What is Homemade Soap?

What is Homemade Soap?

True Soap, by definition, is fats or oils mixed with an alkali. The oil comes from an animal or plant. Such as Lard (From swine/pigs) and Olive oil (from olives). There are many to choose from! While the alkali is a chemical called lye. In bar soap-making, the lye is sodium hydroxide. Liquid soap requires potassium hydroxide.

Combining and then heating oil and lye results in soap. This chemical reaction is called saponification. Without lye, saponification isn’t possible, so lye is necessary to create real soap.


There are two methods for making homemade bar soap:

  • Hot process. In hot process soap-making, external heat accelerates saponification. Most soaps can be used the next day, though it’s ideal to wait 1 week if you want a harder bar.
  • Cold process. Cold process uses the internal heat that’s naturally produced during saponification. The bars will completely harden in 4 to 6 weeks.


The Pros and Cons of each process

Hot Process:


  • You can customize every single ingredient, including oils. You have many options to choose from.
  • The additional heat speeds up the saponification process. Hot process soap can be cut within one day and used right away.
  • The bars have a rustic appearance and a less smooth texture than cold process. Whether you like this look is personal preference.
  • Hot process can be made in a Crock-Pot or double boiler.
  • The thick texture makes it great for suspending heavier additives.
  • It's generally considered to be a more “natural” bar of soap.
  • Cleanup is easier because the leftovers in the slow cooker/Crock-Pot are already soap.


  • The thick texture of hot process soap makes some techniques difficult, like layering and swirls.
  • If your fragrance or essential oil has a low flashpoint, some makers find the higher temperatures can burn off the fragrance, causing it to fade.
  • As the soap cooks, it expands. Because of the possibility of overflow, it’s important to not leave it unattended.
  • It's difficult (but not impossible) to add fresh ingredients like milk and purees; they tend to scorch during the cooking process.


Cold Process:


  • This method allows you to customize every single ingredient to suit your personal preferences.
  • You can add fresh ingredients like milk and fruit/vegetable purees because you control the saponification process.
  • The trace of cold process soap can be manipulated for a variety of techniques and designs. Thin trace can be used to make swirls, while thick trace creates soap frosting.
  • With so many technique options, it’s a great way to get creative. The sky's the limit!
  • The thick texture makes it great for suspending heavier additives.
  • It's generally considered a more "natural” bar of soap.


  • It's made with sodium hydroxide lye, which can be dangerous if it's handled incorrectly. 
  • Cold process soap takes about 4-6 weeks to cure. The bars can be used before then, but they will be softer and won't last as long in the shower.
  • Some colorants can morph in the high pH environment of cold process soap.
  • Fragrance oils can react with the high pH of cold process soap in negative ways, causing acceleration, ricing, or seizing. Always make sure your fragrance behaves well in cold process!
  • Vanilla Color Stabilizer is not reliable. Fragrance oils with a high vanilla content will turn the soap brown.
  • Because cold process soap is opaque, glitter doesn't show up very well. It still looks great sprinkled on top though.
  • Cleanup can be a long process depending on how intricate your design is.



Since you will be working with lye, which is a chemical. You will need the proper safety equipment while working with lye.

Soap-making safety equipment:

You’ll need safety equipment, such as:

  • safety goggles or face shield
  • rubber or latex gloves
  • long-sleeved shirt
  • pants
  • apron
  • well-ventilated work area
  • closed shoes

Qualities of Soap

When creating soap recipes, ingredients can be adjusted in order to control the qualities of the soap produced. There are six qualities of soap.


  1. Hardness: The hardness value describes how hard the soap is. Different fats can create soaps with different hardness values. The higher the hardness value, the harder the soap will be.
  2. Cleansing: The cleansing value describes how the soap grabs onto oils therefore, how well it cleans. If a soap that has too high of a cleansing value may the protective oils in your skin. This will have a drying effect on your skin.
  3. Condition: The condition value describes the soap’s emollient content or well known as the moisturizing properties. This means the soap stay on the skin to help the skin retain moisture and makes skin feel soft and soothe the skin.
  4. Bubbly: The bubbly value describes how much lather or bubbles the soap will create. Higher values produce foamy, fluffy lather while lower numbers will produce a creamy lather with fewer bubbles.
  5. Creamy: The creamy value is almost the reverse of the bubbly value. As the creamy value increases, the creamier the lather of the soap will be. The lower the value, the more foamy lather the soap will create. Soap made with olive oil creates creamy soaps that has no bubbles.
  6. Iodine: The iodine value is another indicator of the hardness of a bar of soap. The lower the iodine value, the harder the soap will be.


Quality Value Range

 Hardness 29-54
Cleansing 12-22
Condition 12-22
Bubbly 14-46
Creamy 16-48

>70 for Soft Soap

<70 for Hard Soap



Soap Making Terminology


Below is a list of some common terms used when soaping. This is by no means a complete soaping dictionary, there are many more terms. But these are ones you will hear or see often.


Absolute-  Derived from plants through a method of extraction involving solvent, this term refers to the highly aromatic, concentrated oil that is extracted.

Additives-  Ingredients that can be added to processed soap, which are not included in the original recipe which was used to calculate the SAP value for lye purposes. This would include ingredients such as fragrance oil, soap colorant, optiphen, vitamin E, herbs, clay, etc. (Note: If you have a super fat recipe, any leftover or excess oils, butters, or fats, not saponified by the lye solution would also be considered an additive.)

Alkali-  Any compound with a pH higher than 7. Alkali is also referred to as a base. Both sodium hydroxide and potassium hydroxide are alkalis.

Allergen-  An element that can cause an allergic reaction ( such as irritation, redness, swelling, discomfort) in one person, but does not adversely affect another.

Anhydrous-  Not containing any water.

Anti-bacteria-  The ability to fight off bacteria successfully.

Anti-oxidant-  Natural or synthetic elements that have the ability to decrease oxidation, preventing breakdown or spoilage.

Anti-septic-  The ability to fight or decrease an infection topically (on the skin), by restricting the growth of microorganisms.

Aromatherapy-  The use of certain fragrance or essential oils that can reform a person's mood or actions.

Aromatic-  Being odoriferous, having a strong odor; usually found as a pleasant scent.

Astringent-  An element with the capability to pull together or constrict skin tissues (or pores), concurrently restricting the flow of natural secretion from the skin.

Botanical-  Directly from or related to plant or plant life.

Carrier Oil-  A substance that is used to dilute a fragrance or essential oil so that it is safe for use on the body. Carrier oils can also refer to an oil that is used to carry the fragrance out in a product like roll on perfume.

Castile Soap-  Originally denoting an olive oil soap bar; which was named for the region in Spain where it originated. This term now is commonly given to any soap containing 100% olive oil (meaning no other soaping oil is used in the recipe).

Caustic-   A very strong acid or base, this refers to a substance that by means of a chemical reaction will breakdown or destroy other elements under certain conditions. Caustic material is very dangerous especially to elements containing water such as organic tissue. An example of a caustic ingredient is sodium hydroxide (lye).

Cold Process Soap Making-  The term cold process is actually attributed to the fact that there is no outside heating source required for saponification; the lye mixture itself heats and saponifies the oils. This process, abbreviated as CP, involves diluting lye into distilled water to form a lye solution. Takes longer for saponification to process, curing time is 4 to 6 weeks.

Cold Process Oven Process Soap Making-  This soaping process; usually referred to as CPOP, involves diluting lye into distilled water to form a lye solution. The molds are then placed into a 170 degree oven for 1- 2 1/2 hr. Within 24 hours, the soap is solid enough to be removed from the mold and cut, exposing more soap area to oxidation. To ensure milder and harder bars of soap, the soap is then cured for 2-4 weeks.

(Note: Using a CP bar of soap that still has active lye will irritate and burn the skin. A pH strip test is the best way to test if your soaps are safe to use.)

Cosmetic Grade-  Available in different grades which are priced accordingly, this refers to ingredients that are safe for use on the body or in cosmetics.

Cure-  The time period that it takes to saponify soap so that there is no longer any active lye present.

D&C-  D & C is the abbreviation for drug and cosmetics. If something is approved as D&C safe, then it can be used for cosmetics or in drugs.

Deodorize-  The removal of a scent from something. Within soaping reference, many soaping oils are deodorized to take away their natural scent. Using deodorized soaping oils is one way to keep your fragrance true to their original aroma.

Detergent-  This agent has cleansing benefits and performs very similar to soap. However, detergent is made from chemical compounds other than the fats/oil/butters and lye (like soap). When a detergent is found in the ingredients list of a product, it must be labeled as a cosmetic product under the specific guidelines of the FDA.

Dreaded Orange Spots-  These spots occur in processed soaps that contain are large amount of soaping oils that have turned rancid. These spots are orangish, brownish, beigeish in color. It is believed that they are caused by using soaping oils which are old.

Embeds-  Embeds refer to pieces of soap that are placed into the processing soap during the light trace stage.

Emollient-  Refers to having certain properties that are both soothing and softening to the skin.

Emulsifying Wax-  This is an emulsifier (a product that allows water based ingredients and oil based ingredients to bind together) used in hair and skin care. Emulsifying wax is used in skincare recipes to allow for thick creams.

Emulsion-  This is when two liquids which normally would not blend together, are blended together (oil/water). Typically, the process involves an emulsifier (a product that allows water based ingredients and oil based ingredients to bind together).

Essential Oil-  Natural volatile oils that are extracted through various means from plant matter. Extraction could take place by means of: Distillation, expression, or the use of chemical solvents.

Exfoliate-  An additive that is added to processed soap that allows for the removal of dirt and debris from the skin, as well as, the removal of dead skin cells themselves, for healthier skin.

Exothermic-  A term referring to the heat that is produced and released when a chemical reaction occurs. Examples of an exothermic reaction would be when lye is added to water or when the lye solution is added to the oils and butters.

Extract-  For essential oils, this is when the oil can be extracted from the plant without the use of any chemical solvents. This is the most pure, concentrated form of an essential oil.

F,D&C-  F,D&C is the short abbreviation for Food, Drug, and Cosmetics. If something is F,D&C approved, that means that it is a safe ingredient for use in food, drug, and cosmetics.

Fatty Acids-  Fatty acids are compounds either saturated or unsaturated, that are found in all fats and butters. The fatty acids are what is responsible for giving your soap bars conditioning, creamy lather, bubbles, hardness, and cleansing ability.

Fixed Oils-  These are oils such as olive, palm, and coconut, that can be heated without evaporating.

Flash Point-  The possible lowest temperature that will inflame the vapors of a liquid when introduced to a source of ignition. Flashpoints are available for every fragrance and essential oil that Natures Garden carries. They are located in three places, on the website under the fragrance information, on the specific MSDS sheets, as well as on the fragrance labels themselves. Fixed oils also have a flashpoint.

Fragrance Oil-  The blended combination of essential oils, synthetic aroma chemicals, and resins to produce a liquid that is extremely aromatic.

Gel Phase-  A possible phase of saponification, since not all soap batches will do this; occurring in the beginning of the process, this refers to the short period of time when the soap batter transforms to a warm clear gel. This gel will then slowly return to being opaque, but it will also be a little bit more solid and cooler.

Glycerin-  A natural emollient and humectant, glycerin is a product of processed soap. It is also often removed from commercial brands soaps and used to created creams and lotions.

Hot Process Soap Making-  This soaping process, generally referred to as HP, has steps very similar to the CP soap steps, but varies in that you are adding heat to the equation to speed up the saponification process. The heat sources are usually a crock pot or stove top. Although a cure time for these soaps is not required, to get a milder and harder bar of soap, a cure time of 1 week is advised. The final soap bars will have a very rustic appeal.

Humectant-  An ingredient that not only attracts water from the environment, but also aids the skin in absorbing the water as well.

Hydrating-  Something that provides moisture or water to the skin.

Hydrogenated Oil-  An oil that has the addition of hydrogen added to it to make it a solid or semi solid at room temperature. The process of hydrogenation helps to decrease the chance of oils turning rancid.

INCI Name-  Mandatory for labeling in the US and Canada, the INCI names were created to ensure that all ingredients would be listed the same on various cosmetic products. This also allows for ease on consumers when comparing ingredient lists on cosmetics. INCI stands for International Nomenclature Cosmetic Ingredient.

Infusion-  Taking an additive such as a herb, and allowing it to steep in a liquid to extract the herb's beneficial aspects.

Insoluble-  This means not able to be dissolved. Oils/Butters/Fats will not dissolve in water.

Irritant-  Much like an allergen, irritants cause disturbing and painful reactions to skin.

Lye-  Essential to the saponification process, lye is a caustic base. Lye can also be referred to as either sodium hydroxide (used to make bar soaps) or potassium hydroxide (used to make liquid soaps).

Lye Discount-  The method of purposely decreasing the amount of lye that should be included in a soaping recipe.

Melt and Pour Soap Making-  This soaping process, usually referred to as M&P, involves using soap that has already gone through the saponification process. The per-fabricated soap base only needs a few steps before use. The soap is finished and can be used once it has hardened.

Melting Point-  The temperature at which a soaping oil will turn from a solid to a liquid, or starts melting.

MSDS-  The abbreviation of Material Safety Data Sheet. These sheets contain all of the relevant information of a specific material.

Natural-  Anything that is of the earth, not containing any man made or synthetic additions to its makeup.

Nutrient-  Within the realm of soap making, this refers to anything that is beneficial or has favorable advantages for the skin.

Organic-  Without the additions of anything man made or chemically altered, this term denotes anything that was once living.

pH scale-  A form of measurement for the acidity or alkalinity of a substance in ratio to water. Ranging from 0-14, the lower the number, the more acid it is. The higher the number, the more alkaline. A pH of 7 will denote neutral (water has the pH of 7). Processed soap will have a pH of 8.5-10.5 when cured completely.

pH strip-  Litmus paper containing water soluble dyes that when dipped into a liquid or set on a bar of soap will show a color. The color is then compared to a chart to find the pH level.

Photosensitive-  A substance that once used on the skin will make the skin super sensitive to the sun or to sunlight; increasing the chance of a sunburn in some people.

Preservative-  An ingredient that is added to a substance that will prevent the breakdown and spoilage from microbial growth.

Potassium Hydroxide-  Symbolized as KOH, this is used for lye solution of gel or liquid soaps. Also known as caustic potash. This ingredient is a very strong base with a pH of 14. Note: The SAP values of your recipes fats/butters/oils will vary depending on whether you are using sodium hydroxide (NaOH) or potassium hydroxide (KOH).

Rancidity-  The breakdown or spoilage of oils/butters/fats used in soaping. Often, there is a stale or off smell due to the decomposition of the oil/butter/fat.

Rebatch-  Considered a do-over in the soap making process, this process involves the use of soap that was already crafted through CP or HP. The processed bars are grated down and melted with a heat source, usually a crock pot, but other sources are used as well.

Refined oils-  These are oils that have been filtered, removing any impurities in the oils.

Safety Equipment-  A category for all of the equipment used to keep one safe during the soaping process. This equipment includes but is not limited to: Safety goggles and/or face shield, rubber gloves, a face mask, aprons, etc. This category would also include items like protective coverings for work areas, fire extinguishers, bottles of neutralizing substances (such as vinegar for lye spills), first aid kit, etc.

Saponification-  This is the process of the chemical reaction that the lye solution and oils/fats/butters go through when making soap. Saponification produces both soap and glycerin. Glycerin naturally occurs as a byproduct of this chemical reaction.

SAP Value-  The abbreviation for Saponification Value. This refers to the number of milligrams of lye that is needed to completely saponify one gram of a specific oil/fat/butter in a soap recipe. Note: The SAP values of your recipes fats/butters/oils will vary depending on whether you are using sodium hydroxide (NaOH) or potassium hydroxide (KOH).

Seize-  A term referencing the condition of the soap batter when saponification has occurred enough that the batter is no longer a liquid, and has started to solidify. This occurs while mixing together the ingredients of a soap recipe when the batter becomes too thick to mix easily or pour into a mold.

Soap Measurements-  Soap Measurements are measured in weight, not volume.

Soda Ash-  Sometimes forming on processed soaps, this powdery substance has no direct negative effect on soap bars. Soda ash can be cut or wiped off bars. Insulating soaps while in the mold will help prevent soda ash. Soap that has soda ash can be sprayed with rubbing alcohol to improve the appearance of your soap.

Sodium Hydroxide-  Symbolized as NaOH, this is used for lye solution of solid bar of soap. Also known as caustic soda. This ingredient is a very strong base with a pH of 14. This is the component that is interchanged with KOH (Potassium hydroxide) for saponifying gel or liquid soap recipes. Note: The SAP values of your recipes fats/butters/oils will vary depending on whether you are using sodium hydroxide (NaOH) or potassium hydroxide (KOH).

Soluble-  A substance that can be dissolved in a liquid.

Superfat-  This term involves purposely adding an excess of soaping oils or fats to your batter that are not included in your calculated recipe for lye saponification. This is done to intentionally make your soap bars richer in soaping categories such as creaminess, moisturizing, bubbles, etc.

Surfactant-  A substance that reduces the surface tension of a liquid when it is dissolved. In soap, surfactants allow for the dirt and impurities to be rinsed off of the skin.

Synthetic-  Something that is created chemically. Not natural.

Tallow-  Rendered from animals, this is the hard fatty substance used for soap making.

Trace-  This term references the stage in the soaping process where the batter begins to thicken because of the saponification process. You will know if your soap batter is at trace by drawing up some of the batter with your spoon to see if it leaves any trails on top. If the lines in the batter disappear, the batter is not in full trace. If the lines stay visible on the surface, then your batter has traced.

Vegan-  Products that are produced without the use of any animal ingredients or animal parts. If a product contains tallow/lard/beeswax, it cannot be vegan.

Volcano Effect-  This term describes when water is added to lye, WHICH SHOULD NEVER BE DONE! The top layer of the lye starts to dissolve from the chemical reaction with the water. Immediately, the water starts dissolving and releasing heat. The heat causes a hard crust to form, and the water starts evaporating. The lye that is below the crust remains dry, and untouched by the water. As more water is added, pressure starts to build from the dissolving and heat release. The crust ruptures from this pressure and force, causing the dry lye, partially dissolved lye, steam, and boiling water to spew out the top resembling and active volcano eruption. ALWAYS ADD LYE TO WATER!

Volatile-  Oils that will evaporate quickly under normal temperatures.

Water Discount-  The method of purposely decreasing the amount of water that should be included in a soaping recipe. Doing so will accelerate trace and the saponification process. Not recommended for newbie soapers.