Let’s take a few minutes to appreciate the power of soap.
Over the past few weeks, health ministries around the world have inundated us with advice. The main WHO guidelines are regularly clean your hands, avoid touching your face, cough into your bent elbow and social distancing. Most importantly, stay home if you feel unwell. The novel Coronavirus (COVID-19) has dominated airways via both media and respiratory.
So how does soap protect us from this virus and many other pathogens?
We all know the saying that oil and water do not mix. However, soap acts as a surfactant and emulsifier. When adding soap to an oil and water suspension, the soap surrounds the oil making it easier to rinse away with water. Hypothetically, oil represents dirt, grime and pathogens (viruses and bacteria).
How Was Soap Made?
Saponification is the reaction between fats and caustic salts (alkali) to produce soap and glycerine. The formula below shows a general reaction.
Around 2200 B.C. a Babylonian clay tablet detailed the formula for soap using alkali and cassia oil. Ancient Egyptians were using alkali salts, animal fats and vegetable oils. Aleppo soap is a hard soap, containing laurel berry oil, lye and olive oil. Marseille soap contains seawater, alkaline ash from sea plants and olive oil. African black soap is a soft soap derived from natural alkali ash (plantain skins, shea tree bark and palm tree leaves) mixed with coconut oil, shea butter and palm oil.
What remains consistent throughout all these recipes, whether hot or cold-pressed, is the type of alkaline used. Solid soaps require caustic soda or sodium hydroxide (NaOH). Liquid soaps use caustic potash or potassium hydroxide (KOH). No matter what the fragrance, cleaning properties, lather characteristics, bar or liquid soap. We should spend at least 20 seconds to wash our hands.
The power of soap is amazing. Remarkably, the process for soap making today has not changed much since from formula recorded by the Babylonians.