A Sudsy Story
Soap has been around for a very long time, one of the first documented references of its use is inscribed on clay tablets dating back to 2500 B.C. belonging to the Sumerian people of Mesopotamia; found near the Euphrates and Tigris rivers.
Another record is the Ebers Papyrus, an Egyptian medical text from around 1500 B.C.where it states that people would combine oils and fats with alkaline salt to create a cleansing product.
The Roman Scholar Pliny the Elder (23 A.D. — 79 A.D.) records in one of his volumes from the first known set of encyclopedias that the Phoenicians would combine Goat fat and woodash to be used to clean the body or clothing. Pliny also mentioned the Gauls in Germany preparing similar products.
In 300 B.C., the Romans combined olive oil and sand to be used as an exfoliant, which would be scraped off with a smooth edged tool called a Strigil leaving the skin smooth and clean, it is believed this was adapted from the Greek culture often following with the treatment of herbal salves. The Roman city of Pompeii which was destroyed in the eruption of mount Vesuvius in 79 A.D. was home to a commercial soap manufacturer.
The legend of the discovery of soap was most likely taken from the imagination of the Roman’s to debunk the Celtic people’s claim, however the story goes that a woman was washing her clothes along the Tiber river at the base of Sapo hill (A fictitious mountain), downstream from several sacrificial fires. The woman noticed that the clothing got much cleaner with less effort at the particular spot near the river. It was due to the melting fat from the fires combining with the ash from natural fuels (Wood and plant material) leaching into the river downhill with runoff rainwater. The chemical reaction that occurs in making soap is known as Saponification, named after the legend.
Around 700 A.D. the trade of soap and the raw materials needed to produce it had flourished with the help of the Italian and Spaniards. Small production took place all over such as in Netherlands where the primary ingredient used was fish oil versus the common tallow in Northern Europe and the finer oils and additives used in the best quality soap production in Southern Europe.
At the time of the Black Death in medieval Europe many public baths were closed due to the belief that it aided in the transmission of the plague (although bathing in general would have aided in preventing infection). An estimated 30%-60% of Europe’s entire population was killed by the epidemic.
During the Renaissance the production of perfumes soared and the majority of soap was used in the cleaning of clothes and not body washing. At the time people opted to cover up the body odor with heavy scented perfumes rather than cleaning themselves.
In the 1600’s people became more aware to the fact that using soap for personal hygiene prevented illness, infection and disease, leading Soap to become an integral part of America’s
Soap’s cleaning power is effective in many ways in regards to hygiene. It acts as a bridge between water insoluble properties such as oil and grease (non polar hydrocarbons) to wash off with water (Polar molecules), due to the fact that the soap has both polar and nonpolar properties. The soap allows water to surround the oil molecules and wash away freely.
Soap has surfactant properties to it which allows it to suspend dirt and particles within it, then being washed away with water. Studies have shown that the simple act of washing your hands before and after doing certain tasks like using the restroom and before eating can cut the chances getting a harmful bacterial or viral infection by up to 60%. With the now common addition of antimicrobial properties to hand soaps any harmful bacteria that is not washed away is effectively killed. The same antimicrobial agents such as Triclosan and chloroxylenol are used in hospitals and consumer products alike.
It has been proven that no amount of hand soap will effectively cleanse your hands if the method of washing is not correct, those people who just rinse their hands under the tap before leaving the bathroom, I’m talking to you. It bothers me that with the additions of motion activated hand sinks in public restrooms, the water temperature is not set for the job of washing your hands. For the most effective clean it should be as hot as you can comfortably stand.
Having had worked in the food industry for some time the health departments guidelines for hand washing are quite a bit more relaxed then those of surgeons, which is okay since hands are not literally reaching inside of the customer. Either way, I will go over both techniques briefly.
For food safety and public health the proper method is to get the water as hot as you can stand and rinse the hands before starting with soap, you should then scrub with soap for twenty seconds getting the palms, back of the hands, in between finger, under nails and around the wrists before rinsing thoroughly and reaching for a clean, single use paper towel. Remember if you have to touch the faucet to use the paper towel to act as a barrier and not recontaminate the hands.
The surgical scrub in method is much more complex and for my sake and yours I really hope they don’t cut corners.Their method is timed for five minutes, where they rinse with hot water before scrubbing with antibacterial soap all the way up to the elbows and everywhere in between. They clean under the nails with a scraper and make sure the hands are above the elbows at all times to eliminate the possibility of bacteria running off down to the hands. When the time limit is met for scrubbing they are to pass their hands and arms under the hot water going in only one direction, one at a time to prevent cross contamination. They then dry off with a sterile towel and finish the scrub in process.
Now that we’ve covered history, some chemistry and application lets dive into how to make it. I first took an interest to soap after seeing Fight Club, if you’ve seen the film you know what I’m talking about and it is badass. Tyler Durden from what I can tell is using the Hot process method of making soap. Now there are three ways to make soap from scratch, cold process, warm process and hot process (also known as Kettle or Pot process)
Lets look at the ingredients of basic soap first, Fat and (or) oil is the base of the product. Sodium Hydroxide (Lye) is the acid. When the lye solution is mixed with the fats, the process of saponification occurs where a salt (the cleaning agent) is created.
Hot process is the most time efficient method as the final product does not need to cure like the other ways. Hot process includes heating the water and lye (caustic agent) with the fat to the point that the saponification process occurs. When it is homogenous and begins to thicken that is the point where fragrance and color are added. Setting will occur quickly and it can be used immediately, since the process eliminates the caustic effect of the Lye.
The warm process involves incubating the mixture of lye solution and fats for several hours at warm temperatures around 160 degrees Fahrenheit. The caustic reaction occurs more slowly and it needs about 48 hours to harden and cure.
The Cold process is the classic and most widely used method, it is much like the hot process method but without the addition of heat. Thus the process of saponification takes much longer to complete, needing four to six weeks to properly cure. If the chemical reaction is not completely finished or failed to properly occur, active Lye can still be present causing the product to irritate or burn the skin. That is why it is important to test the acidity content with either pH test strips or the less definitive tongue and touch methods. With the tongue method the soap maker touches the tip of the tongue to the finished product and if it irritates or burns it is not suitable for immediate use.
There are other methods of soap making such as rebatching and melt & pour, but those are the lazy ways and contain none of the fun and exciting chemistry. If anyone ever happens to try their hand at the craft of soap making, make sure to get the measurements right with the proper ratios of acid to base, and with all of the methods take safety precautions and keep vinegar nearby to neutralize the Lye if it gets in contact with wet skin. Fun fact never add sugar to a lye solution as it produces carbon monoxide.
In conclusion of this fascinating piece of literature soap has been ingrained within society for thousands of years and it plays a very important role in the prevention of illness and infection. I find it interesting and useful to know how things we encounter in our everyday life work and came to be.