cold process soap making guide

Are you interested in making cold process soap? Great! You’re in the right place. This page will let you know what you need to get started and will also direct you to useful resources and posts.

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Why make your own cold process soap?

There are many reasons that people like to jump into the world of soap making. A few include:

  • The need to use more natural products. Many people with skin conditions, such as eczema, or other sensitivities do well when using gently formulated handmade soap.  Many soap makers begin their soapmaking journey to help relieve their skin condition or a family member’s skin condition. Check out this blog post of the benefits of using handcrafted soap.
  • The craft is addicting! I have a confession…I used to be a craft junkie! Soap making was something I tried to feed my crafting addiction. Once I made soap, I was hooked. I don’t make many other crafts these days…soap making is my drugahem – craft of choice!
  • You get to be an artist! Soap making is a wonderful mix of chemistry and art. Soap makers make stunning designs using soap, even replicating beautiful swirls similar to those found in handmade marbled paper.
  • There is a move towards simplifying life and making things with our own two hands again. People are starting to grow food again, raise chickens and many other DIY projects. Soap making fits this lifestyle perfectly. There is nothing more satisfying than creating something yourself.

What is soap?

  • Soap is an emulsifier and surfactant. You’ve probably heard of the term emulsifier. An emulsifier is a substance that creates an environment in which water and oil can mix.
  • Soap cleans your skin by emulsifying oil and water together. The emulsified mixture is then rinsed off, leaving behind squeaky-clean skin.
  • In soapmaking, a combination of base oils, such as coconut oil, olive oil and avocado oil, is mixed with a lye solution. The chemical reaction, which then takes place, is called saponification. After saponification, we are left with completely new substance, soap! Soap is made up of the salts of fatty acids, natural glycerin and, because we superfat our soap, a bit of unsaponified oils which give our soap emollient and conditioning properties. There is no lye left in the finished soap.
  • If you want to delve into the chemistry of soapmaking, I highly recommend reading Kevin Dunn’s book, Scientific Soapmaking.

Equipment & Tools

You don’t need a bunch of expensive specialty equipment when just starting out.  You might even have some of these items available in your home.  Some of the items can even be picked up at garage sales or thrift stores if you want to save a few bucks.

Keep your utensils and containers that are used for soapmaking separate from those that you use to cook with.  Most people believe this is because of the sodium hydroxide; it has actually more to do with fragrance and essential oils that you use.  You don’t want your mac and cheese tasting like patchouli and orange essential oil.

  • Digital Scale – Most ingredients for making soap, especially the oils and lye, need to be weighed using a scale.  I recommend getting a digital scale that plugs into the wall.  One run with batteries only can be unreliable once the batteries start running low.  You want a scale that has options for both grams and ounces.  Make sure it has a tare button to zero out the weight of the measuring containers.
  • Mixing Utensils – Stick to spoons and spatulas made out of silicone, hard plastic or stainless steel. Although mixing soap with a big wooden spoon is a romantic notion, avoid wood as it can splinter over time when exposed to lye. You don’t want splinters in your soap!
  • Stick Blender – You will need a stick blender or immersion blender to blend the soap. Although this isn’t necessary, it does help cut down on the mixing time to bring your soap to emulsion and trace. They come with plastic or stainless steel shafts – either will work. Be sure you get one with a detachable shaft to make cleanup easier.
  • Mold – Soap is fluid when poured. You will need something to hold it as it hardens overnight. There are many types of molds you can use for soaping ranging from more expensive wooden loaf and slab molds to inexpensive “found” molds including Pringles cans, yogurt cups and shoeboxes. My favorite molds to use are silicone molds, as they don’t require lining. For mold ideas, check out this blog post.
  • Containers for Weighing out Oils and Mixing Soap – I recommend using a stainless steel pot, a large glass measuring bowl, a bucket or heavy duty paint mixing containers. **Sodium hydroxide reacts with aluminum, creating hydrogen gas, so make sure that the only metal you use is stainless steel. Check out this detailed post on how to pick out containers for soap making.


The base of a handcrafted soap is made up of oils and lye.

  • Oils – Oils (and butters and fat) can be found locally but I recommend purchasing from soap suppliers to save some money. Refer to the Soapmaking Oil Chart for more information on the properties of oils and butters in soap.
  • Sodium Hydroxide – Sodium hydroxide (also called lye) is what turns your oils into soap! Where does sodium hydroxide come from?  Sodium hydroxide (along with chlorine stemmed from the same process) is the result of a salt solution (sodium chloride in water) processed by electrolysis.  Salt deposits are found all over the world, some of the most pure deposits are found underground.  The salt is mixed with water and pumped from the earth as salt brine.  It is then put through the process of electrolysis to make sodium hydroxide and chlorine.  Electrolysis is basically a method of passing an electric current through a liquid or solution.
  • Liquid – Water is typically used to dissolve the lye.  Distilled water is preferable as tap water can contain minerals, metals and other contaminants. You can also use alternative liquids such as milk, beer, wine, juices…etc. Using alternative liquids is an advanced technique. Start with water.

To this base of oils + lye + liquid, we can add scent, color and other additives.

Scenting Your Soap

Both fragrance oils (synthetic) and essential oils (natural) are used to scent soap.

Fragrance oils are synthetic aromatic oils that are produced in a lab.  They are usually made up completely from synthetic components or a mix of synthetic components and natural essential oils.  Fragrance oil producers and perfumers are unlimited as to what aromas they can mimic and you’ll find aromas that reflect those naturally found such as lavender, peppermint, orange and also more unique ones such as hot fudge sundae, leather, cherry and even puppy’s breath!

Usage in soap:  Fragrance oils can typically be added to soap at .5 – 1 ounce per pound of oils.  Refer to the supplier’s guideline and recommended usage rates.  If the supplier doesn’t have one, then I would start at .75 ounce per pound of oils and go up or down from there.  Most reputable suppliers will be able to recommend usage rates and also will be able to tell you how the fragrance oil reacts in the high pH environment of soap.

Essential oils are oils extracted from part or the whole of a plant by distillation or expression.  Some common essential oils available to soapmakers are peppermint, lavender, tea tree, orange, patchouli, basil, lemongrass, litsea, anise, plus many more.  Essential oils also have therapeutic qualities and just like perfumers, soapmakers mix them together to create synergistic blends especially good for aromatherapy.  Essential oils are considered a more natural way to fragrance soap.

The topic of essential oils is too great and important of a topic for me to discuss in this basic guide.  If you’d like to use them, I really encourage some further reading on the topic to learn their properties, uses and contraindications.  There are several wonderful essential oil books out there.  I highly recommend books by Robert Tisserand ( or Kayla Fioravanti (

Here are some helpful blog posts on scenting soap.

Coloring Your Soap

There are many types of soap colorants you can use to color your cold process soap.  Here are some of the more widely used types.

Natural Pigments (Oxides and Ultramarines) – Once mined from the earth, oxides and ultramarines are now lab-created to ensure purity. These lab created materials are considered “nature identical” which means that their chemical makeup is the same as how they occur in nature. Pigments are usually stable in high pH mixtures and tend to stay true to their color in cold process soap. Start with a quarter of a teaspoon per pound of oil and go up from there to get the desired color you are looking for. Mixing can sometimes be tricky; I recommend mixing the dry pigment with a teaspoon or more of oil or liquid glycerin and using your stick blender to disperse the colorant in your soap.

Mica – Mica is what gives cosmetics, paint and other products sparkle. Mica comes in tiny flakes – the bigger the flakes the more surface area for light to reflect, the mores sparkly it will be. Mica is colored using pigment or dye coatings. Micas can be hit or miss in the high pH of soap so make sure the micas that you buy are cold process soap stable.  Micas colored using dyes can bleed or migrate in your soap. I use 1/2-1 teaspoon per pound of oil. You can go up or down from there depending on the shade of color that you want. I mix mica into my soap using a mini-mixer (coffee frother).

Cosmetic Pigments – Cosmetic pigments are super-popular these days for those wanting crazy bright colors in soap. Cosmetic pigments (also called neons and brights) are plastic coated dyes. Because of the coating, they don’t bleed or morph in soap.

Natural Colorants – My favorite colorants to use are natural colorants including spices, herbs, clays and other botanical powders resulting in beautiful natural colors of cold process soap.  Natural colorants are generally added by oil infusion, lye infusion or by adding powder at trace.  Common natural colorant powders include turmeric, paprika, cinnamon, alkanet root, madder, powdered mint, rose clay and charcoal. There are so many to choose from! Usage rates vary, but typically you can start with 1 teaspoon of natural colorant per pound of oil and go up or down from there.

Dyes – Dyes are synthetically produced colorants that are commonly found in the food and cosmetic industry.  Dyes are probably the most finicky to work with, especially in the high pH of cold process soap. Even “tested and true” dyes advertised by suppliers have been hit or miss in my experience with them. You want to stick with dyes that are FD&C (Food, Drug and Cosmetic) or D&C approved for skin care products or labeled as cosmetic grade. Most food colorant dyes will not work in cold process soap because of the high pH.

Here are some helpful links and resources for coloring soap!

Additives in Soap

You can add all sorts of additives to your soap such as oatmeal, clay, orange peel powder, charcoal..etc. Visit our soapmaking additive chart to figure out how much to add to your soap.

Lye Safety

Sodium hydroxide is a highly caustic chemical.  Contact with skin and eyes can cause severe irritation, burns and blindness.

  • When handling lye, you must wear safety goggles to protect your eyes and gloves to protect your hands.  One splash of lye solution into your eye can permanently damage your eyesight.
  • Always make sure your environment is free from distractions including pets, children and other family members.
  • When making your lye solution, always add your lye to the water- NEVER add your water to the lye or a volcanic eruption can occur. One way to remember this is to say to yourself, snow falls on the lake, lye falls on the water’. Make sure you mix your lye in a well-ventilated area as it does let off fumes when first mixed with water.
  • An Important Note on Vinegar – If you’ve done some research on soapmaking you have heard or come across that vinegar is often used to neutralize lye.  Though this is true, you never want to use vinegar on your body to neutralize lye solution you might have splashed on yourself.  This is because vinegar neutralizes lye by “flashing it out” and can cause an even greater burn by doing so on your skin.  If lye has gotten onto your skin, simply rinse off with cold water.  If lye has gotten into your eye, rinse with water and contact poison control or go ahead a get to the emergency room.  Lye can permanently damage your eye causing blindness.  No matter how comfortable you become with soaping, always wear proper eye protection.  It only takes one splash to damage your eyesight forever.
  • If you spill lye on the counter or floor you can spray with a vinegar solution to neutralize and wipe up with a paper towel.
  • Bottom line:  If you get lye on your skin, flush with water.  If you get lye on a surface, neutralize with vinegar and rinse/wipe up with water.

Curing and Storing Your Soap

  • Cold process soap needs to cure 4-6 weeks.  During the cure time, water evaporates making your soap harder and longer lasting in the shower.  Also during this time, the last bit of saponification takes place making your soap less harsh and much nicer to use.
  • Soap is best cured in a cool dry area with plenty of air circulation.  Line up the soap in rows making sure that the bars are not touching.  If your curing rack is metal, make sure it is stainless steel and not aluminum as there can be a tiny amount of active lye upon cutting.
  • To better understand saponfication and curing, read this blog post.

Ready to Make Soap?

Advanced Topics in Soap Making and Helpful Links

These are just a bunch of random topics that I’ve blogged about or created resources on. I recommend reading through them before you begin your soap making journey so you’ll have a broader view on the process and what goes on. 🙂 So grab a cup of tea and enjoy!

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