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How to Make Hot Process Liquid Soap

Liquid Soap Making


How to Make Liquid Soap

My Recipe AND Method – How to Make Hot Process Liquid Soap

Olive oil makes a beautiful soap, here is a recipe that once again teams two of the best oils for making soap together. Olive Oil has traditionally been used for it’s ability to create a lovely nourishing and gentle soap and Coconut Oil is used to make this a fantastic general purpose soap, providing us with a great lather. This soap can be used for everyday body cleansing, hand soap or in fact bubble bath. Too easy. I like to use ingredients that are readily available too. You can purchase these at the supermarket along with your groceries.
Liquid Soap is easy to make. If you’ve never made liquid soap before the secret is to ‘relax’. Liquid soap is not ‘quick’ to make, rather it is best made over a couple of days. Here is a recipe and method that I’m sure you’ll enjoy. It’s an easy recipe for anyone to try out.

Once again I’d like to remind you that if you’ve never made soap before – you’ll need to pay attention to your personal safety and wear appropriate safety gear such as rubber gloves, a face mask, goggles, closed in footwear and an apron. You should not touch the ingredients at all during the process and if you do happen to inadvertently spill some on yourself, wash it off immediately. That being said, the majority of people really enjoy this process. It’s amazing once you get the hang of it.

Liquid Soap is a very versatile product used for a multitude of purposes. General Cleaning, Laundry Liquid, Shampoo, Dog Soap, Horse Soap, Bubble Bath, Liquid Body Wash and the list goes on. This type of soap is commonly referred to by many as ‘Castile Soap’, you know, the one made by Dr. Bronner? Note that a true Castile Soap is a pure Olive Oil soap – which is made the same way. This particular brand is so well known that people know exactly what you’re talking about – it’s used as a base in heaps of products. Well, I’m here to tell you that any oils can be used to make liquid soap and each oil will offer a different result. A little research and you’ll be creating your own personalised soap in no time flat. This ‘Liquid Soap’ can be used on it’s own, or used to create a multitude of useful products.

Each oil used in a soap recipe brings it’s own unique qualities to the finished product in a few different ways – it can alter how well the soap cleans, if it’s nourishing, if it offers good lather, weather it provides us with any creaminess, if it has any antibacterial or healing qualities that can be utilized to our benefit, in the soap. The colour of the oils used will also effect the finished colour of the soap. With experience, you’ll notice for yourself how your recipes differ and most importantly, how you like it. Many soap makers spend hours formulating recipes in order to create the ‘perfect soap’. The purpose of this post is to offer assistance to those that have never made liquid soap before, giving you a tried and proven recipe and method to follow. When you know what you’re doing, then you have a place to start your research and learn more.


• 467gms olive oil
• 198grams coconut oil
• 153gms potassium hydroxide
• 252gms distilled or filtered water

• 1384grams distilled or filtered water (FOR DILUTION)

• essential oils, optional

My recipe yields about 2 Ltrs of Liquid Soap with a 50% soap content in water. It has a 1% superfat included.

The Process

1. Weigh your olive oil and coconut oil and place them into the slow cooker. Turn on low and gently heat them while you prepare your lye mixture (potassium hydroxide & water).
2. In a separate stainless steel bowl, weigh out your water (not by measure) into the bowl (must be by weight).
3. In a separate container, such as a recycled butter container weigh out your Potassium Hydroxide.
4. Slowly add the weighed potassium hydroxide into the water (must be added to the water in the stainless steel bowl). Stir this lye mixture gently and continuously until it stops crackling/bubbling/foaming, mix with a stainless whisk or rubber spatula until you see the crystals are dissolved into the water and then allow this liquid to go clear. Don’t be alarmed at any sounds or reactions you may hear. (Potassium hydroxide reacts slightly differently than sodium hydroxide in water.) This part can be done outside if you are concerned with the fumes or are unsure of the process.
5. When the potassium hydroxide is all mixed into the water and the solution appears clear, take it to your oils and pour your water/potassium hydroxide slowly and steadily into the oils. Don’t worry about the temperature as it’s not important (unlike cold process soap).
6. Carefully stir by hand for 5 minutes to be sure all the oils come into contact with all of the potassium hydroxide.
7. After 5 minutes of hand stirring, begin mixing with a stick blender (not beaters as you want NO SPLASH). It could take anywhere from 15-30 minutes to achieve a thick “trace.” (In soap making, trace is normally when the mixture resembles a thin custard consistency, but with potassium hydroxide trace might look more like apple sauce.)
8. The mixture might look like it’s going to separate, and look like lumpy apple sauce, don’t stop mixing until you have a nice thick custard consistency, we want to make really sure that your soap will cook properly.
9. Now that it’s a nice thick custard, Cook in the slow cooker/crock pot for about 30 minutes with the lid on. Check after 30 minutes buy giving it a good stir. You’ll begin quite quickly to notice it go through quite a few changes or stages.
10. Check every 30 minutes for 3-4 hours.

Stages to look for
During the 3-4 hour cooking stage, your soap mixture will go through several stages. They’ll look like this:
• Trace – thick pudding to applesauce
• Custard-like with small bubbles
• Watery mashed potatoes
• Taffy Sticky Toffee
• Chunky to creamy petroleum jelly
• Translucent (not clear) petroleum jelly

Each stage could take 30 minutes or longer. Be patient! When I did this the first time, I thought it would never work and just when I was going to give up, it finally came together. I’ve never had a disaster yet, so I’m sure you won’t either. You’ll be able to stir it at every stage, whenever you want. You’ll need to stir with a good solid wooden spoon & even a solid potato masher. It will be difficult, but keep going! You want to keep cooking until you feel it’s translucent. If you need to go out, just turn off the pot and it’ll do the rest itself with the residual heat in the slow cooker. Quite often I’ll cook it for a couple of hours and then just turn the pot off and let it finish off by itself, most of the time I jump into bed, wake up the next morning and it’s done. Relax, it’ll happen. When you think it’s ready – do this next step.

Testing the soap for Clarity & last stages

When you get to the last stage and it looks translucent, you can test it. Add a teaspoon of soap paste to about 50mls of boiling water. Stir it until dissolved, it’ll take a bit of stirring. Let this sit a few minutes. If it turns clear or is slightly cloudy, it’s ready. If it’s really cloudy or milky, cook your soap another 30 minutes or so or just let the residual heat in the pot do it’s job. Best thing is to go and do something else, with the pot off. Come and check it again and you’ll notice it getting more translucent. Test for clarity again. If it’s still cloudy, you may still need to cook it.. This step will help determine if the soap has gelled. This occurs when all of the oil particles have successfully saponified into ‘soap’. The chemical reaction is complete.
If it’s clear when tested, then you can go to the next step. If you’re beside yourself and really unsure and you’ve cooked and cooked for a period of 5 or more hours, just proceed to the next step. It would suffice to say that it has saponified and you just haven’t had enough insight to know that it has. It can take an experienced eye to get this part right. Your soap will work, it just may be a little cloudy, if a complete saponification had not been reached. You’ll learn this part with a little experience – knowing what the different stages look like will help you and you’ll learn more with each and every batch you make.

Now that you’ve cooked your soap paste and it is complete, you can actually store it as a paste in an air tight container indefinitely. You can then dilute as little or as much as you want, when you want it. There is no hurry to do the next stage of ‘dilution’ – you can do it when you’re ready.

The Dilution

Now that you have a nice thick paste, you can weigh out your dilution water. I like to use boiling hot water for this as it helps to dissolve the soap paste and give it a really good head start. You can however, just add room temp or even cold water, it’ll just take longer to dilute the soap paste. So if you like to get things moving quickly, just boil your kettle and use this right away to dilute your soap paste. As a general rule, I like to add the dilution water at a ratio of 2 parts water to 1 part actual soap paste. If you add up the total weight of oils plus the potassium hydroxide, that we have used here in this recipe – it equals 818gms. Multiply this by 2 = 1636gms, then subtract the 252gms of water used to make your lye, so this equals 1384gms of water to add for the dilution. This is a good amount to start your dilution with and will result in a 50% soap content in water, which will yeild a lovely thick honey like liquid soap, you can always add more water to make it thinner, personally I love a nice thick consistency depending on it’s end use. Ensure that you weigh your dilution water out before adding it to your soap pot (after boiling it) maintaining the heat. You can do this dilution straight into the same crock pot or you may choose to transfer your soap paste to a bucket (with a lid). Either way just add the water and give it a really good stir.

If you’re in a hurry (like me) all I do is add the boiling hot water, to my already hot (or reheated, if you’ve had it stored) soap paste, in my crock pot or a bucket, whichever you prefer. I maintain the heat in the crock pot for as long as I have ‘spare time’, keeping the lid on to prevent evaporation, a crock pot does help you maintain a lovely steady heat. Mush it around gently to help break up any big lumps of soap paste to aid the process. You’ll have lumpy bits of soap floating around in the water. Chances are that it will take a couple of hours to dissolve and then still be a little lumpy. Then just put the lid on, turn the crock pot off and walk away.

I actually leave it at this point until the next day and quite possibly until the 2nd day after making it (or when I get a chance). I’ve just learnt to leave it alone and let it do it’s thing. It will eventually turn into a beautiful thick liquid soap concentrate that you can be very proud of. If you find that the viscosity is just too thick and you’ve got lumpy goop, even after 2 days, simply add a little more water. If it’s not dissolving after this time, all it needs is more water and another gentle stir and a bit more time.

Once your soap is all dissolved and there are no lumps, it’s time to pull out all your empty bottles that you’ve saved for this purpose and fill them up.

I’ll take this opportunity to talk about BORAX, many people like to make up a solution with Borax and Water at a ratio of 1:2, lets say 80gm Borax to 160gm Water, adding this to the soap pot at the same time as the dilution water or shortly after. This will indeed help your soap to dilute and will neutralise & thicken all in one go. This method is however a little outdated, we know a lot more about liquid soap now. I and many others prefer not to add Borax to soap that is going to be used on the Body, it’s my belief that it’s not necessary and I leave it out. Please conduct your own research about this and by all means, if you are happy to use it – go right ahead. It does work by helping to dilute your soap quicker, it helps prevent the soap from congealing again (when you are trying to dilute it) and it also helps to thicken your soap.

If your soap is for cleaning and laundry use, go ahead and add the Borax, as it’s a wonderful cleaner and stain remover for your clothes. Inconclusive research has been conducted, in my view, about the use of Borax, some people say it’s harmful to our environment and for this reason, you may opt to leave it out. It’s been used for
decades as a fantastic cleaner though, so the choice is yours. I generally use it in my cleaning products and leave it out of my body care products as I feel it’s a little harsh on your skin/face/hair etc.

TIP – How to Thicken your soap? A final tweak to the viscosity, is achieved with the addition of fine table salt,
dissolved in a little boiling water, then added to your soap. Eg 50gm Salt into 100gm Water.

The Rest Period

Now that you’ve ladled your soap into a large jar or bottles. I use huge preserving jars/bottles for this, I’ve got them lined up everywhere. Secure the lids and leave them for a week or so. This allows any solid particles to settle to the bottom ‘this is the sequestering period’. From here you can create all those beautiful liquid soaps you’ve been dreaming about. Making bubble bath for the kids, foamy soap for the kitchen, liquid pump soap for your bathroom, add a bit of colour and essential oil and give it away as gifts to your friends and family. They’ll think your marvellous. Please label your bottles including all the ingredients that you’ve used and enjoy it. If you’d like to add essential oils for scent do so at a rate of no more than 1% of the liquid soap weight, that you are making up. So for a 250ml bottle you’d add no more than 2.5gm of essential oil or a blend of essential oils equal to 2.5gm per 250ml of product.

I’ve used mine for shampoo, body wash, dish soap, hand soap, bubble bath, foamy soaps and laundry liquid. Just a note, if you’re making shampoo try using a blend of oils in your recipe that are suited for the particular purpose you have in mind. Eg. Your hair responds well to oils like Jojoba, Hemp, Avocado, Apricot Kernel. When you use different oils please note that the amount of Potassium Hydroxide and Water will change. If you’re wanting to formulate your own recipes – start by checking out one of the soap lye calculators to be found on the internet. Here’s my favourite


Thoroughly neutralized soaps with fresh, clean-smelling oils should not need a preservative. If you feel more comfortable adding a preservative, you’ll need to conduct your own research into one that you like. The only time a preservative is paramount – is when you further dilute the soap with water to make a foamy type soap where you’d use say 30% liquid soap concentrate and 70% water to make up the foaming product. In this instance a preservative is required to prevent bacteria from growing in this ‘added water content’

.The same woud apply for any other product that you may use your liquid soap as part of the recipe, such as a facial scrub.

This recipe and method is to be used as a guide only, there are many methods and different ways that can be used to make liquid soap, this is just a method that I recommend as being an easy way to get started. It does not take into account any personal circumstances such as sensitivities or allergies to the ingredients and I recommended to be careful and informed when selecting your ingredients for making soap. For this reason this recipe is a general guide only and should not be taken any other way. If you change the oils used for the recipe – you need to alter the amount of potassium hydroxide used and also the water content and you should do so only with the knowledge of how to do so. I hope this information is useful for those interested in the hobby. Many thanks and Happy Soaping.

Recipe by Yvonne Cowell © 2017 of Simply Natural Soap Making Supplies