is important to remember what soap once was and what it still could be.

Soap was feeling. Soap was experience, purity, divinity. It was made by hands and watched with eyes. A soap maker's apprentice would walk along a riverside, gathering barilla plants for his master's lye. Another would stand over the vat, as was the tradition of their parents, and their parent's parents, stirring, watching. Knowing. Soap was tradition. Soap was life. It was made with what the land around you gave. What made you and your people unique made your soap unique. It was a reflection of culture, geography, time.

It is through these soaps that these people live on today.