How to Make Cold Process Soap from Scratch Using Lye (Modern Cold Process Soap Tutorial & Recipes)
Making cold process soap from scratch doesn’t have to be hard or scary. You can learn how to make homemade soap with lye, or old fashioned lye soap, using modern soap making methods, techniques and homemade soap recipes with this beginning soapmakers guide. Keep reading to learn how you can get started with this exciting new hobby or explore a new career making path with this cold process soapmaking tutorial, soapmaking tips and tricks and beginner cold process soap recipes.
Getting Started in Cold Process Soap Making
Ever wanted to learn how to make cold process soap but aren’t quite sure where to begin? In this revised cold process soapmaking tutorial I fill you in on the basics you need to make cold process soap from scratch along with the equipment, tools and ingredients necessary to get started in the fabulous world of soapmaking!
While soapmaking is not initially what one would consider a “cheap” craft or hobby to get started in – there’s a reason why homemade soap bars cost between $1-$2 an ounce! – it can be highly rewarding to those it interests and extremely beneficial for those who suffer from problem skin. The right ingredients can help with issues like acne and eczema and everything in between.
There are a lot of ways to save money in the beginning, however, while you’re still getting your feet wet. It can be as simple as starting with ingredients like bacon fat leftover from breakfasts to using a lined shoe box as a soap mold. Most importantly though is to really research the topic before diving in. Doing so can prevent failed batches and lead to the excitement of unmolding your very first successful loaf of soap! Once you’re there you can save by purchasing ingredients in bulk and delve into experimenting with soapmaking.
There are a few key things to know before getting started making soap. One of those things is that to make cold process soap from scratch is you have to work with lye.
Without lye there is no soap.
The scariest thing for me when I first started making soap was working with lye. Lye – also known as sodium hydroxide – is a necessary part of making homemade soaps. Without lye, there simply is no soap. You must have a fat – your soapmaking oils and butters – and an alkali – sodium hydroxide – to make soap. When combined they go through a chemical reaction called saponification. During this process, the lye is used to chemically change the fats into soap. If done correctly, there is never any lye left in the resulting soap.
The only way to avoid working with lye is to buy pre-made bases. However, as I quickly discovered, this limited the final outcome of the soaps I made. If you’re looking for soaps that have specific properties, the best way to get them is to design exactly the kind of soap you want by including ingredients with the properties you want into your cold process soap recipe.
Yes, lye is a little scary. However, once I finally dove in and made cold process soaps for the first time, I realized that it wasn’t nearly as terrifying as I thought it would be. I’ve found that tutorials on soapmaking tend to have you be overly cautious about working with lye so it seems frightening. The truth of the matter is however, it isn’t frightening as long as you have sound knowledge of what you’re doing going in, and you take simply safety precautions – just like in high school chemistry class. So purchase some goggles, some gloves and for kicks you can also go with a fancy new rockabilly apron just so you have some great photos to share on your social media.
Your goggles and gloves can be purchased at your local hardware store. This is also likely where you’ll find the lye you need to get started. Many hardware stores have jacked their prices on lye double what they were a few years ago AND started keeping it behind the counter. This is due the rise in methamphetamine use as lye is one of the ingredients used to make meth. Naturally this can make sourcing lye a bit discouraging especially if your hardware store has chosen not to carry it at all.
The most common brand of lye I’ve found locally, since grocery stores stopped carrying Red Devil Lye, is Roebic Heavy Duty Crystal Drain Opener. It’s sold in 2 lb. Containers and contains 100% lye (sodium hydroxide, caustic soda.) There are other brands out there as well and they will suit fine as long as they are 99% or more pure including CornStar, Red Crown and Rooto Corp. Another alternative would be to hunt down your local soapmakers – I networked with local soapmakers at my farmer’s market – and see if they have any lye they can sell you just to get started or can tell you where they source lye locally.
Additionally, you can also purchase lye at various places online from chemical supply companies, soapmaking suppliers and Amazon. I buy my lye from a local chemical supply company. While it’s much cheaper for me to purchase lye this way it does require buying in bulk. The smallest size of sodium hydroxide pellets they offer is 55lb. However, it costs less than $40 and I can pick it up at their warehouse. Unless you know you’ll be going crazy making soap 24/7 though, I recommend paying a little more and starting out with a much smaller quantity.
Now that you’ve sourced your lye, suited up with your goggles, gloves and that rockin’ apron, you’ll need a few housewares. It’s likely you already have a few of these things in your home so you’re not splurging all your funds on equipment. Because quite honestly you’ll want to splurge on the ingredients going into your soap. That’s where all the fun is at. If you’re off to a running start and plan to make enough soap to wrap around the moon and back, then you might want to buy all new equipment to keep your kitchen utensils and pots for actual food separate from the strictly soapmaking equipment. But it’s not necessary to never use your soap pot for cooking spaghetti in again. Just wash it really well. Wash it again to ensure there’s no residue and you’re good to go.
You can save some money of course by checking out second hand stores if necessary or simply desired. Or if you have the green light from your significant other to go crazy, then I recommend you just go crazy.
Cold process soapmaking equipment you’ll need to get started.
A digital kitchen scale that weighs in grams and ounces and can handle some more significant weight. I have used a Baker’s Math scale for years and highly recommend it over say a shipping scale from an office supply store as it will stay more accurate over time and last much longer.
A stainless steel pot for mixing your soap. You NEVER want to use aluminum ANYTHING to make soap as this does some pretty crazy chemistry of its own when it reacts with lye. And it’s not the chemistry we want for soapmaking. It’s also pretty dangerous. Therefore if you aren’t 100% certain your pot isn’t aluminum, then buy one that you know is most definitely not.
A thermometer so you can accurately judge the temperature of your lye-water and oils before you mix them together.
You’ll also need a stick blender/hand blender/immersion blender. It’s called many things, but it’s basically the same tool. This takes the hardest physical part of soapmaking – the mixing – out of the equation. As a result your soap will trace faster, meaning less time you have to stand around mixing, and it also helps to ensure an evenly mixed batch of soap. I wouldn’t say any one brand is better than another as I’ve had cheap stick blenders last for ages and do just as well as the more expensive ones.
Pitchers and measuring cups! You’ll need a heat safe pitcher or container to mix your lye-water in as well as to weigh out ingredients. (It is now recommended not to use glass Pyrex measuring cups to mix the lye-water in as with the newer Pyrex it can etch the glass over time and inevitably lead to breakage.) It’s good practice is to inspect your containers regularly for any signs of wear or cracking as well as to mix your lye-water in a sink or outside in case a container does break in the process.
You’ll also want to have some handy dandy utensils like large mixing spoons and a spatula. I use a long plastic spoon – like the wooden ones but plastic – to mix my lye water. I use a heavy duty metal spoon to scoop out semi-solid oils and butters, and a spatula to get all of the soap out of the pot into the mold. Occasionally I even use a knife or a grater for hard oils and butters to get them down to size. You’ll find what works best for you and likely you already have all of these things hiding in drawers in your kitchen.
Finally you will need a mold for your soap. You don’t need to spend a lot of money on a fancy soapmaking mold. Your mold could be as simple as a cardboard box or a tupperware container that has been lined with a trash bag. Alternately you could purchase a silicone loaf soap mold or a silicone loaf pan – the same kind used in baking – or you can easily make your own wooden loaf soap mold with just a few materials from a hardware store for next to nothing.
I’ve been using wooden loaf soap molds that my dad made me for well over a decade now. I like the wooden molds because they are practically indestructible. Most of my homemade soap recipes I develop contain 36 oz. in oils and fit perfectly inside these molds. If you’d like to make your own wooden loaf molds you can find the dimensions for this mold along with instructions for making your own here.
Keep in mind however that using a wooden soap mold does require some preparation before use. While you can pour your soap directly into a silicone mold, you must line a wooden soap mold. (The same goes for using a tupperware container or a cardboard box.) However, for round soaps you can use an empty Pringles can and simply peel the paper container off your soap once it’s gone through the saponification process.
Not lining your wooden soap mold will cause your soap will get stuck and result in a lot of unnecessary frustration. When I first started making soap, I used to cut parchment paper to line my molds. Basically you fold the paper in a way that is similar to wrapping a present but with an open top. I’ve also seen contact paper used in the same way as demonstrated in this tutorial from Inner Earth Soaps blog. However, I found that both parchment paper and contact paper can get expensive over time. And I also found the process for lining my soap molds this to be overly tedious and time consuming. Because of this, and due to the stiffness and occasional pain in my hands from the fibro, I use thin, commercial office trash bags to line my molds. (These are rather inexpensive to purchase at places like Sam’s Club and Costco. So if you lean towards more practical than perfect and don’t mind a few minor creases on the sides and bottom of your soap, then this method may be the one for you. Plus, once you’ve unmolded your soap, the trash bag can still be used as an actual trash bag.
To line my wooden soap mold using a trash bag, I simply unfold the bag – but don’t open it – press it into the mold and then tape the outer edges with masking tape where the bag folds over the outside of the mold to keep it in place. This method is gentle on hands and super quick especially if you are lining multiple soap molds at once. Of course, how you choose to line your molds is personal preference. I recommend doing whatever works best for you. Once your soap has set you simply lift the soap from the mold and peel off the liner, cut into bars and allow to cure. And, if you used a fragrance in your soap, you know have a scented trash bag for the bathroom!
Determining the amount of soap needed for your mold.
Have a homemade soap recipe you’d like to try but aren’t sure if it will fit into your mold? No worries. There’s a simple formula for determining the weight of the soapmaking oils needed for your mold. About.com has a formula and instructions for calculating the amount of soap needed to fill a mold here. They give the basic math equations for determining the correct soap recipe size for standard square or traditional molds, round or tube molds and odd or irregularly shaped molds. You can then re-size your homemade soap recipe to fit into the mold you are using.
A little about cold process soapmaking ingredients.
Now that you have your soapmaking equipment, it’s time to focus on the ingredients for your homemade soap recipe.
For your first attempt at making cold process soap I recommend using a tried and true soap recipe rather than creating your own. It is helpful to know some of the basic chemistry about your ingredients so that you can create your own homemade soap recipes in the future. Your fats – or soapmaking oils and butters – will very much determine what properties your soap will have. For example, three of the traditionally popular soapmaking oils, especially for beginners, are olive oil, coconut oil, and palm oil. Olive oil helps to create a moisturizing bar with a stable lather; coconut oil produces a hard, cleansing bar with a fluffy lather; and palm oil makes for a hard bar with a stable lather. Each of these oils has its own SAP (or saponification) value which determines how much lye should be used in the soap recipe for saponification to occur in such a way that it makes soap. Too much lye and you have an unusable bar of soap. Not enough and you could end up with a really soft soap with excess oil.
A great source for learning more about the saponification process and the properties of various soapmaking fats & oils is Susan Miller Cavitch’s book, The Soapmaker’s Companion. Her book also contains a great troubleshooting section to help you figure out what might have gone wrong with a soap recipe as well as a nice collection of her own recipes.
(For more on this as well as information on how to make your own homemade soap recipes and how to use a lye calculator be sure to check out this article on how to make your own cold process soap recipe.)
How to make cold process soap.
Following are your basic step-by-step cold process soapmaking instructions for how to make cold process soap from scratch. Keep in mind these steps aren’t always set in stone and temperatures used in soapmaking can vary based on the ingredients you’ve chosen for your homemade soap recipe.
1. Begin by preparing your soap mold so that it is ready when your soap is ready to be mixed and poured. For some recipes you will also also need to cut out a piece of cardboard to cover the top of your mold. The cardboard will be used to help insulate your soap after it is made, assuming insulating your soaps is needed for the gel phase.
2. Once your mold is prepared measure out the amount of distilled water (or other liquid) called for in your soap recipe in fluid ounces. (Or whatever measurement you are using for your recipe.)
3. Pour your distilled water in a non-aluminum container. This may be a sturdy plastic pitcher or a glass Pyrex measuring cup. (If using glass be aware that lye-water can etch glass and so it should be check periodically for cracks or excessive etching.)
4. Next, while donning your safety gear, weigh out the lye using a digital scale. Place the container you’re using to measure the lye onto the scale, press tare to zero it out, then slowly pour the lye onto the scale until you reach the amount needed.
Now, in a well ventilated area, slowly pour your lye into the container of distilled water. (You never want to pour the water into the lye as it could result in a not so pleasant volcano effect.) Stir your lye into the water with a plastic or wooden spoon until it dissolves thoroughly. Now set the lye-water aside to cool. If you’re mixing the lye inside, keep it on the stove with the exhaust fan turned on and step away. Or allow it to cool outside to avoid the nasty fumes. Be sure there are no children or animals underfoot who could get hurt.
It’s also important to note that lye-water gets VERY hot and can cause chemical burns. If you are splashed with the lye-water thoroughly flush the affected area with cold water. Then use vinegar to clean up any spills on hard surface areas.
5. While the lye is cooling, use the digital scale to weigh out the soapmaking oils, butters and waxes as well as any other ingredients. After weighing each of my soapmaking ingredients I combine them into a large stainless steel pot then place them on the stove over medium heat. You can also melt your oils separately in canning jars within a water bath. This works well if you are planning to soap closer to room temperature.
Begin by weighing each of your soapmaking oils and butters individually. Set the container you are using to weigh your oils onto the scale then hit tare to zero out the weight. Slowly add your first oil to the container until you’ve reached the weight the recipe calls for.
Repeat this process for all oils and fats in your recipe. I usually start with the solids first so I am adding the liquids to the pot last, but that is just personal preference.
Once all the soapmaking oils are combined in your pot, place on the stovetop at medium heat until the oils have all melted. Stir the oils and remove from heat, then set the pot of soapmaking oils aside to cool.
6. Once your lye-water and soapmaking oils have cooled, you are ready to make soap! I find that most soap recipes work best when the lye-water and oils have cooled to between 90°F-100°F. However, the temperature of the oils can vary depending on the ingredients you are using or what temperatures the soap recipes you are using calls for. In addition, your oils should not be hotter than the lye-water. If you aren’t sure how a recipe will react at higher temps, then it’s safe to hazard a guess and soap between 90°F-100°F. (Refer to The Soapmaker’s Companion for information on why temperatures matter.) With your handy stick blender ready to go, very slowly pour the lye-water into the oils.
7. Begin stirring the soap ingredients with the stick blender on low. As the lye and oils begin to incorporate, you can switch to a higher speed. Mix thoroughly, moving the blender all through the entirety of the soap ingredients so it’s evenly combined. You do not want to hold the stick blender in just one spot while you are mixing.
Continue to stir the soap until you reach what is known as trace. You will know your soap has traced when you can pull the blender through the soap and it leaves a line behind it. In addition, if you lift some of the soap up with the blender and then drop it onto the surface of the soap, the soap should be able to support that drop.
Should you not reach trace, within 15 minutes, you can rest for about 15 minutes, then start mixing again. Some oils used in soapmaking are slower to trace. Virgin olive oil, for example, can take a much longer time to trace than other oils unless it is mixed with other oils whose properties promote a quick trace. (Alternately, pomace olive oil is known for a much quicker trace.)
8. If you are using any additives for your soap such as fragrance, herbs or colorants, you will want to add these to your soap once has reached a light trace. A light trace just barely leaves a trail when running the stick blender through it. (Alternately a heavier trace is much thicker and looks a little like pudding or custard.)
After adding these additional ingredients use the stick blender to thoroughly mix them into the soap so they are evenly incorporated throughout the soap. This is especially important for fragrance oils and essential oils as you do not want any “hot spots” in your soap. (Generally fragrance oils account for 3-6% of your soap and essential oils for 1-3%; but be sure to follow manufacturer’s recommendations if they are available.)
Tip: When choosing a fragrance oil or essential oil for your soap recipe, keep in mind that some fragrances and essential oils can accelerate trace or cause soap to seize. Your supplier should be able to provide information on how their fragrances perform in cold process soap.
Once your additives have been thoroughly incorporated, you’re ready to pour your soap into its mold!
9. Slowly pour your soap into the prepared mold. You can use a spatula to help you get all of the soap out of the pot. Once you’ve poured all of the soap into the mold, you may find it helpful to drop the mold onto the counter several times to help remove any air bubbles.
If your soap needs to be insulated cover the mold with a piece of cardboard cut to fit. Then cover the mold with a blanket or towel. This ensures that your soap goes through what is known as gel phase. However, soap doesn’t necessarily have to go through gel phase to make a successful batch of soap. Some soapmakers choose to actually prevent gel phase and will freeze their soap after pouring it into the mold. Soapqueen.com has some insightful information on the gel phase here.
If you check your soap and notice it is starting to crack on the top your soap is overheating. In this case you will want to uncover the mold completely.
Once your soap has been in the mold for 24 hours it is ready to be unmolded.
10. Unmold your soap and, unless it is still soft, go ahead and cut it into bars. (You find information on how to make a simple loaf soap cutting guide here.) I generally discount the amount of water used so that my soap can immediately be cut into bars. If you find that your soap is on the soft side, simply wait another day or two before unmolding and/or cutting your soap loaf into bars.
Now place your soaps in a safe, dry location and allow your soap to complete the saponification process – this typically occurs within a day or two – and allow your soap to cure fully. This generally takes a period of 4-6 weeks.
If you’re setting your soap to dry on a flat surface, be sure to set it on top of parchment or freezer paper to keep any oils or moisture from seeping out of the soap into the surface of your drying space. You can also dry your soaps on a rack.
Properly curing your soap will not only help your soap last longer, but it also makes the soap milder on skin and gives you a better lather.
Once the soap has cured you can then package it to share with your friends and family! If you are planning to sell your homemade soaps, you’ll need to include the weight of the soap on each bar.
I like to use Bakers & Chefs 12″ x 3000ft. Foodservice Film to wrap my cured homemade soaps. It’s not only inexpensive for the quantity but it sticks much better than regular plastic wrap making it a both a smart and simple choice for wrapping both cold process soaps and melt and pour glycerin soaps and giving them a more professional look if you are selling your homemade soaps. You’ll find that the 12″ size is perfect for most standard size bars of soap. While it’s best to let cold process soaps to “breathe,” I’ve never had issues with using food service film on my cold process soaps. However, smart alternatives include a simple cigar band or wrapping in paper or fabric.
Keep in mind if you are selling your soaps you must have the weight of the soap on each bar. And unless you’re labeling your soaps as a drug per FDA guidelines you don’t want to make any medical claims about your homemade soaps.
Still have cold process soapmaking questions?
Not everyone has a successful soapmaking experience the first go around. So if you’re still cautious after all of your research, then I recommend finding a friend who makes soap to teach you the process or try watcing a few YouTube videos on soapmaking. (My first batch was made well before social media and youtube came along and was a complete failure as the instructions I had didn’t indicate to weigh the oils and I thought mixing by hand would be sufficient. It was an expensive mistake as I was using grocery store olive oil but luckily I didn’t giv up.)
Beginner cold process soap recipes.
Now that you know how to make cold process soap you’re ready to try your knowledge into actual practice. Following are a few of my own beginner cold process soap recipes to get you started.
Beginner Cold Process Soap Recipe: Try this easy beginner cold process soap recipe to get you started in soapmaking. This easy cold process soap recipe requires just three inexpensive soapmaking oils that can be sourced at most grocery stores. I also offer several substitutions that you can use for the main ingredient that won’t require you to recalculate the amount of lye needed.
Lemon & Poppy Seed Cold Process Soap Recipe: This simple homemade nut free soap recipe contains zero nut oils so even those with nut allergies can enjoy this classically scented lemon poppyseed soap. While coconut oil traditionally boosts lather in homemade cold process soap recipes, this nut free soap recipe instead uses palm kernel flakes which has similar lather boosting properties. In addition it also incorporates less costly ingredients for those who are soaping on a budget.
Coconut Oil Facial Soap Recipe: This coconut oil facial soap recipe for acne prone skin combines ingredients known for their acne fighting properties to help keep skin acne free! Like the name implies, this coconut oil facial soap recipe is formulated using refined coconut oil at 100% with a 20% superfat so it doesn’t over dry skin. Neem oil, sea buckthorn oil and a blend of essential oils are also included in this natural homemade soap recipe to help kick acne to the curb and keep it away. This coconut oil facial soap recipe also makes a great body soap for oily skin.
Traditional Castile Soap Recipe: This traditional Castile soap recipe is scented for spring with natural basil, lemongrass and rosemary essential oils and is made using 100% olive oil.
Homemade Garden Mint Soap Recipe: This homemade gardener’s soap recipe is perfect for a gardener. Not only does it smell amazing but it’s rich, thick lather and combination of exfoliants really help to scrub and wash away caked on dirt and grime. It’s also great for messy artists and crafters as well as mechanics!
Vanilla & Fig Shaving Soap Recipe: This simple homemade shaving soap recipe is great for beginner soapmakers still getting their feet wet. It combines some pretty basic oils along with lanolin and marshmallow root powder for that extra slip. It’s then scented with a dreamy vanilla and fig fragrance oil.
Homemade Bacon Soap Recipe: Made using real bacon (rendered) fat, this homemade bacon soap recipe yields nine hard, extra conditioning homemade soap bars perfect for the shower! So there are plenty to go around to all of your bacon loving friends. Scent this homemade bacon soap with a bacon fragrance oil or your sweetheart’s favorite scent – your choice!
Easy Unscented Goat Milk Soap Recipe: Not only is this goat milk soap perfect for those who allergic to fragrances, but it also makes a great facial soap. Plus it’s skin conditioning ingredients are perfect for those who suffer from dry or maturing skin. This homemade unscented goat milk soap recipe uses a simplified process for making goats milk soaps by calling for goat milk powder in lieu of fresh goat milk to help ensure success even for a first time soapmaker.
Budget Mango & Coconut Milk Soap Recipe: This straight forward, four oil cold process soap recipe is made using coconut milk powder, pureed ripe mango and a mango fragrance oil.
Other helpful links to get you started.
Now that you know how to make homemade cold process soaps and you have a few beginner cold process soap recipes to get you started, here are a few helpful links to lye calculators and other helpful websites, tools and charts you may need during your soapmaking journey. Also be sure to check out The Soapmaker’s Resource Directory for soapmaking suppliers listed and organized by product, country and vendor name. Other soapmaking books of interest include Smart Soapmaking by Anne L. Watson, Advanced Soapmaking by Mary L. Humphrey and Soap Crafting by Anne-Marie Faiola.
Tools & Charts & Soapy DIY’s:
How to Use a Lye Calculator to Make Your Own Soap Recipes
Weight Conversion and Percentage Calculator
Chart with Properties of Soapmaking Oils
Additional Chart with Properties of Soapmaking Oils
FDA Cosmetics Handbook
How to Re-size a Batch of Cold Process Soap
Mountain Rose Herbs, Organic & Sustainable Soapmaking Supplies
How to Line a Wooden Soap Mold
How to Make a Wood Loaf Soap Mold
How to Make a Loaf Soap Cutter
How to Create Custom Soap Labels
DIY Ideas for Soap Labels
Large Collection of Cold Process Soap Recipes
How to Add Milk to Lye for CP Milk Soaps
Understanding Glycerin Rivers in CP Soap
Understanding Gel Phase
Calculating the Amount of Soap to Fill a Soap Mold
Soapmaking Oils Chart with Properties & Notes on Breaking the “Rules”
How to Start Your Own Soap Business
For more of my homemade soap recipes as well as bath and beauty DIY’s be sure to visit Rebecca’s Soap Delicatessen. You can also follow me on Pinterest for collections of not only my homemade soap recipes and beauty DIY’s but also some of my favorites from around the web.
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