How Does Soap Work: Types of Soap, History, Uses

You use it every day, multiple times a day. It’s often taken for granted, a simple bar or liquid that we lather up and rinse off. But have you ever wondered how this seemingly ordinary substance works? This blog will take you through the fascinating world of soap, covering its history, types, how it works, the soap-making process, the right way to use soap, and the best soaps for bathing, laundry, and dishwashing. We’ll also explore recent research and share some intriguing facts about soap. So, let’s uncover the secrets behind this everyday marvel!

What is a Soap?

Soap is a cleansing agent that is made from natural fats and oils combined with an alkali, such as lye (sodium hydroxide). It is a surfactant, meaning it reduces the surface tension of water, allowing it to spread and penetrate more easily. This property makes soap an effective cleaning tool that removes dirt, oil, and bacteria from surfaces and skin.

The History of Soap

The history of soap dates back to ancient Babylon around 2800 BC. The Babylonians made soap from animal fats and wood ash. The practice of soap-making spread to ancient Egypt, Rome, and eventually throughout Europe. During the Middle Ages, soap was made by combining animal fats with lye, a process that remained largely unchanged until the Industrial Revolution in the 19th century, when soap production became more sophisticated and widespread.

Types of Soap

To better understand the diverse world of soaps, let’s explore the different types available. Each type of soap serves a unique purpose and has distinct characteristics. Check the following table to know more in detail.

Also Read: What Did People Use Before Toilet Paper?

How Does Soap Work?

Soap works through a process known as emulsification. Here’s a simplified explanation:

1. Hydrophobic and Hydrophilic Ends

Soap molecules have two ends – a hydrophobic (water-hating) tail and a hydrophilic (water-loving) head.

The Head: It’s like the social butterfly of the molecule, eager to mingle with the water molecules.

The Tail: It’s the shy introvert of the molecule, preferring to hang out with oily and greasy substances.

2. Breaking Up Grease

When soap is mixed with water, the hydrophobic tails attach to grease and oil while the hydrophilic heads remain in the water.

3. Forming Micelles

The soap molecules surround the grease, forming structures called micelles, with the grease trapped in the center. This is where the magic happens.

4. Rinsing Away

The micelles are suspended in water and can be rinsed away, taking the grease and dirt with them.

It’s like a team effort between the soap and the water. The soap acts as a bridge, connecting the oily dirt to the water, allowing it to be carried away effortlessly.

The Soap-Making Process Steps

Ever wondered how that gentle bar of soap in your hand came to be? Let’s lift the lid of soap making. The four major processes involved in soap making are:

1. Saponification

It involves the chemical reaction between fats or oils and an alkali. Here’s a step-by-step guide:

Step 1 – Preparation

The fats or oils (e.g., olive oil, coconut oil) are chosen and the lye and water are measured

Step 2 – Mixing Lye and Water

The lye is now carefully mixed with water to create a high exothermic reaction.

Step 3 – Combining Fats and Oils

The fats or oils are heated and then slowly the lye mixture is added while stirring continuously.

Step 4 – Saponification

As the mixture thickens, it undergoes saponification, where the fats and lye react to form soap and glycerin.

Step 5 – Pouring into Molds

The thickened mixture is poured into molds to set.

Step 6 – Curing

The soap to cured for several weeks to harden and develop its properties.

2. Cold Process Soap Making

Cold process soap making involves creating soap from scratch using oils, fats, and lye (sodium hydroxide) without the application of heat. The process involves:

Step 1 – Preparation

• Measure and mix the lye with water. This creates a lye solution that must cool to a safe temperature before mixing with oils.
• Prepare your oils and fats by heating them until they’re melted and combined.

Step 2 – Mixing

• Combine the lye solution with the oils and fats. This mixture is blended using an immersion blender until it reaches “trace,” which is when it thickens and leaves a trail when drizzled over the surface.
• At this stage, you can add colorants, fragrances, or other additives.

Step 3 – Pouring and Curing

• Pour the mixture into molds and let it set. It usually needs to be insulated to maintain warmth and aid the saponification process.
• After 24-48 hours, the soap is removed from the mold and cut into bars.
• Cure the soap for 4-6 weeks. During this time, the soap hardens and the pH levels decrease, making it safe and mild for the skin.

3. Hot Process Soap Making

Hot process soap making involves heating the soap mixture to speed up the saponification process. This is often done in a slow cooker or a double boiler. Their process is:

Step 1- Preparation

Like a cold process, measure and mix the lye with water, and prepare your oils.

Step 2 – Mixing

Combine the lye solution with the oils. Cook the mixture on low heat. The soap mixture goes through various stages, eventually reaching the “gel phase,” where it thickens and becomes translucent.

Step 3 – Cooking and Additives

Once saponification is complete, you can add colors, fragrances, or other additives. The mixture is then poured into molds.

Step 4 – Cooling

The soap cools and hardens more quickly than cold-process soap. It usually needs just 1-2 days to set before it’s ready to use.

4. Rebatching Process

Rebatching, or “milling,” involves taking pre-made soap (either homemade or store-bought) and melting it down to add additional ingredients or modify its properties. The steps are:

Step 1 – Preparation

Shred or cut the pre-made soap into small pieces.

Step 2 – Melting

Melt the soap in a double boiler or a slow cooker. This process is gentle to avoid overheating.

Step 3 – Additives

Once melted, you can add colorants, fragrances, exfoliants, or other additives. Mix thoroughly.

Step 4 – Molding

Pour the modified soap into molds and let it set. It usually cools and hardens within a day.

The Right Way to Use Soap

Using soap correctly enhances its effectiveness and benefits:

1. Wet Your Hands or Body: Use water to wet the area you’re cleaning.
2. Apply Soap: Rub the soap to create a lather.
3. Scrub Thoroughly: Scrub for at least 20 seconds, ensuring you cover all areas.
4. Rinse Well: Rinse with clean water to remove all soap residue.
5. Dry: Dry with a clean towel or air dry.

Popular Soap Brands

While specific rankings may fluctuate, these famous brands consistently appear on “best of” lists and are widely recognized for their quality:

Recent Research About Soap

• Robert Tolppi, 23, the influencer, who frequently shares bizarre clips for his 1.5 million followers on TikTok, has gained internet fame by turning his 400ccs of fat removed during his liposuction into homemade soap.

• Used cooking oil is used to make high-quality soap with sustainable and eco-friendly manufacturing practices.
• Researchers have discovered that a particularly promising electrolyte for extending the lifespan of lithium batteries features intricate nanostructures resembling the micelle formations found in soapy water.
• Scientists at The University of Texas have found that adding small quantities of liquid soap to some classes of pesticides can boost their potency by more than ten-fold against Malaria-Carrying Mosquitoes.
• A team of scientists in Marburg, Germany, discovered that sodium laureth sulfate – found in many liquid and household soaps can kill the virus that causes COVID-19.
• Heman Bekele, a 14-year-old from Fairfax, Virginia has created a Melanoma Treating Soap (MTS) which is charged with different cancer-fighting chemicals that could treat skin cancer

Frequently Asked Questions on Soaps

1. What chemical makes soap lather?

The chemical responsible for making soap lather is sodium lauryl sulfate (SLS). SLS is a surfactant that reduces surface tension, allowing soap to create bubbles and foam.

2. Why don’t some soaps don’t lather?

Some soaps don’t lather well due to the presence of hard water. Additionally, soaps with fewer or no added surfactants, such as sodium lauryl sulfate, may produce less lather.

3. Can I make my own soap at home?

Yes, you can make your own soap at home with the right ingredients and safety precautions.

4. Is Soap carving a hobby?

Yes, it is a popular hobby that involves sculpting designs and shapes out of bars of soap. It is enjoyed for its simplicity, accessibility, and the satisfying creative outlet it provides.

5. Why does soap not dissolve in water?

Soap does dissolve in water, but if it appears not to, it could be due to hard water. Hard water contains high levels of calcium and magnesium ions that react with soap to form an insoluble residue called soap scum, which doesn’t dissolve easily.

6. Why does soap make eyes sting?

Because the chemicals in soap, particularly alkaline ingredients like lye, can cause discomfort and a stinging sensation when they come into contact with the eyes.

7. Is tear-free soap real?

Yes, it is real. Tear-free soaps are formulated with gentle ingredients that maintain a pH balance similar to that of natural tears, reducing irritation and stinging when they come into contact with the eyes.

8. Why aren’t all soaps tear-free?

Because making a soap gentle enough to avoid eye irritation often requires specific formulations and milder ingredients and regular soaps do not have such formulations.

9. Do germs grow on soap?

Germs can transfer to the surface of soap, but they generally do not thrive or multiply there. 

10. How do I know if a soap is bad?

You can tell if a soap is bad if it has an unusual or rancid smell, changed color, developed a slimy or cracked texture, or no longer lathers well. 

11. How do you stop soap from getting mushy?

To prevent soap from getting mushy, use a soap dish with proper drainage to keep it dry between uses. 

12. How is fragrance added to soap?

The fragrance is added to soap by mixing in essential oils or fragrance oils during the soap-making process, usually at the end of the saponification process.

The Soap Story

Soap is more than just a cleansing agent; it has a rich history and a complex mechanism that makes it effective in maintaining hygiene. Understanding how soap works and its various types from our blog can help you make informed choices. So, the next time you lather up, take a moment to marvel at the science behind, “How Does Soap Work”.