Pod Insights Stuff You Missed in History Class A History of Soap About this episode All over the world, for all of human history – and probably going back to our earliest hominid ancestors – people have found ways to try to keep themselves clean. But how did soap come about?
Transcript Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.
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2:14 Holly Frey? Welcome to Stuff You Missed in History Class, a production of iHeart Radio.
2:24 Tracy V. Wilson? Hello and welcome to the podcast. I'm Tracy V. Wilson.
2:28 Holly Frey? And I'm Holly Frey.
2:29 Tracy V. Wilson? We got an email from listener Liz asking for an episode on the history of soap. That is something that I had on my list back when Holly and I first joined the show in 2013. Holly has thought about doing a soap episode also. It has never happened. It had never happened. So I was like, why not? Why not? Now that someone has actually asked for something that I thought maybe no one would find interesting, we will do it. We'll do it now. This turned out to be tricky to do the research on. Because Holly's laughing, a lot of writing about soap is either really hyper-specific,
3:13 Tracy V. Wilson? like the history of the soap industry in one particular city over a specific period, or it is so broad that it's hard to pull details out of. And then there are also some details that just get repeated all over the place, but they don't really add up. A lot of the books that are connected to this history are really histories of cleanliness or hygiene, which is a slightly different thing. So in parts of this episode, we're going to be talking about a bunch of things that all happened in roughly the same period of history, but not necessarily in a specific order chronologically.
3:59 Holly Frey? And now you know why I never got an episode about soap turned out.
4:03 Tracy V. Wilson? Yeah. When I asked you about it, you said, I think I ran into some kind of problem and I learned through experience what the problem was.
4:11 Holly Frey? Yeah. All over the world, for all of human history, and probably going back to our earliest hominid ancestors, people have found ways to try to keep themselves clean. Hygiene norms really vary from one society to another, but the existence of some kind of norm seems universal, or at least, pretty close to it. People have washed or bathed in springs and ponds and rivers. They have used sand, or pumice, or brushes, or corn cobs to scour the skin. They have applied oils to their bodies and then scraped it off with a blade or some other tool. Saunas, sweat lodges, and sweat houses go back thousands of years in multiple parts of the world.
4:54 Holly Frey? A lot of these practices combine cleanliness and hygiene with some kind of spiritual or religious ritual, and some of them also help build community.
5:04 Tracy V. Wilson? People have also used a lot of different plants as part of this, specifically plants that are high in saponins, which are naturally occurring molecules that foam in water. Saponins have a range of uses and effects, and some of the plants they are found in are edible. Although if you eat too much saponin, that can make your tummy hurt. High saponin plants include the genus Saponaria, or the soap warts, which are native to Asia and Europe, as well as the Sepindaceae, or the soap berries, which are native to tropical regions in most of the world.
5:45 Tracy V. Wilson? Multiple species of Soapweed Yucca and Soap Bark Tree are native to the Americas. Common Ivy, which is native to Europe and Western Asia, and Chinese Honey Locust, which is native to East Asia, are other examples of these plants that can produce this foamy kind of soapy substance.
6:07 Holly Frey? People around the world have used these and other high sapinin plants to make preparations to clean their skin and hair, to soothe and treat skin conditions and injuries, and to wash clothing and other items. These range from the simple, like boiling soap berries and then using the water to wash your hair, to the complex, like multi-step processes involving grinding, burning, steeping, and mixing with other substances. In some parts of the world, today's word for soap comes from the name for one of these traditional preparations or the plants use to make them. In others, the word for soap is just a local variant of soap or of the word for soap in another language.
6:50 Tracy V. Wilson? One step of the soap-making process is called "saponification," and the words "saponification" and "sapinin" both trace back to the Latin word for soap, which was "sapo."
7:05 Tracy V. Wilson? I'm just gonna say, one of the resources we've been using for pronunciation lookups has been down for more than a week, so I apologize if we say any of these things wrong. These plant preparations can produce a lather, and they help keep things clean, but they are not exactly the same thing as soap. Soap is a substance that's formed through a chemical reaction between alkalis and fats. So if somebody added soap berries to a fat like tallow, and they mixed that with an alkali like lye, that would be considered soap. But soap berries by themselves, steeped in water, would not.
7:46 Holly Frey? Since soap comes from the interaction between alkalis and fat, it seems reasonably likely that in the ancient past, people all around the world discovered a sort of proto-s soap as they cooked meat over a fire and the fat dripped into the ashes, or as they used ashes to scour pots that had been used to cook or store oils or fatty foods. But intentionally-made soap has a somewhat narrower early history, one that's focused primarily on Western Asia, Northern Africa, and Southern Europe, basically all around the shores of the Mediterranean Sea. At the same time, tracing the details even of this narrow history can be tricky.
8:29 Holly Frey? While there are ancient documents that have been translated with the word soap, it's not necessarily clear whether the original word referred to actual soap or to some other substance that was being used for cleaning.
8:42 Tracy V. Wilson? The earliest known written references to soap are probably found in Sumerian cuneiform tablets from southern Mesopotamia in what's now Iraq. These tablets date back about 4,500 years. A Time Magazine article from 2020 points specifically to a tablet describing the use of wet ashes to remove the lanolin from wool, saying that the ash would combine with the lanolin to make soap. Wet ashes are an alkali that would have helped remove the lanolin from the wool, but lanolin contains mostly waxy esters rather than the fats that are needed for
9:25 Tracy V. Wilson? saponification, so it does not seem like this process would have produced much actual soap. So many other articles just refer obliquely to Sumerian tablets as giving recipes for soap, but they don't go into detail about what the recipe actually says or which specific their tablet they are talking about. Trying to track down the details on this had me going in a bunch of very annoying circles.
9:56 Holly Frey? Another early written reference to soap dates back to the Babylonians, who also lived in ancient Mesopotamia. This reference is in the form of clay cylinders with an inscription that translates to "fats boiled with ashes." This suggests that the Babylonians were intentionally making soap and then storing it for later use.
10:18 Tracy V. Wilson? The Ebers Papyrus has made a lot of appearances on the show. This Egyptian medical text dates back about 3,500 years. And among other things, it contains references to using mixtures of oils and alkaline salts to wash and to treat skin diseases.
10:37 Holly Frey? There is an incredibly widely repeated story that the word soap comes from an ancient Roman legend about Mount Sapo. According to this purported legend, Mount Sapo was the site of animal sacrifices to the gods. Animals were slaughtered and burned at the top of the mountain. And then, according to the tale, after it rained, women washing their clothes in the Tiber River at the foot of the mountain found that their laundry got extra clean.
11:05 Tracy V. Wilson? This is a fun story. On the surface, it seems like it should make some reasonable amount of sense. The ash from the burning process would have combined with the fat from the animals to make a simple soap, and then rain would have washed that into the Tiber. But Mount Sapo is not a real place, and this legend only seems to show up in articles about the history of soap. I could not find anything that pointed back to an original Roman document that references this story. And it seems like any soap that could have been created as a byproduct of burned animal sacrifices would have been really heavily diluted by the time it was washed all the way down a mountainside by the rain.
11:50 Tracy V. Wilson? And then, once it was in the river, it would have been washed downstream really quickly. It does not really take that much soap to clean things. Like, a lot of people put way too much detergent in their laundry, but this all just seems like kind of a stretch. Also, while a lot of words related to soap do trace back to Latin, that word made its way into Latin from elsewhere, which we will be getting to.
12:18 Holly Frey? Roman author Pliny the Elder, who lived in the first century CE, gave a very different explanation for where soap came from than this purported Roman legend. This is in a section of his Natural History on the Treatment of scrofula, which is a form of tuberculosis. We talked about scrofula in an episode that ran as a Saturday classic in November of 2023.
12:42 Holly Frey? Specifically, Pliny wrote about how to treat ulcerated sores from scrofula. He listed a series of unpleasant sounding treatments, many of which involved dung, vinegar, animal parts, or even urine, one of the many historical uses for urine, including its being used as a cleansing agent. After all of this, probably less than appealing treatment option list, Pliny wrote, quote, "Soap too is very useful for this purpose, an invention of the Gauls for giving a reddish tint to the hair. This substance is prepared from tallow and ashes, the best ashes for the purpose being those of the beech and yolk elm.
13:25 Holly Frey? There are two kinds of it, the hard soap and the liquid, both of them much used by the people of Germany, the men in particular more than the women."
13:35 Tracy V. Wilson? Pliny the Elder died in the eruption of Mount Vesuvius, which also destroyed the Roman city of Pompeii. And a lot of sources claim that Pompeii had a soap factory. This soap factory is mentioned in pieces about soap about as often as that story of Mount Sapo is. There is a room in the ruins of Pompeii that has often been called the Soap Factory, but that moniker seems to trace back to a letter that was written in the late 18th century. There was something that had seemed kind of soap-like that had been discovered in this room, but later testing showed that it was some kind of clay like Fuller's earth. Other evidence of soap has not been found at Pompeii.
14:20 Tracy V. Wilson? Like, there's been a lot of cosmetics that have been found, things that are probably makeup, but not things that are confirmed to be soap. And it's possible that this space was really for doing laundry or for some kind of industrial production of something that you would need big vats for.
14:37 Holly Frey? A work attributed to Greek physician Galen, written roughly 100 years after the destruction of Pompeii, describes soap as being made from the tallow of oxen, goats, or sheep, and a lye of ashes strengthened with quicklime. Galen describes the best soaps as coming from Germany, and the second best is coming from the Gauls.
14:58 Tracy V. Wilson? So Pliny and Galen's descriptions of soap feed back into the origins of the term. As we said earlier, the Latin word for soap is sapo, and then that feeds into a lot of other words that are related to soap. But the word sapo probably had Germanic origins, and there are also some similar words in Turkic languages. So this suggests, but doesn't conclusively prove, that the Romans learned about soap from the Germanic peoples of Northern Europe, or the Turkic peoples of Western and Central Asia, or maybe some combination of both. It gets much easier to trace the development and manufacture of soap a bit later in history, and we're going to get into that after we pause for a sponsor break.
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17:54 Tracy V. Wilson? Guess who's back in the house? The old gays return for season two of Silver Linings, their hit podcast from iHeart's Ruby Studio in partnership with ViiV Healthcare. Just wait until you hear what hosts Robert McMillan and Jessa have in store this time around. They strut back down memory lane navigating life, love, loss, and everything that shaped them along the way. And as usual, someone just might break into song. From leather bars to bathhouses, dance floors to drag brunch, nothing stays off limits. These are the kinds of insights that can only come from experience. So listen to your elders, honey, and discover the silver linings you can take with you. All sass, zero filter, and decades of perspective from four friends
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19:54 Tracy V. Wilson? Soap making started to become a more established craft in parts of the world in the 7th and 8th centuries. And at that point, it does get easier to trace its history. Although this is a section of the episode that's not completely chronological in what we're talking about. Stuff is happening at some points roughly the same time, sometimes in sequence, but generally all in the same period of history. Before we get to that, though, we are going to talk a little bit about how soap works very quickly because that is connected to how soap making evolved as a trade.
20:32 Holly Frey? Soap is a type of surfactant or surface active agent, which lowers the surface tension of water. Surfactant molecules have two parts. One is hydrophobic, meaning it repels water. And the other is hydrophilic, meaning that it's attracted to water. Sometimes the hydrophobic end is described as lipophilic or attracted to lipids. So in soapy water, the lipophilic end of the surfactant molecule attracts fats and oils and other lipids, while the hydrophilic end keeps it suspended in the water. So the surfactant and the lipids it's attracted to can be washed away. Actions like agitation and scrubbing help this process.
21:13 Tracy V. Wilson? As we said earlier, soap forms when an alkali, like lye, interacts with a fat, like tallow. And this reaction is called saponification. It produces a fatty acid salt, that being the soap and glycerin.
21:29 Tracy V. Wilson? Tallow is rendered animal fat and early soaps made with it probably didn't smell great. Uh, the tallow was also used for other purposes, including cooking and candle making. And as people figured out how to use it to make soap, a lot of times those and other applications were seen as a higher priority than soap was.
21:52 Holly Frey? But starting in the 7th and 8th centuries, Arab soap makers started using quick lime rather than lye, which produced a harder soap. And these harder soaps started to be made in places that also had an abundance of another fat. That fat was olive oil. Over the centuries, soap making centers were established all around the Mediterranean, including Aleppo in Syria, Marseille in France, Savona in Italy, and Castile in Spain.
22:21 Tracy V. Wilson? All names that are still associated with soap. While these soaps are all made from olive oil, they all have their own distinctions, including the addition of laurel oil, or gar in Aleppo, and the addition of almond oil in Savona. By the 10th century, the city of Nablus in Palestine was becoming known for its Nablusy soap, which is also made from olive oil. At some point, people in Morocco started making a black soap from olive oil, with the soap getting that black color from macerated olives. Also, although olive oil soaps became particularly widespread, not all soaps are being made from olive oil.
23:04 Tracy V. Wilson? Another black soap, developed by the Yoruba people in what's now Nigeria, is made from shea butter, also pronounced shea butter, and sometimes that includes palm oil as well.
23:15 Holly Frey? At first, these soaps were mostly made by families or members of the community for their own use. And they were and continue to be culturally important in a lot of places. For example, Nablusy and Aleppo soaps both continue to be made through traditional methods today, although sometimes on a much larger scale than they were in earlier centuries. In 2024, the making of Aleppo gar soap in Syria and Nablusy soap in Palestine were both inscribed on UNESCO's representative list of the Intangible Cultural Heritage of Humanity.
23:49 Tracy V. Wilson? Early soap formulations tended to have a fair amount of alkali left behind in the finished product, and a lot of times that made them too harsh to use on human skin, especially on a regular basis. It might be something you would use for a specific medical purpose, but like not for day-to-day washing and bathing. So during the medieval period, when this is the case, soaps were more often used for things like laundry or cleaning surfaces, and they had other uses as well. For example, the collection of medieval manuscripts known as the Mappe Clavicula, which is sometimes translated as "The Little Key to Everything," includes numerous recipes and instructions that incorporate
24:34 Tracy V. Wilson? soap for things that aren't cleaning. This includes making a Rouen green dye, which involved smearing pure copper with the best soap, making azure dye, which involved violet flowers and soap, and making a gold solder, which required copper oxide, olive oil soap, and calquathar, which is an iron oxide.
24:59 Holly Frey? The Mappe Clavicula also includes a process for making soap. Burn some good logs and spread the ashes over a fine wickerwork or a thin meshed strong sieve. Pour hot water over the ashes so it drips through the wickerwork or the sieve. What comes out on the other side is lye. Repeat this process, pouring the lye through the ashes and collecting it again until it's very strong. Boil it until it starts to thicken and then add oil or tallow and add lime if desired. Allow this mixture to cool and pour off any liquid after the soap solids coagulate. According to this recipe, you can take this poured-off liquid and add salt to produce affer nitrum, which is used in soldering.
25:43 Tracy V. Wilson? Also, during the medieval period, Muslim chemists were working on formulations for soap that would be gentle enough for regular use on the human body.
25:54 Tracy V. Wilson? The ritual washing that Muslims perform before prayer typically involves only water or something like clean sand if there's no water available. And in most cases, soap is used for this only when it is needed. But cleanliness is also one of the core teachings of Islam. Philosopher and alchemist Abu Bakr Muhammad Ibn Zakaria al-Razi, also called Raziz, lived during this period that is known today as the Islamic Golden Age, and he developed recipes for gentle, pleasant smelling soaps and the olive oil that was needed to make it in the 10th century.
26:35 Holly Frey? By that point, guilds systems had started to develop in the Byzantine Empire and in northern and western Europe, including soap making guilds. And in much of Europe, two modes of soap making evolved. Women were often making the soap that their household would use, often in a big batch once a year, either after the harvest and processing of whatever plant the oil came from, or after the period of slaughter so that they would have the necessary animal fat. And guilds produced soap for industrial use or for use as a trade good. Guilds often had a monopoly on any soap that was being sold, and soap making guilds tended to be closely associated with the guilds that could provide them with the tallow, oil,
27:19 Holly Frey? and lye, or other alkali that they needed to do it. This also meant that soap making became interconnected with the economies of the places where these guilds operated.
27:29 Tracy V. Wilson? Yeah, a lot of times, it was not just soap. It was soap, and also candles, and also butchers, and also, like, all of them interconnected together into one big system. By the 16th century, soap making was well established in northern and western Africa and in much of Europe and Asia, including soaps for personal hygiene, also called toilet soaps, and soaps for household cleaning and an assortment of industrial uses. People in various parts of the world were also making soaps out of other ingredients, including palm oil, cottonseed oil, canola oil, and whale blubber, along with using an assortment of fragrances and dyes in the soap.
28:12 Holly Frey? But even as the soap making industry expanded and there were more soaps meant for use on people's bodies, in Europe in particular, the practice of bathing started to go into decline. And there were a lot of reasons for this. A lot of people did not have a room for bathing in their homes, so they used public bathhouses instead. And these bathhouses started to be associated with the spread of disease, including syphilis. Europe saw its first major syphilis outbreak at the end of the 15th century. People probably were not getting syphilis from bathwater, but by today's standards, these bathhouses were not particularly sanitary. Various writers on health and medicine also started to speculate
28:56 Holly Frey? that soaking in bathwater weakened people's bodies. Some of this was also just connected to bigotry and religious persecution, as Christian communities wanted to distance themselves from the ritual bathing and hygiene practices of Judaism and Islam. Christians in Europe became more focused on clean clothes than on washing their bodies, especially when they visibly appeared clean.
29:22 Tracy V. Wilson? Uh, this continued for a couple hundred years, and it makes it a little ironic that European influence became a huge factor in the spread of soap and bathing culture a few centuries later, which we will get to after a sponsor break.
29:41 Tracy V. Wilson? Guess who's back in the house? The old gays return for season two of Silver Linings, their hit podcast from iHeart's Ruby Studio in partnership with ViiV Healthcare. Just wait until you hear what hosts Robert McMillan and Jess A. have in store this time around. They strut back down memory lane, navigating life, love, loss, and everything that shaped them along the way. And as usual, someone just might break into song. From leather bars to bathhouses, dance floors to drag brunch, nothing stays off limits. These are the kinds of insights that can only come from experience. So listen to your elders, honey, and discover the silver linings you can take with you. All sass, zero filter,
30:22 Tracy V. Wilson? and decades of perspective from four friends proving that queer joy only gets better with age on the podcast that never gets old. Listen to Silver Linings, available on the iHeart Radio app, Apple Podcasts, or wherever you get your podcasts.
30:40 Speaker 04 Okay, Chicken Nugget fans, I've got huge news. The new Burger King Chicken Nuggets just dropped, and they are the crispiest, the juiciest, and the tastiest chicken nuggets ever at Burger King. Burger King heard that a lot of you didn't like the old Chicken Nuggets, so they got to work and reinvented them. To go along with the new Chicken Nuggets, a lot of the sauces were reinvented too, because better Chicken Nuggets deserve better sauces. We're talking new buffalo sauce, honey mustard, sweet and sour, and even a whole new option too, the new special savory sauce, which is only available for a limited time at participating US restaurants. I mean, you need to taste it all for yourself.
31:23 Speaker 04 This new Chicken Nugget, reinvented based on real feedback, is made with 100% white meat chicken and is now better than ever. You gotta try the new Burger King Chicken Nuggets and sauces today.
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33:22 Tracy V. Wilson? As we've said, by the 18th century, soap making was well-established as an industry in parts of Europe, Asia, and Africa. European colonists had also introduced soaps to the Americas, where it quickly grew into an industry there. But it could be difficult to make soap at a really large scale. In a lot of places, the limiting factor was the alkali needed to start the saponification process. Making lye from ashes and water was time-consuming, and it required a lot of ash. Other sources of alkali, like limestone, were also in demand for other purposes, like making plaster and mortar.
34:07 Tracy V. Wilson? Then, in 1775, the French Academy of Science offered a cash prize for the development of a process to manufacture sodium carbonate, also called washing soda or soda ash. French surgeon Nicolas Le Blanc created an inexpensive method for doing this 15 years later. It involved sodium chloride, or common table salt, along with sulfuric acid and limestone. And this development affected so many industries. In addition to its use in saponification, soda ash was used in making things like paper, glass, and porcelain. Belgian scientist Ernest Solvay later built on Le Blanc's discoveries to make a commercially viable
34:51 Tracy V. Wilson? process for making soda ash at scale. People also started to figure out exactly what was going on during the process of saponification beyond just turning fat and alkali into soap.
35:06 Tracy V. Wilson? French chemist and soap maker Michel Eugene Chevres started studying soaps and the fats that they were made from in the 18 teens. He was building on the work of earlier scientists, including French apothecary Claude Joseph Joffre, who had discovered that saponified fat was soluble in alcohol while the fat that the soap had originally been made from was not. Chevres figured out that the saponification process split a fat into two components. Those were the organic acid salt that we call soap and glycerin. From there, he started to isolate and name individual fatty acids and to study how
35:49 Tracy V. Wilson? they behaved when they were used to make both soap and candles. The isolation of glycerin from soap making also made it possible for Alfred Nobel to refine nitroglycerin into a commercial explosive that was dynamite in 1867.
36:07 Holly Frey? The isolation of different fatty acids and the ability to make inexpensive soda ash made it easier to make soaps at scale and to make a more consistent end product. Advances in transportation, including steamships and railroads, also made it possible to transport large amounts of raw materials to places that did not have an abundant supply of olive oil or shea butter or some other ingredient. This wasn't completely new. England had an established soap industry by the 13th century, including in Bristol, Coventry, and London with soaps made from tallow as well as imported olive oil. But steamships and railroads made it much easier to move raw materials and finished products.
36:51 Tracy V. Wilson? All of that progress or development combined with industrial techniques that had been in progress since the 18th century, including the discovery of steam power and a renewed focus on cleanliness and personal hygiene in Europe and North America. That included the germ theory of disease becoming more widely known and accepted. And all of that came together to turn soap into an enormous business. Most of these commercially made soaps were sold in bar form, but the first liquid soaps hit the market in the mid 19th century, and there were powdered and flaked versions by the early 20th century.
37:35 Holly Frey? The soap industry that evolved in the 19th century included a whole lot of names that are still around today. Many of them got their start producing both soap and candles, or by making candles before moving into soap. Soap and candle maker William Colgate established his company in New York in 1807. Three decades later, Cincinnati candle maker William Proctor formed a partnership with Irish soap maker James Gamble. British brothers William and James Lever established a business to make soaps from vegetable oils in 1885. B.J. Johnson created a soap made of palm and olive oils, calling it Palm Olive in 1898.
38:18 Holly Frey? Colgate and Palm Olive merged in 1928, and a year later Lever merged with Margarine Uni N.V., which had formed through the merger of two Dutch margarine manufacturers, and that formed Unilever.
38:32 Tracy V. Wilson? Back at the beginning of the show, we talked about how peoples and cultures all over the world, for essentially all of human history, have had ways to clean their bodies, and their clothes, and their environment, and have had various norms for cleanliness and hygiene. But as the soap industry industrialized and soap became widely available as a consumer product, and as social reformers focused on hygiene and cleanliness, all kinds of people started to think of soap as the only acceptable way to be clean. That included politicians, church leaders, social workers, missionaries, and soap marketers. Soap ads equated cleanliness
39:16 Tracy V. Wilson? with purity and wholesomeness, especially if that cleanliness came through the use of soap. In the 1880s, British firm Pears Soap, which would later be acquired by Unilever, quoted the Reverend Henry Ward Beecher in its advertisements, quote, "If cleanliness is next to godliness, soap must be considered a means of grace, and a clergyman who recommends moral things should be willing to recommend soap."
39:46 Holly Frey? Soap makers also equated soap with civilization and whiteness. For soaps like Ivory, this tied the color of the soap itself to the idea that it was 99.44% pure. As big soap manufacturers in the US and Europe started selling their products in places like the Pacific Islands and Africa, they ran advertisements rooted in the idea that soap would bring civilization to these places. Ads like these ran within the US as well, framing soap as civilizing indigenous communities and as washing the color from black people's skin, as though it would be preferable for their skin to be white, and as though using this soap would help them assimilate to white society.
40:31 Tracy V. Wilson? Since soaps were often marketed to women in women's magazines, this was also tied to ideas of femininity and womanhood, especially white women's purity. There are really whole books about this kind of stuff, including things like the general use of indigenous imagery in advertising and the use of caricatures of black people to sell soap and other products. This is way more than we can cover every aspect of here.
41:01 Holly Frey? This also went beyond advertising. 19th century German scientist Eustace von Liebig claimed that soap consumption was an indicator of a nation's wealth and civilization. Teachers at mission schools told indigenous children around the world that they were dirty if they didn't use soap. An added layer to this was that some of the soaps they were advocating were made with culturally important oils extracted from these same communities to be sold to people living elsewhere. This 19th century globalization of soap and the soap industry circles back to something we said at the beginning of the show about the word for soap in different parts of the
41:42 Holly Frey? world, and how in some places, it's derived from the traditional preparations that soap was replacing.
41:50 Tracy V. Wilson? Into the 20th century, new discoveries continued to affect the way soaps could be made, with a lot of those discoveries now coming from scientists who worked for major soap manufacturers. For example, Procter & Gamble patented processes for hydrogenating oils in 1909. Today, people probably think of hydrogenated oils in the context of food, but hydrogenation could help harden the fats that were used to make soap. There were multiple patents related to hydrogenation in the late 19th and early 20th centuries, and so this led to a whole series of legal battles over patents and licensing rights when it came to hydrogenation in soap making.
42:34 Holly Frey? When World War I started in 1916, many of the raw materials used to make soap were needed for other wartime applications. This led to chemists developing synthetic surfactants as a replacement. The first synthetic surfactant predated this. It was sulfonated castor oil, known as red turkey oil, and that had been discovered in 1851. But the first intentionally developed synthetic surfactants are usually credited to German scientist Fritz Gunther, who worked for BASF during World War I. Synthetically made surfactants became known as detergents, and today, a lot of things that people call soap are actually detergents.
43:17 Tracy V. Wilson? Yeah, they're still surfactants, they're still cleaning things, but they're not that technical definition of soap. Tangentially related, the first soap operas made their debuts in the 1930s. Those, of course, are serialized dramas, starting on the radio and then moving to television with soap companies as their major sponsors. That is another entirely different subject.
43:43 Holly Frey? Into the 20th century, soap manufacturers started developing more specialty products, with surfactants meant to work on specific types of soil or to be used for specific tasks. This includes the first laundry and dishwasher detergents in the 1940s and 1950s, which produce less foam so they don't cause the machines to overload with suds. The first household liquid soap meant specifically for handwashing was Soft Soap, and that debuted in 1980. The 20th century also saw an assortment of additives to different soap and detergent products, like optical brighteners, which make whites look whiter in the laundry, or enzymes meant to break down specific types of stains or oils.
44:29 Tracy V. Wilson? So, as we mentioned, there are connections between the globalization of soap and racism, colonization, and oppression. At the same time, washing your hands with soap and water really does help reduce the spread of numerous diseases. So, a lack of access to soap and clean water can have a serious and damaging effect on public health. Research at places like refugee camps and communities that are facing widespread poverty have shown a measurable reduction in certain illnesses, especially diarrhea illnesses, when people have access to soap and water.
45:10 Tracy V. Wilson? These illnesses can be fatal in young children, elderly people, and people who have other illnesses, or who are already facing malnutrition or dehydration. So, this connection between soap availability and disease reduction has led to programs to distribute soaps in places that need it, and to do things like recycle partially-used hotel soaps to distribute to poorer parts of the world.
45:37 Holly Frey? Soap.
45:40 Tracy V. Wilson? That's... Some stuff about soap, um, sometimes chronologically and sometimes not. I have listener mail about pens.
45:48 Holly Frey? Love it.
45:48 Tracy V. Wilson? From Ralph. Ralph wrote, Holly and Tracy, I really enjoyed your recent episode on the ballpoint pen. I also am very particular about the pens I use, but for a slightly different reason. I'm left-handed, so I have problems with the ink in most pens smearing as I draw my left hand across it. However, I have found that the Pilot Vball pens with green ink don't smear. The red, black, and blue ones all smear, but for some reason, the green ones don't. So that is my go-to pen of choice and has been for several years now. Plus, green is one of my favorite colors, which is a bonus. In fact, people in my office know that if something is written in green ink, it's mine. I love your show and the
46:29 Tracy V. Wilson? wide variety of topics you cover. I've been listening since the beginning of the pandemic and usually listen to your episodes while I'm out cycling along our local bike trail along the river. I'm gonna pause and say, that sounds lovely.
46:42 Holly Frey? Hmm.
46:43 Tracy V. Wilson? Uh, I have also attached my pet tax photos of my cats Madison on the floor and Savannah on the sink. These photos were taken on their 17th birthday on April 4th this year. Thanks again for all you do, Ralph. Uh, we do indeed have a kitty cat, um, with two front feet in the sink, two back feet on the edge of the counter. Um, and then, uh, this kitty cat's sibling with very, very similar face and coloring. They could almost be twins. I mean, like identical twins, not just cats born together in the same litter. Um, the cat that is on the floor, uh, named
47:25 Tracy V. Wilson? Madison looks very startled. They are both, um, they are both tabby cats with little white faces, like just little white right around their mouths and noses.
47:36 Holly Frey? Happy birthday Madison and Savannah, just months late.
47:40 Tracy V. Wilson? Yeah, this, yeah, this is from July.
47:44 Holly Frey? When their birthday was.
47:45 Tracy V. Wilson? When the birthday happened. Um, the email is from July. So thanks so much, Ralph. I just, uh, I'm technically a right-handed person. I have always had questions about whether I ought to have learned to write with my left hand. I did not understand what the teacher meant when they said, put it in the hand that it feels the most comfortable in. I was like, this feels bad in both my hands. What are you talking about? But my spouse is a lefty, and so I have seen his struggles with the world of things that are built for right-handed people.
48:16 Holly Frey? Yep. Also married to a lefty.
48:19 Tracy V. Wilson? Yeah. So, thank you for this email. If you'd like to send us a note about this or any other podcast, we are at [email protected] and you can subscribe to our show on the iHeartRadio app or wherever else you like to get your podcasts.
48:41 Tracy V. Wilson? Stuff You Missed in History Class is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.
48:55 Holly Frey? A rare disease diagnosis can change your life, but it doesn't have to define your future. In season seven of Untold Stories: Life with a Severe Autoimmune Condition, host Martine Hackett continues the conversation with people living with MG, CIDP, and the broader rare disease community, exploring what comes after diagnosis through stories of hope, progress, and connection. Produced by Ruby Studio in partnership with Argenx. Listen on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts.
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50:03 Speaker 05 Live Right, publishers of John U. Bacon's New York Times bestseller, The Gales of November, a chronicle of the S. S. Edmund Fitzgerald's 1975 shipwreck. "Never has it been told better than by Mr. Bacon in this colorful book," writes John J. Miller of The Wall Street Journal, while author Hampton Sides proclaims that it's destined to be a classic. The Gales of November, now in paperback.
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