Soap and detergent, who invented it?
Soap is "a type of detergent" that is believed to have been invented almost 5000 years ago in Mesopotamia. The Romans discovered the same thing sometime during the first century. At this time, animal fat from, for example, sheep and goats was used, the saponification was done by using "lye" from ash and what was produced was called sapo. What about Sweden then? There is said to be a recipe for soap and detergent in a manuscript by the Bishop of Västerås, Peder Månsson from the beginning of the 16th century . Since then, both vegetable oils, animal fats and imported fats have been saponified in Sweden throughout the ages.
So soap is nothing new and for a very long time only soap/detergent was available. We washed everything that needed to be washed with soap/detergent and it went well until World War II became a reality and there was a shortage of raw materials for practically everything, including soap and detergent.
The war forced new methods and people started experimenting with artificial substances. Substances such as mineral oils, by-products from the petroleum industry and surfactants were used.
But everything that is manufactured and built before the war is therefore cleaned, washed and cared for with "natural" detergent and soap. Many of our finest and oldest buildings - yes, even castles - were built before 1939 and have thrived on cleaning without artificial cleaning products for a long time.
Away from the natural
In 1954, more cleaning agents with surfactants were produced than soap detergents for the first time. In the 1960s, surfactant-based shampoos broke through and then the years went all the way to the 1990s before liquid soap broke through on the market, these however contain a lot of preservatives and synthetic surfactants that can have a negative impact on both health and the environment.
So even if neither hygiene nor cleaning historically has been what it is today, we can state that it was managed with soap and detergent until fairly recently. Many of us read in school about Lubbe Nordström and his "Lort Sverige" (Dirty Sweden), a radio series that was broadcast in 1938 and made the Swedes clean and wash up properly. Before that, it was not uncommon to think that a scoop of sand on the floor could be counted as cleaning and that a bath at Christmas was what personal hygiene required. Soap scrubbing became common during the second half of the 19th century when rag rugs began to be laid in the fine rooms.
Surfactants
What happens purely chemically is that the surfactants in the detergent/soap reduce the surface tension and make it possible to wash away the dirt particles (often grease). We notice that foam forms from detergent, soap and shampoo and the dirt can be washed off more easily and there we have the whole point with detergent/soap, we needed and still need this to wash ourselves, our clothes and for cleaning and washing dishes because mechanical cleaning alone is not enough. We would, for example, not be satisfied with wiping the dishes with a cloth or brushing the clothes clean. Something more is needed, a surfactant! A surfactant is usually described as "a tadpole" with a hydrophobic tail and a hydrophilic head. The surfactant's tail penetrates the greasy dirt while the head remains "on the outside" and it is when this happens that you notice that you can easily wash away the dirt.
There are tons of different surfactants but the surfactants found in soap (soap without added artificial surfactants) are the simplest and oldest form, anionic surfactants. The molecules have a water-soluble-fat-repellent and a fat-soluble-water-repellent part. In the water-soluble part, the surface-active potassium ion is negatively electrically charged.
The difference between detergent and soap
The common perception is that the difference between detergent and soap is that soap is produced by saponification with potassium hydroxide and detergent by saponification with sodium hydroxide. Soap is therefore sometimes called potassium soap.
Swedish is unusual in that we have different words for soap and detergent. Many other languages have only one word, soap (soap, savon, Seife, saebe etc.).
Many would probably say that if saponification occurs with sodium hydroxide, it is detergent and not soap.
Theories online
There are "theories" circulating that you cannot clean tiled bathrooms with soap but with a little background (according to the above) you quickly realize that you would also not be able to wash yourself in the shower with detergent if that were the case, but it is not at all strange that such things are floating around on the internet, there are plenty of industries that all want to sell their products and it is seldom that the old, more natural alternative (detergent/soap) is the most profitable business and thus not the ones that produce the most advertising.
City and Country
It is told that soap-making women went around the farms and offered their services in old Sweden's agrarian society. The soap was cooked in the laundry cauldron, the sauna or out in the yard which was fired with wood. And the lye came from ash (ash from deciduous trees) that was prepared in a lye tank or directly in the cauldron. In southern Sweden, you could cook green soap when the fat raw material was hemp oil, which made the soap naturally green. The soap became yellow from light oils and a bit "milky" from animal fats. In cities where people didn't slaughter and cook their own soap, there were soap manufacturers. The first Swedish privilege to establish a potash distillery and soap works was granted in 1654 by Queen Christina to Hamilton's Potash Compani.
Superstitions and old wives' tales
Soap is not entirely easy to make, you have to get the saponification process/saponification started and it doesn't succeed if you don't have the right proportions, temperature and time. It's easy to imagine how a failed soap cooking could be blamed on witchcraft and mythical creatures instead of a measurement error ;) So preferably the soap cooking should take place in secret, there should be no malicious or unhappy people nearby, they could bewitch the cooking just by glancing in the cauldron. Other forbidden things to do were to say the word soap aloud or not to stir in the same direction in the cauldron throughout the cooking. There was also talk of magical soap with snakes and bird hearts in the recipes. All this is of course superstition and old wives' tales but it is easy to understand how it came about, it is a bit "magical" every time the saponification starts in the cauldron and fat slowly turns into soap before our eyes.