Natural Soap making for beginners

     The easy guide for a complete Newbie to learn how to make soap bars from scratch

The beautiful spoon

Ready to start your Soap love story? Let’s walk through the science, safety, ingredients, and process so that you can also make your homemade soap. 

This article includes the following :

  • What’s soap in chemistry?

  • Differences between Cold Process vs Hot process Soap 

  • What's Lye? Is it bad for skin? 

  • How do you select your oils?

  • Calculating the right amount of Lye for your Oils

  • All you need to make Cold process Soap ( tools and ingredients)

  • Safety rules 

  • Step by step process to make handmade Soap

  • Notes about cleaning up your tools

  • Recipe for your first ever batch of soap

What’s soap in chemistry?

Surprise, surprise, soap is a Salt ! ( whaaaat?!).Yes, soap  is a balanced combination of a fatty acids (natural oils) and lye, which results in what is known as “alkalai salt,” or a salt that is basic on the pH scale. A cutie, cleansing and moisturing creation.

The basic process of Cold process soap making is:

  1. Calculate your right amount of water, oils and lye 

  2. Prepare the solution: 

    1. Mix water and lye, set aside to cool

    2. Melt oils, set aside to cool

  3. Blend lye water and oils to form a soap “batter”

  4. Pour into mold and let harden for a day

  5. Turn out of mold, cut into bars and let cure for 3-4 weeks.


Differences between Cold Process vs Hot process Soap 

Any soap is made with oils and lye. 

In Cold process you prepare first the lye with the water (or even milk) and, in a separate container, you combine the oils. When the temperatures of each (oils & lye solution) are lower than 40 C° and at max within 10-15 degrees of each other you pour the lye solution inside the oils and use an immersion blender to bring the mixture to trace (thick batter). Finally you pour into your mold and leave it to rest for 24h (soap will reach the gel phase inside the mould) before un molding. 


Hot process soap is also made with oils and lye. However, they are all mixed together and heated in the slow cooker, somewhere between 60C° and 80C°. The slow cooker helps that batter go through saponification until the soap reaches gel phase (1-2 hours). 


What's Lye? Is it bad for skin? 

Lye is necessary to make the soap reaction. That means that once you have a soap, you shouldn't have any sodium hydroxide left. Usually soap-makers actually play it safe and add extra fat or oil (“superfatting”) to make sure there's no excess sodium hydroxide;

Lye is also known as sodium hydroxide and is a very caustic substance (the contrary of acid). Traditionally this was made from ashes (have you ever been told that your grandma made laundry with ashes? Here you go, now you know how ! ). 

Pure lye is as dangerous as a strong acid. Indeed this substance is very dry and at the contact with skin it will absorb moisture, it can leave marks on countertops, and cause blindness if it splashes in your eyes.

Don’t run away, there is nothing to be scared of if you follow safety guidelines.

How do you select your oils?

This is the key part when it comes to “formulating your soap”. If you want to create your own soap you will need to study a bit the property of each oil in order to get the desired final result ( moisturizing power, leathering power, firmness etc..). I will make a dedicated article about this soon but, to give you some hints already.

For example:

  • Olive oil is very moisturizing
  • Coconut oil helps harden the bar and will give you bubbles
  • Castor oil creates lots of lather
  • Shea butter nourishes the skin and hardens the bar


Calculating the right amount of Lye for your Oils

Oils will neutralize your lye solution, therefore you need to use enough quantity of lye needed to allow the soap reaction to happen and your soap batter to harden but not too much in order to make the lye fully disappear into the reaction. 

The lye is basically going to “gobble up” the oils and saponify them. But, watch out, each oil requires a certain amount of lye to be saponified. It is a chemical property of that oil, known as its “saponification value” and It’s different for each one.

The way we figure this out is to use something called a lye calculator. There are many of them available for free online. My favourite is the Soap Calculator from Mendrulandia 

All you need to make Cold process Soap ( tools and ingredients)

  • Water (or another water based liquid like animal milk, vegetal milk or infused water). Before using milk, or any other liquid with sugars inside, I suggest to freeze them before mixing with lye. This is to prevent the solution to “scroch” (a smelly yellow state) due to the high temperature that the lye will generate by reacting with sugar inside the liquid 

  • A digital scale. Remember, this is chemistry and things have to be precise.

  • A stick blender. Mixing by hand doesn’t work properly and your soap might remain liquid 

  • Plastic or glass pots (never steal or alluminion since they react with lye) and a silicon spatula for melting oils and blending things.

  • A mold to pour the soap into. This can be a rectangular soap mould, an old muffins’ mould or even the bottom of your carton or milk (do not hesitate to get creative, to reuse and recycle your containers). My only tip: use a container which is flexible enough to lift the soap from it once firm not to risk cracking it. Otherwise, line it up with baking paper to easily unmould your soap

  • Safety gears: safety glasses, a mask and latex gloves


All you need for soap making

Safety rules 


Lye is dangerous but it doesn’t have to be scary. Yet, it deserves to be handled with care and to respect safety rules gear. 

5 key rules of working with lye are: 

  • Proper storage: keep it out of reach from children, pets and anyone who does not know how to handle lye. Never use containers that might be confused with something else ( i.e. sugar) and mark outside that it is a dangerous good to prevent someone from drinking it.

  • Keep concentration: interruptions might cause distractions and mistakes

  • Safety gear (see paragraph before)

  • Work in open air ( or at least, make the lye solution in a well ventilated area) since lye when in contact with water will shoot way up in temperature and will also release fumes.

  • Pour lye into water and never the contrary ! If you do the contrary, your water might splash outside the container.



Step by step process to make handmade Soap


Step 1: Set up your formula, ingredients and tools 

Get all you need ready to use. Here is a checklist for your soap making preparation:

  • Identify the recipe you want to try out

  • Pick up your natural oils,, water and lye

  • Collect your tools (gears, blender, spatula and moulds)

  • Get out your scale, your stick blender

Everything needs to be measured separately before you begin. 

Step 2: Prepare the lye solution

Mix the lye into the water and mix thoroughly, until the lye dissolves.The temperature will rise up to 90 C°, It will be hot. Set it aside to cool in a safe, well ventilated place.

lye solution

olive oil
Step 3: Prepare the Oils

Measure out your oils, separately. Mix and melt the oils in a bain marie (or even in the microwave using a microwave safe container). Don’t make them too hot (maximum 60C°, depending on the melting point of each oil this can even be less.) . Let all the components cool down to 30-40 C° at least. As long as the oils are still melted and the lye and oils are relatively similar in temperature, it will work fine.
Step 4: Blend the lye solution and the oils together

Soap batter at trace
Once everything has cooled down, separately, you are ready to blend them together with your stick blender. Blend for at least 60 sec, at first the liquid starts becoming cloudy then it increases its density and becomes thicker with no oil splotches. Always immerge the blender before switching it on in order to avoid the risk of splashing. You can stop blending when your soap batter reaches “trace”. Trace means that when you lift up your blender and soap batter comes off of it (lo

At this point, you would add colors, fragrance or spices (i.e in this picture I used cinnamon) if you were using them, but I wouldn’t recommend either for your first batch since they increase the level of difficulty.

Soap with cinnamon

Step 6: Pour and cure

Once you have reached the trace level, immediately pour the soap batter into the mold ( for your first soaps I suggest using mono-portions moulds like the one of muffins so that you don’t have to master the “cutting phase” and risk cracking your soap).. Depending on the oils, it will start hardening right away, so move quickly. If you used olive oil the hardening tends to happen slowly, therefore it would be a good idea to make a 100% Olive oil soap for your first batch (this is the Marsiglia Soap style).

Pour it right in and smooth out the top with a spatula or, if you are feeling creative, wait for the soap to harden a bit before gel phase and make some Soap Curls using a spoon.

soap curls


As soap cures, it will heat up. Sometimes it will heat up a lot and go through something called “gel phase”. It gets bright, translucent, and very hot. It’s not a problem, and some people prefer it, because it makes colors brighter. If you don’t want the gel phase or your soap contains already sugar elements that will heat up the batter  ( i.e. honey) you can cover the mould with film/a cotton cloth and put the soap in the freezer.

Step 7: Un mould & refine

Once it has cured for 24 hours, it’s time to un mold and keep it in a well ventilated space. At this moment you might want to use a razor to refine the shape and smooth out the borders. Here below you can see my soap before...

honey and cinnamon soap

...and after the "refining" process :)

Honey and cinnamon soap

Continue using gloves at this point, remember that the saponification process will end after 48h and there is still some free lye before that. Natural soap needs time to finish drying out so the bar can get harder and last longer (the risk when it is too soft is that it will easily melt into water). You can just leave the bars on an old towel for 3-4 weeks and turn them every few days to dry them evenly.

Notes about cleaning up your tools

There are 2 philosophies to handle the tools after your soap making process:

Option 1: While still using your safety glasses and gloves, you can rinse out everything from the pots and tools before it hardens into soap. You’ll need to be careful if you choose this method, because the lye is still very caustic at this stage.

Option 2: You could also let everything sit and turn into soap and then just wash it out with its own soap. This is what I have adopted lately since I find it much faster to do once the oils are “ no more oily”.

Recipe for your first ever batch of soap  I suggest making a block of “Savon de Marseille” without sea salt since:

  • It is an easy recipe with 100% olive oil 

  • There are no strange ingredients, like beeswax or honey (they are lovely in soap but behave a bit differently and can speed up your saponification).

  • You don't have to attempt a fancy design or a full rectangular block of soap, try simple mono-portion moulds

Recipes for the more experienced soap maker

I hope that your Soap Love Story will start soon :)
Please comment below to tell me if you found this article useful or you have more questions on topics I did not cover.

Beautifully yours,


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