How To Make Soap Using Cold Process

Basic homemade soap that leaves skin feeling soft and smooth
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Here’s how to make soap using the cold process method, it seems complicated at first, but it’s quite easy once you get started.

This is one of four different soap making methods I use here on SavvyHomemade. I’ve found them all to be extremely addictive, and it’s one of the most wonderfully rewarding hobbies.

Let’s begin with the basics.

Below you’ll find my cold process soap making video and all of the information you need to get started, along with the basic soap recipe that I’ve made dozens of times. This recipe is one of my favorites, it’s made with simple ingredients to make a great creamy natural soap bar, it holds a good hardness and lathers up very well.

After you’ve mastered the basic cold process soap technique, I recommend that you take it a step further by creating your own unique soap from scratch using my calculator and formulation guide.

Basic homemade soap that leaves skin feeling soft and smooth

You also have some other techniques for soap making, such or my recent liquid soap tutorial. Or there’s the hot process soap which is quicker than cold process and less volatile, but perhaps not as pretty. And finally, you have the simplest form of soapmaking known as the melt & pour process if you want to make soap without using lye.

Begin By Watching How To Make Soap

Cheaper Than Store-bought Soap

Long before I started making my own soap, I knew that the cold process method would be the most authentic and difficult to master. But once I got the hang of it I quickly realized the total cost to make several months worth of soap bars was far cheaper than buying the chemical cocktails from the store.

Since then I’ve created, photographed, and videoed many homemade soaps. And even built my own soap calculator, complete with a formulation guide to help you create on your own recipes.

examples of my cold process soap for beginners

Basic Supplies & Equipment

Once I learned cold process I quickly realized that because you have total control over what goes into your soap recipes, you can avoid using any ingredients that do not suit your skin.

a collection of soap making ingredients

The full rundown of items that I recommend can be found at wholesale soap supplies and equipment. Some of them you will have already, some you can make and some you will need to purchase.

These items are not very expensive, so your setup costs to start making soap at home will not break the bank!

These items are not very expensive, so your setup costs to start making soap at home will not break the bank! To begin with, here’s a simple list of what’s required.

The ingredients specified below or another cold process recipe
A mold
Cutter and box
Hand whisk or basic stick blender
2 candy thermometers or a lazer temperature gun
Digital kitchen scales (grams)
Safety glasses and long rubber gloves
PH strips for safely testing acidity
Large stainless steel pan
Large plastic /glass jug or plastic bucket.
Plastic spatula
An old towel

Safety Before You Begin With Cold Process

A lot of folks express concern around the cold process soap making procedure, in particular, the dangers of working with Lye, and yes you do want to take some precautions whenever you handle it. Lye is the most common alkali used for making soap. Its official name is sodium hydroxide (NaOH) and is also known widely as caustic soda.

Having said that, all that’s required is a bit of common-sense, which you already have otherwise you would not be reading through this guide!

Important things to remember when working with Lye

What is lye?
Lye (Sodium Hydroxide/Caustic Soda )
  1. All of the recipes on Savvyhomemade allow 5% superfatting. This ensures correct saponification (the chemical reaction that creates soap) making sure there is zero free caustic alkali remaining and a good ph balance is achieved. As long as you have measured your ingredients correctly you have nothing to worry about. To be sure always test it using a ph strip to make sure it is somewhere between 7-10.
  2. Make sure you are making your soap in a well-ventilated area. Put on protective eyewear, mask, apron, and long rubber gloves to protect the eyes and skin. Should you get some on your skin rinse with vinegar before washing it off using water.
  3. Once you add the Lye to water it creates a small chemical reaction, some choking fumes will rise from your bowl. This is the area that concerns most people, but all you need to do is keep your face away from these fumes while you stir the mixture and try to not breathe them in. You could use a mask here if you want. I wrap a scarf around my nose and mouth and that’s probably sufficient, as the fumes only last a few moments.
  4. Never leave your soap mixture unattended, this is a big no-no, especially if you have children or pets in your home.
  5. When cleaning your soap pot, allow the mixture to solidify and scrape it into a bag to be sealed and disposed of. Keep your gloves on when cleaning and add some vinegar to your washing up water to help thoroughly clean your utensils.
  6. Don’t be tempted to use your soap until you are sure that it has cured, if in doubt test it with a ph strip to make sure it is somewhere between 7-10. If you made a mistake and after 4 weeks it measures above 10 don’t just throw it away as you can rebatch it.

For more reading on this subject take a look at my in-depth guide on why we use Lye which is definitely worth a read.

Adjusting The Volume Of Your Scent

Add your essential oil to soap batter

You can adjust the scent volume here up to 3% of all the oils and water added together. Anything over 3% would be very strong depending on the oils you are using, so I recommend starting at 2%.

The recipe below is a good old fashioned soap that makes a great base for any fragrance, colorants, and exfoliates that you may wish to add. If making your own recipe, remember to use the lye calculator and formulation guide to get the correct volumes.

Let’s move on and take a look at the basic soap recipe, ingredients and method.

soap making for beginners

How To Make Cold Process Soap

This cold process soap is one of my favorites, it’s made with simple ingredients to make a great creamy natural bar. It holds a good hardness and lathers up very well.
5 from 2 votes
Print Rate Pin
Prep Time: 30 minutes
Active Time: 30 minutes
Curing Time: 28 days
Total Time: 28 days 1 hour
Difficulty Level: Intermediate
Yield (adjustable): 12 Bars (approx)
Author: Angela Wills
Disclosure: The ingredient and equipment links below are affiliate links, please read my affiliate policy here.

Ingredients

Instructions

  • Gather and measure the ingredients shown above or from one of my other cold process recipes.
    You will need to measure your ingredients carefully, Do Not try to guess or use cup sizes as when you make soap it needs the correct mixture to complete the saponification process.
    Use either grams or ounces, do not mix the two. I prefer grams as I find it much more accurate if you need to convert ounces into grams for any reason simply multiply by 28.35. More information on measuring, easy conversion and other cosmetic tips can be found here.
    cold process soap making ingredients
  • Prepare a mold. If you don't have a specific soap mold, then any good size container will do. Sturdy plastic containers that still have enough give to ease the soap out make the best containers because you don't have to line them.
    Recently I've been using silicon molds as it's so much easier to remove the soap. A quick grease round with a little solid oil from the recipe and they're good to go.
    Glass, wood, ceramic or cardboard all lined with freezer/butcher paper will also make suitable molds. Avoid using any metal molds unless you can be sure they are stainless steel.
    preparing a cold process soap mold
  • Now its time to mix the lye with water, and as I already mentioned above, this is a chemical reaction so we need to take some precautions.
    Make sure you are making the soap in a well-ventilated area. Put on protective eyewear, mask, apron, and long rubber gloves. Pour the mineral water into a large glass/sturdy plastic jug or plastic bucket. 
    Now, slowly, pour the lye (caustic soda), using a plastic spatula to stir until dissolved. The water will start to heat when it reacts with the lye, it will need to cool until it reaches the required temperature (see specific recipe).
    Combine your caustic soda to your water, making sure it's in a heatproof jug.
  • In a large stainless steel or enamel pan, gently melt any oils or waxes over a low heat. (this does not include essential or fragrance oils). Use two candy thermometers place one in the caustic soda mix and one in the oil mix.
    Update; I now use an infrared thermometer gun, it's much easier.
    When both mixtures reach an equal temperature begin to pour the mixture and stir the lye into the oil, DO THIS SLOWLY, and remember that you should always add lye to other materials, not the other way around, pouring a liquid into lye crystals can cause it to splash and can burn your skin.
    I recommend combining at a balanced temperature of between 120F and 140F (49C-60C).
    Caution: Be very careful handling and mixing the lye. It is extremely caustic and can burn if it gets and stays on the skin. If at any point you spill or splash lye or caustic batter onto your skin, wash it off with lots of water right away.
    You can also use some kind of vinegar or lemon juice to calm the burning and wash away the lye, then rinse thoroughly with water. Remember that lye is alkaline, not an acid, and so a gentle acid should help to neutralize the lye. If this doesn't help, seek advice from a medical professional as soon as possible.
    Once your temperatures are balanced, pour your lye into your oils.
  • Using a stick blender begin carefully stirring your mixture for several minutes, slowly at first without switching the blender on.
    Using a handheld food processor, whisk the soap mixture in bursts until trace.
  • Reaching The 'Trace' Stage: Then give your mixture a few short 3 second bursts, stirring between each burst until the mixture thickens slightly and looks a little like thick custard.
    This is called "trace" and it's a sign that your soap is turning out well. By dipping your spatula or spoon into the mixture and dribbling a small amount back into the mix. It should leave a light "trace" behind (like a small mound of batter that takes a few seconds to blend back within the mixture.) This is when you know you've reached the "trace" stage.
    Or by hand which will take a little longer, maybe up to an hour but with consistent slow even stirring with a hand whisk you will eventually reach the trace stage.
    And now is usually the time to add any extras like flowers, fragrance, essential oils, colors or textures into your recipe. But check the individual recipe to be sure. There are so many things that you can add, check out some of these interesting soap making ingredients and textures.
    Step 4: You can see here what trace looks like
  • Pour your soap into the mold and smooth out using a spatula.
    Once you have reached trace, pour the mixture into your chosen mould, working quickly but carefully.
  • Place a piece of cardboard over the top of it.
    I find it's helpful to cover the top of your soap with a purpose cut peice of cardboard.
  • Wrap an old towel around the whole thing to keep the heat in.
    Insulated your mold with a towel, or place in a relatively warm area of the house.
  • Allow your soap to set for 24 hours in a warm place until the soap has hardened. Don't be too alarmed if you take a quick peek at your soap and it looks translucent, this is called the gel stage and is perfectly natural. When it has hardened (usually around 24 hrs), remove from the mold and allow it to air for a few hours.
    Leave for a minimum of 24 hours, then you can remove your soap from the mold.
  • As a general rule, it should be about the consistency of hard cheese before you cut it. The soap will still be caustic at this point so I would recommend still handling it with gloves for the first 48 hours.
    Cut it into blocks, for this you can simply cut by hand for a more rugged look.
    You can cut all of your soap right away, or you can leave it in a block.
  • Or use your soap cutting box for something more symmetrical.
    Next cover/line a cooling rack, tray or box with a cloth and stand the bars upright without touching each other so the air can circulate. Store them in a dry ventilated place turning them each day in the first week and then every other day thereafter for 4 weeks. This time continues the curing process ensuring that all of the lye has been neutralized and water evaporated.
    During this time you may find a fine dust on your soap, this is soda ash and can be scraped off before use.
    You can use a soap cutting box to get portions right.
  • All of the cold process recipes on Savvyhomemade allow 5% superfatting. This ensures correct saponification (the reaction that creates soap) making sure there is zero free caustic alkali remaining and a good ph balance is achieved.
    As long as you have measured your ingredients correctly you have nothing to worry about. To be sure always test soap using a ph strip to make sure it is somewhere between 7-10.
    Basic homemade soap that leaves skin feeling soft and smooth

Notes

Tips

  • To get a good idea of the size of mold needed add together the oils and water in the recipe and then fill a mold with that amount of water.
  • The best way to line your mold when using the freezer/butcher paper is to cut two strips, one to go across the width of your box and the other going across the length. Leave enough on the paper to fold over the edges and secure with tape.
  • I make a lot of soap and I found a great little tip that helped out. This was to buy a simple, cheap plastic cutlery bin from Amazon. As you can see in the photo it’s a great half-moon shape and was perfect for the goats milk soap. It also has a little give in it to help ease the soap out. It makes around 10 large bars per compartment… Perfect for making multiple batches!

Possible Problems

  • If your soap does not harden or just hasn’t turned out quite as well as you expected it to, or maybe you forgot to add something. Then you may be able to rebatch it by melting it down and adding any missing, or miss calculated ingredients.
  • If your batch is too lye heavy, making it very brittle and crumbly or if your lye and oils have separated (you will notice a layer of liquid on the top or underneath the soap) I would encourage you to discard it.
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Final Thoughts

So there you have it, the complete guide on how to make soap using cold process. It’s one of four different soap making methods, I hope you enjoy this craft as much as I do!

If you decide to have a go at making soap, I would love to see some photos and hear how you got on. Others have sent photos, you can see them here, so feel free to post yours in the comments below or using the contact form. And ask any questions if you need some help.

Angela Wills

About Angela Wills

SavvyHomemade is a true passion for me and my family, its where we've been busy sharing inspirational DIY craft ideas since 2008! With over 30 years of handcrafting and creative experience, the dream is that this information will make life a little easier for others whilst also doing a little towards protecting our planet. More About Angela Wills »

33 thoughts on “How To Make Soap Using Cold Process”

Discussion (33 Comments)

    • Hi Paula,

      Lots of things can be used as exfoliators in soap. My favourite is poppy seeds, although you can use anything that’s coarse and doesn’t dissolve in liquid soap batter. Cranberry seeds are a nice alternative.

      Hope this helps!

      Reply
  1. Can you substitute the shortening with cocoa butter or shea butter. I have never used shortening before. If so what would the measurement be.

    Reply
    • Hi JoEllen,

      You absolutely can! However, I would run it through a sap calculator so you can adjust the amount of lye as necessary.

      Hope this helps!

      Reply
      • I would also like to substitute the shortening as I can’t find any without palm oil in it. I have found the lye calculator, in order for the soap to have the right texture presumably the substitute also needs to be solid and a similar quantity? Also will whatever you choose affect the ability of the soap to lather? I was considering solid coconut oil

        Reply
        • Hi Ann,

          Yes, I would definitely recommend using a solid that has a similar texture to the ingredient you wish to substitute it for. However, this won’t necessarily produce a similar result. It is, however, a good starting point. Nevertheless, you ask a very good question here, regarding the effect substitution can have on the overall quality and properties of soap. Many people think substituting is an easy thing to do, but it does take some experimentation. Props to you!

          While you can simply up the coconut oil as you suggest, the lack of shortening will make the bar feel less creamy. I don’t think it will lather any less, but the lack of creaminess is a deal-breaker for me. Have you considered using cosmetic butter? It’ll make your skin feel heavenly! The reason I use shortening in this recipe instead of a cosmetic butter is simply that it’s so much cheaper and for a new soap maker who may make mistakes, which can get costly pretty quick.

          But if you feel up to it (which I have a feeling you are), I would suggest substituting 100g of the shortening for Shea Butter, then the rest can be substituted for more coconut oil (so 280g more). Be sure to run it through the lye calculator again before deciding how much lye and water you’ll need. If you don’t feel ready to use shea butter yet, just substitute it all for coconut. Maybe you can use Shea in your next batch!

          I’m also glad you’ve mentioned that shortening more often than not has palm oil in it. I myself am moving towards eliminating all forms of palm oil from my blog and my life in general, so I will definitely be taking another look at this recipe in the near future.

          I hope this helps and good luck with your soap making!

          Reply
  2. Hi Angela. Thank you very much for this recipe, I’m a beginner and all of the steps are provided are very helpful. I was wondering, for the basic soap recipe, what is the temperature at which one will need to mix the lye into the oil?

    Reply
    • Hi Melissa!

      Excellent question! I generally recommend pouring at a balanced temperature of between 120F and 140F (roughly 49C-60C). It’s best not to pour hotter than 140F, as I find you can end up with some unsightly soda ash on the surface of your soaps. I’ve amended this page to make it a little clearer for everyone going forward. Hope this helps!

      Reply
  3. Hey Angela, such a great recipe you had shared. I had no idea that i can make soap at home. Thanks for sharing this article. I didn’t make it before. Those soaps are looking perfect. Your tips will help me to make that correctly. Keep sharing this type of helpful articles. 🙂

    Reply
  4. Hello,
    I would like to thank you, as you are doing a great job for the people. To me its like a social welfare!!
    Anyway, I need Clothes cleaning soap making formula from you. Can you help me plz???

    Thanks to You

    Reply
    • Hi Zahir, thank you for your kind words!

      As for laundry detergent, unfortunately, I’ve never made it before. But it does sound like an interesting craft. Though I doubt it would be a soap as such. Most likely it will a combination of detergent agents, surfactants and other ingredients along these lines. I’ll look into it and maybe I can do a DIY laundry detergent post or video in the near future!

      Reply
    • I would like to make my own soap but I am so confused about it? Is it really hard and complicated as the book is saying? What is your suggestion if I want to make a soap with soft end result? Can we replace any of the oil above with rapeseed oil? and i am so happy for your kind.i wish all the best

      Reply
      • Hi ELias,

        Making soap for the first time can be quite confusing, so that’s totally normal. However, if it is your first time making soap, then I strongly recommend to just follow the recipe exactly how it’s written. Trying to substitute and redesign soaps so they have different qualities is not something I recommend for a beginner. This recipe should produce a lovely soap, so don’t worry about it too much. Once you actually start making soap, you’ll soon build to skills to be able to use a lye calculator and substitute ingredients happily.

        P.S. It is very important not to substitute ingredients like for like when you’re soap making. You absolutely must use a lye calculator to ensure you’re using enough lye and water. Otherwise you may not get soap out of your recipe, or worse you could end up with too much lye and your soaps can burn your skin.

        Reply
  5. Absolutely beautiful!! I am newer to soap-making, do you know if this would work well in a soap mold? I have just purchased some and im hoping to make some cute soap gifts for fall. I’ll probably make it either way, but would love to use my new molds if you think it would work! Thanks for sharing this! 🙂 I’m loving your site.

    Reply
    • Hi Amanda, this will work with just about any soap mold, there are literally hundreds of soap molds available to choose from. I have a page listing all of the supplies and tools required for making a basic soap recipe, check it out here.

      Reply
  6. Hi, I’m new to soap making, I don’t quite understand the super fat ting, but have you allowed for any in this recipe ???

    Reply
    • Hi Ganor,
      All of my soap recipes have a superfat level, most of them like this one have around 5%. Any extra oil left in the soap and not attacked by the lye is called a ‘superfat.’
      Simply put this means that once the soap is made it still has around 5% oils left in it. This ensures that all of the lye has been used making the soap safe. It also gives a nice level of moisturiser.
      Here’s a more detailed explaination for you savvyhomemade soap calculator

      Reply
  7. I have been wanting to make soap for over a year, and I am still a little hesitant to work with lye. I have a friend who has been making soap for years already. She offered to help me. I would like to use your recipe, but I don’t have a special thermometer. Can I use an old personal thermometer?

    Reply
    • Hi Bethany
      I don’t line the cutlery tray, I just give a quick grease round with a little solid oil from the recipe. Sometimes it can be a little tricky to get them out, but as long as there’s a little give in the tray just persevere and you will be able to ease the soap out. That’s not to say that you cant line it but the finish might not be as smooth.

      Reply
  8. I have been making this recipe minus the fragrance for a very long time. It is by far the best soap ever. I have also added coffee grounds to it from time to time. Great soap!

    Reply
  9. I live in the tropics so is it better to make soap using lye in summer average daily temp is 30celcius/80% humidity or in our winter average daily temp is 25celcius & very low humidity

    Reply
    • Hi Lorna

      I’ve not tried making soap in such humid conditions but it probably wouldn’t be a problem and I guess it wouldn’t hurt to try. Having said that if I had the choice, I would make it in the winter months 😉

      Sorry I couldn’t be of more help but I hope it all goes well for you… let me know how you get on!

      Angela

      Reply
  10. I am glad you are recommending to use a mask and googles. I think that can not be stressed enough. I have had lye splashed on myself and it is not a pleasant experience. Now, I am always sure to wear long sleeves, a high neck line, long pants, gloves, googles and a mask. The fumes from the lye can cause damage to your lungs and can burn your eyes if splashed, so a mask and googles are imperative. After that is said, it is a safe process if you take precautions and are careful with what you are doing. I have enjoyed making soap for 15 years.

    Reply
  11. Hi,

    I would like to make my own soap but I am so confused about it? Is it really hard and complicated as the book is saying? What is your suggestion if I want to make a soap with soft end result? Can we replace any of the oil above with rapeseed oil?

    Reply
  12. Hi Christine,
    I haven’t tried it with red palm oil, so I can’t say for sure that it would work as well.
    I guess it would change the color and it depends on if you are in the mood to do a little experimenting, I would 🙂
    If you do try it, make sure you use a lye calculator to check your recipe, and could you please let us know how it goes.

    Reply

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