Glossary of Terms » Par Par Academy of Soaps & Cosmetics

For Soaps & Cosmetics

As a novice soap maker, many of the words you encounter are overwhelming. All of these unfamiliar words is like learning a new language in addition to learning to make soap. For the advanced soap maker, we have included advanced technical and chemistry related terminology.

The following is a complete glossary of soap and cosmetic making terms and definitions to assist you in your soap journey. Where applicable, access in-depth articles by clicking on the term’s header.


A
Absolute (perfumery) Both used in perfumery and aromatherapy, absolutes are similar to essential oils. They are concentrated, highly aromatic, oily mixtures extracted from plants. Whereas essential oils typically are produced through steam distillation, absolutes require the use of solvent extraction techniques or more traditionally, through enfleurage. Absolutes employed in perfumes and cosmetics and to a smaller extent, soap-making can add unique and delicate features.
Acid Value: (fatty acids) The Acid Value is the numerical amount of milligrams of potassium hydroxide (KOH) required to neutralized by 1 gram of a free fatty acid.
Acid:(Acidic) A solution which has a pH less than 7. See also pH.
Additives Any ingredient added to soap that does not saponify and become part of the soap-salt molecule itself. Therefore, lye, water, and saponified oils/fats/butter are not considered additives. Examples of additives are color additives, essential oils, botanical, alcohol, minerals, and pigments.
Alkali:(Alkaline) A solution which has a pH greater than 7. Alkali is a synonym for a base. See also pH.
Allergen A reactive substance that causes an allergic reaction in one individual but has no adverse effect on another.
Allergic Reaction Hypersensitive response to a specific substance, called an allergen, which can be contacted through the skin, inhaled into the lungs, swallowed, or injected. The body's reaction to an allergen can be mild, such as a localized rash, or life threatening, such as anaphylactic shock.
Ammonium Carbonate Ammonium carbonate is a salt with the chemical formula (NH₄)₂CO₃. Since it readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a leavening agent and also as smelling salt.
Anhydrous an·hy·drous free from water and especially water that is chemically combined in a crystalline substance
Antibacterial A substance that can fight bacteria effectively. Antibacterials are used in soaps and disinfectants, while antibiotics are used as medicine.
Antiseptic Antimicrobial substances applied to living tissue/skin to reduce the possibility of infection, sepsis, or putrefaction.
Aromatherapy The practice of using bark, stems, flower, leaves and roots to extract natural oils for enhancing the psychological and physical well-being.
Astringent An astringent is a water-based solution that, when applied to the skin, is meant to shrink or constrict the skin. It is a stronger form of a toner and is formulated with SD Alcohol or Denatured Alcohol that gives the skin a tight feeling. (The tight feeling is a sign of dehydration and not a sign of clean skin, as many think.) Two common cosmetic examples are calamine lotion and witch hazel.
Attar A perfume or essential oil obtained from flowers or petals. Also known as otto and is usually very expensive.

B
Base: The alkali used in soap making. Sodium Hydroxide, Ammonium Hydroxide and Potassium Hydroxide are bases.
Base Note See Notes
Batch Code A numbered record of each batch of soap. The Batch Code Sheet lists the company of manufacture, the name of the soap maker(s), the date made, the ingredients, the ingredients' sources and amounts, the ingredients' lot numbers, any variation from the normal soap making procedure, the cure date or "do not use before" date, the expiration date, and any additional comments.
Beeswax The wax secreted by bees to make honeycombs. It is considered a natural product. It varies in color from white to yellow, is a waxy solid at room temperature, and has a melting point of 144 to 147°F (62 to 64°C). Used as an additive in soap to make a harder bar. In Melt and Pour soap it may cause cloudiness in the soap and affect lather, depending upon the amount and soap base being used.
Best If Used by Date (Good Manufacturing Practices) The date by which a product or ingredient should be used before it is considered unusable due to quality issues. In Melt and Pour soap bases, one condition that may happen after this date is that the MP soap base loses enough water to become dehydrated and will not work well.
Bloom (MP) The white crystal like substance that forms on the top of MP soap due to water loss (dehydration) of the soap. In MP soap, it is commonly caused by soap melted in the microwave or left out unwrapped.
Botanical Of or relating to plants or plant life.

C
Carrier Oil Any liquid plant based oil used to dilute essential oils for use on skin surfaces.
Castile Soap A 100% olive oil soap named for a region is Spain from where it originated.
Caustic: A corrosive substance that burns or destroys organic tissue by chemical action. Caustic can refer to an acid or a base but is typically used to describe the action of an alkaline base. Lye is a caustic substance.
Caustic Potash Potassium Hydroxide is another name for Caustic Potash. It is the alkali (base) used in liquid soap making.
Caustic Soda Sodium Hydroxide (lye) is another name for Caustic Soda. It is the alkali (base) used in bar soap making.
Cold Process Method: (Abbreviated: CP) Soap making method where the starting ingredients of lye solution and a blend of oils/fats/butters are separately brought to their desired temperatures, mixed together, and allowed to react without additional heat.
Color Additives Any ingredient which when added to a product causes the product to change color. The European Union, Canada, and United States regulate the type of color additives which may be used in cosmetics, and also regulate the specific area(s) of the body to which a color additive may be applied. If an ingredient is added to a cosmetic for a specific functional or application purpose, and it happens to color the cosmetic, it is still considered color additive unless the color imparted is "clearly unimportant insofar as the appearance, value, marketability or consumer acceptability is concerned." [Quoted from US federal regulation 21CFR70.3(g)]
Color Fastness The ability of a color additive to not bleed, not fade in light, and not transfer its color to lather or articles.
Color Fastness The ability of a color additive to not bleed, not fade in light, and not transfer its color to lather or articles.
Complaint File A complaint file contains a record of a customer complaint, the date of the complaint, and the action taken by the soap maker.
Contaminate To make impure or unclean by contact or mixture.
Continuous Process A modern method of commercial soap making in which saponification takes place under pressure. Allows for the addition of base ingredients throughout the soap making process.
Cosmetic UNITED STATES: A cosmetic is defined as: (a) Articles intended to be rubbed, poured, sprinkled, or sprayed on, introduced into, or otherwise applied to the human body or any part thereof for cleansing, beautifying, promoting attractiveness, or altering the appearance, and (b) Articles intended for use as a component of any such articles; except that such term shall not include soap. [Food, Drug, and Cosmetic (FD&C) Act, Sec. 201(j)] CANADA: Cosmetics include any substance or mixture of substances manufactured, sold, or represented for use in cleansing, improving or altering the skin, hair or teeth and includes deodorants and perfumes. In Canada, soap is considered a cosmetic. [Canadian Cosmetic, Toiletry and Fragrance Association; Advertising Standards Canada; Health Canada June 1998 Revised June 2003] EUROPEAN UNION (EU): A cosmetic product is any substance or preparation intended to be placed in contact with the various external parts of the human body or with the teeth and the mucous membranes of the oral cavity, with a view exclusively or mainly to cleaning them, perfuming them, changing their appearance, and/or correcting body odours, and/or protecting them or keeping them in good condition. In the EU, soap is considered a cosmetic. [Directive 76/768/EEC]
Cosmetic Grade Ingredients that are approved for use in cosmetics like soap, bath and body products and make-up. These ingredients are often available in higher, more expensive grades.
Cosmetic Ingredient Dictionary A book published, usually annually, by the Personal Care Products Council. It contains the assigned INCI name for cosmetic ingredients and materials, as well as monographs for ingredients, lists of manufactures and a cross-reference from trade names to INCI names.
CP Acronym for 'cold process' soap making.
Copra The dried flesh or meat from a coconut from which coconut oil is derived.
CPHP Acronym for 'crock pot hot process'. Soap is brought to trace and then cooked until neutral in a crock pot.
CPOP Acronym for 'cold process/oven process'. Soap is made in the same manner as cold process but is then placed in the oven once moulded in order to force the gel stage.


D
D&C Abbreviation for 'Drug and Cosmetic'. Designates approved for use in drug and cosmetic products.
Decoction An extract obtained by the process of boiling botanical matter in a watery fluid to extract its virtues. As opposed to an infusion where the matter is steeped in water and not boiled.
Dehydration Excessive loss of water. In Melt and Pour soap base, dehydration may compromise the usability of the product.
Deliquescent The propensity of a material to dissolve or melt when in open contact with air. Lye has deliquescent properties.
Deodorize To remove scent from a product. Many oils used to make soap have an odour and some of them are deodorized before sale. This is beneficial when making scented soaps so that the fragrance remains true.
Dehydration Excessive loss of water. In Melt and Pour soap base, dehydration may compromise the useability of the product.
Detergent A synthetic, organic, liquid or water-soluble cleansing substance that acts similarly to soap but is made from chemical compounds rather than fats and lye.
Discount - Lye The word discount in this context means 'to reduce or use less'. With a lye discounted recipe, you are using less lye than is actually needed to saponify the entire amount of oils used in your recipe. This ensures that the final soap product does not contain any free lye and has extra oils to moisturise the skin. The usual amount of lye that is discounted tends to be around 5% - 10% but some recipes can go as high as 20%. ex. - on Soapcalc where is says "Super Fat/Discount %" (top right corner) you will see the default amount of 5%. If your recipe needs 100 grams of lye to fully saponify all of the oils, Soapcalc will calculate the recipe to have 95 grams of lye and this will leave some free oils in your final soap.
Discount - Water: The word discount in this context means 'to reduce or use less'. A water discount refers to using less water than the standard amount that is considered a 'safe' amount. This 'safe' amount of water tends to be about 36% - 38% percent of the amount of oils used in a recipe. If your recipe calls for 100 grams of oils, you would need about 36 grams of water. This range of water is considered easiest to work with, giving you plenty of time to mix in essential/fragrance oils and other ingredients before the soap becomes too thick to work with. The reason for discounting water is to produce a harder bar of soap faster. As soap cures, the water evaporates. If you have less water, the soap will be harder at the end of 4 weeks. Be aware that using less water can speed up the chemical process and if you're not careful, you could end up with your soap seized in the pot. I typically use between 33% and 36% water in my recipes and don't recommend going below 30%. Also note that discounting water does not make the soap cure faster....just makes the soap harder faster.
DOS An abbreviation for Dreaded Orange Spot. Can occur in soaps with a high percentage of oils that are prone to going rancid. Looks like small orange-beige spots.

E
Embed Soap A soap that has embed material suspended in it. This type of soap is frequently used with clear Melt and Pour soap base to showcase a design or object, or to make colored designs in opaque soap.
Emollient A substance used to soften and smooth skin. Vegetable oils and glycerine are emollients that help to retain skins moisture.
Emulsifying Wax A special wax that is used to combine incompatible substances like oil and water into a blended product like lotion.
Emulsion A blend of substances that are normally not mixable. Emulsifying wax when combined with oil and water create an emulsion.
Essential Oil A volatile oil that has been obtained from a plant for its scent, flavour or therapeutic properties.
Exfoliant An ingredient added to soap that is intended to remove dead skin cells and dirt from the skin surface.
Extract A substance, extracted from a plant by way of distillation, pressure or solvents, containing its essence in concentrated form.
Exothermic Characterized by the release of heat, often due to a chemical reaction. Soap is made as the product of an exothermic reaction between lye and fat.
F
F,D&C Abbreviation for 'Food, Drug and Cosmetics'. Designates approved for use in food, drug and cosmetic products.
FD&C and D&C Dyes Dyes which have been approved by the FDA for use in food, drugs, and cosmetics (FD&C) or use in drugs and cosmetics (D&C). Dyes are typically soluble in water and produce a very vibrant color. They are generally not UV-stable (colorfast) and will fade over time without the use of a color stabilizer. In MP clear soap base, these dyes stay clear. However the colors will migrate in a multicolored MP soap as both the dye and soap are water soluble. In hot or cold process soaps, some dyes react with the alkalinity of the soap which can alter the final color. Many blue dyes will turn to pink in cold or hot process soap.
Fatty Acids Compounds of carbon, oxygen and hydrogen found in fats and oils. They can be saturated or unsaturated. Of interest in soap making are Lauric acid, Myristic acid, Palmitic acid, Stearic acid, Oleic acid, Linoleic acid, Ricinoleic acid and Linolenic acid. These fatty acids are what give soap their bubbly lathers, hardness, stable lathers, cleansing and conditioning characteristics. A fatty acid molecule that has a saturated or unsaturated carbon chain, typically of 4 to 28 carbons, with a carboxylic acid group at one end. When a triglyceride is reacted with lye (sodium hydroxide), the fatty acids are released from the glycerin backbone, combine with the sodium hydroxide and form the sodium salt of the fatty acid. Examples: Lauric Acid: A fatty acid with a saturated carbon chain of 12 carbons. Found in coconut oil. Stearic Acid: A fatty acid with a saturated carbon chain of 18 carbons. Found in palm oil and lard. Oleic Acid: A fatty acid with an unsaturated carbon chain of 18 carbons and 1 double bond. Found in palm oil Linoleic Acid: A fatty acid with an unsaturated carbon chain of 18 carbons and 2 double bonds. Ricinoleic Acid: A fatty acid with an unsaturated carbon chain of 18 carbons and 1 double bond, and a hydroxyl group on the twelfth carbon of the chain. Found in castor oil.
Fixatives Substances used to anchor a fragrance or essential oil to slow the process of evaporation. Example: The essential oil ylang ylang will help to fix the other oils and make them last a little longer
Flash Point The lowest temperature at which the vapour of a combustible liquid can be made to ignite.
Fragrance Burn-off: When the intensity of the fragrance is reduced because the fragrance evaporates due high temperatures. This can happen when the fragrance is added to MP soap that is too hot or to cold/hot process soap that reaches high tempertures during the saponification process.
Fragrance Oil (FO): Synthetic imitations of essential oils and other scents.

G
Gel Stage: Once soap has been mixed to trace and has been poured into the mould it will begin to heat up. If the soap is properly wrapped and allowed to heat up enough, it will undergo a change. It will become translucent and take on the look of Vaseline. Most soap makers want their soaps to gel but some prefer soap that hasn't. Either way is fine.
Glycerine: A thick, sticky, clear substance created during the process of saponification. Handmade cold process and hot process soaps retain the glycerine whereas commercial soaps often remove it. Glycerine is a natural emollient and humectant. Also known as glycerol and glycerine. The glycerine molecule is three carbons long, with a hydroxyl group attached to each carbon. It is extracted through the saponification of triglycerides, which releases the glycerin molecule. It is a clear,viscous liquid at room temperature which tastes sweet. Glycerin is used as an additive to make transparent soap and is typically present in MP soap base to improve its clarity. Glycerin acts as a humectant and is often used in cosmetics for that purpose. It is also used in foods and drugs.
Microbes Minute, simple, single-celled forms of life which are the cause of many infectious diseases.

Glycerine Soap Transparent soaps made in a similar manner to hot process soaps that also contain extra glycerine, alcohol and sugar.
Glycerin Dew: (Melt and Pour soap) The appearance of clear beads of liquid on the surface Melt and pour soap soap when exposed to air. Though unsightly, it has no effect on the quality or usefulness of the soap. Wrapping finished soaps with shrink or plastic wrap to create a barrier between the soap and air prevents this problem.
H
Hot Process Method A method of soap making that requires external heat to speed up the process of saponification.
HP Acronym for 'hot process' soap making.
Humectant A substance that attracts and aids absorption of moisture into the skin.
Hydrogenated Oil Unsaturated oils that have had hydrogen added to them to solidify them and make them more resistant to spoilage.
Hydro-sol Fragrant water left over from the steam distillation process. Commonly known as floral water.
Hydroscopic The tendency of a material to absorb moisture from air. Lye has hygroscopic properties.
I
INCI Name Acronym for International Nomenclature for Cosmetic Ingredients. This naming system, started by American Cosmetic, Toiletries, and Fragrance Association (CTFA), was initially used in the United States to standardize ingredient names for labeling purposes that the public would recognize. Since then, the European Union and Canada have adopted INCI nomenclature for their cosmetic ingredient labeling and in some cases, have applied their own naming conventions. Thus, the INCI name for a specific cosmetic in the United States may be different from the INCI name in Canada or in the European Union. INCI names for specific products are assigned by the International Nomenclature Committee, sponsored by the Personal Care Products Council (the new name of the CTFA). In order to get an INCI name assigned, the manufacturer must submit an application with the appropriate fee to the International Nomenclature Committee for review. INCI names for cosmetic ingredients and materials are published in the Cosmetic Ingredient Dictionary and Handbook, available from the Personal Care Products Council.
Infusion Very similar to making a tea. The botanical matter is steeped in water or oil for a length of time to extract it's beneficial properties.
Indehiscent (of a pod or fruit) not splitting open to release the seeds when ripe.
Iodine Value The measure of unsaturation (referring to presence of double bonds) in a fat or oil.
Insoluble A substance that is incapable of being dissolved. Fats and oils are insoluble in water.
Irritants Substances that cause inflammation or a painful/bothersome reaction to an allergy.

K
KOH The molecular formula for Potassium Hydroxide.

L
Lakes An oil dispersible combination of dyes and insoluble material that is man made. Lakes migrate in multilayered MP soap and are best used in single color soap pours.
Lard Fat that has been rendered from pigs (hogs).
Litmus paper A strip of paper containing a mixture of water soluble dyes that is used to indicate the pH level of a substance.
Lye Another name for Sodium Hydroxide.
Lye Discount: The word discount in this context means 'to reduce or use less'. With a lye discounted recipe, you are using less lye than is actually needed to saponify the entire amount of oils used in your recipe. This ensures that the final soap product does not contain any free lye and has extra oils to moisturise the skin. The usual amount of lye that is discounted tends to be around 5% - 10% but some recipes can go as high as 20%. ex. - on Soapcalc where is says "Super Fat/Discount %" (top right corner) you will see the default amount of 5%. If your recipe needs 100 grams of lye to fully saponify all of the oils, Soapcalc will calculate the recipe to have 95 grams of lye and this will leave some free oils in your final soap.

M
Materials Not Suitable for Contact with Lye Do not use these materials in contact with lye or lye-heavy soap: Aluminum, brass, bronze, chromium, iron, magnesium, tin, zinc, and most metals (other than stainless steel), and items made of metal and coated with Teflon. When lye reacts with these listed metals, hydrogen gas is generated which is extremely flammable and explosive. Never add sugar to lye solutions; lye may react with various sugars to generate carbon monoxide, which is a poisonous gas.
Materials Suitable for Contact with Lye Materials that are suitable for contact with lye at room temperature are high-density polyethylene (HDPE), polypropylene (PP), polyvinyl chloride (PVC), silicon rubber, stainless steel, glass, and porcelain. Stainless steel is most suitable for contact at elevated temperatures. Plastics soften at higher temperatures; run test for their suitability.
M & P Refers to melt and pour soap bases. Pre-made soap that can easily be cut up and melted to create decorative soaps. Contains lye like all soaps do and is available in various
Melting Point: The temperature at which a solid substance (oil for soap making) melts.
Mica A quartz-like mineral that sparkles due to optical reflection. The reflection can vary from a bright sparkle to a fine pearl depending upon the particle size. Colored micas are produced by coating mica with various dyes and pigments. In soapmaking, the light reflection is best viewed in transparent soaps. In opaque soap, the mica tends to provide only a dull color. If dyes have been used to color the mica, the color may migrate in MP soap.
Middle Note See Notes
Milled Soap: A commercial process that removes the glycerin from the soap, forms it into pellets, adds fragrance, and presses the soap into shape. A home soap maker can hand mill (re-batch) soap by grating it up, adding a small amount of liquid and applying heat until it reaches a translucent stage at which time the fragrance is added and the soap is molded.
Moisturizer: Moisturizers are delicate mixtures of ingredients (chemical or natural) specially designed to make the external layers of the skin softer and more pliable. Moisturizers increase the skin's water content by reducing evaporation.
Mold Soap molds are containers that hold the soap batter while it hardens. When hardened, the soap takes on the shape of the mold into which it the mixture is poured. Soap molds may be made out of a variety of substances, depending on the type of soap the artist is making and the intended life-span of the mold. For example, an empty milk carton may be used as a one-time mold, whereas a silicone liner in a wood mold may last for many years. Molds come in various shapes and sizes. Loaf mold: A long, deep three-sided mold, open on the top, to cast soap for slicing. Log Mold: A long, three-sided mold, open on the top, large enough to slice length-wise to produce several loaves for slicing. Vertical Log mold: A tall mold, the size of a single bar, which is poured from the top and then unmolded into a loaf to be sliced into individual bars. Slab mold: A shallow mold,the depth of one bar of soap. It is designed to be cut crosswise and lengthwise to product individual soaps. Tray mold: A single cavity mold that is meant to jcut into multiple full-size bars of soap. It is similar to a slab mold. Single mold: A single cavity, which when filled produces a single bar of soap. Single molds may be simple squares or circles or may have intricate designs. Sheet mold: A mold that has multiple cavities on one sheet, each producing one bar of soap. 3-D Mold: A 3-dimensional mold into which soap is poured to generate a three-dimensional shaped soap.
Mold Pitting A rough texture that develops on the interior surface of a molded plastic cavity due to the use of excessive fragrance or essential oil in the soap.
MSDS: Material Safety Data Sheet. A form containing data regarding the properties of a particular substance and is intended to provide workers and emergency personnel with procedures for handling or working with that substance in a safe manner.
MP Soap Base (MP) A man made soap specifically formulated to be heated, melted, and solidified without changing the soap base's original properties. MP soap base is water soluble and has a pH range of 8 to 10.
MSDS See Material Safety Data Sheet
N
NaOH The molecular formula for Sodium Hydroxide.
Natural A material that does not contain any synthetic substances.
Natron Natron is a naturally occurring mixture of sodium carbonate decahydrate (Na2CO3·10H2O, a kind of soda ash) and around 17% sodium bicarbonate (also called baking soda, NaHCO3) along with small quantities of sodium chloride and sodium sulfate.
Nutrient In soap making, a substance that contains properties that are beneficial for the skin.
Net Weight Weight of the contents in a container, not counting the weight of the container or lid.
Nonconforming Product: (Good Manufacturing Practices) A product in which one or more characteristics fails to meet specified requirements, deviates from quality requirements, or fails to conform to required standards.
Notes (fragrance) The order of volatile release of a fragrance into the air. Using the analogy to a musical chord, there are top, middle, and bottom fragrant notes that harmonize to create an accord. Top or head notes are the most volatile molecules of the fragrance that evaporate quickly and are the ones typically noticed first. They are usually light, refreshing scents that don't linger after they have been released to the air. Middle or heart notes are the scents that are noticed after the top notes are gone. These scents form the main theme, or heart, of the fragrance. Base notes are the scents from molecules that volatilize very slowly over a period of hours. By their nature, they provide a rich and deep lingering scent, forming the base of the perfume.
O
OHP Acronym for 'Oven hot process'. Hot process soap making that uses the oven as the heat source.
Organic A substance that at one time was alive and has not had chemicals or synthetic materials introduced to it.
Oils: Essential Oils Volatile oils extracted from plant matter by either distillation (steam or water), expression, or chemical solvents. Essential oils may be used to add fragrance to scented soaps.
Oils: Fixed Oils Refers to oils that can be raised to a high temperature without evaporating. Fixed oils (such as olive oil, palm oil, and coconut oil) are commonly used to make soap.
Oils: Fragrance Oils Also known as aroma oils and aromatic oils. These oils are blends of synthetic aromatic chemicals that may be diluted with a carrier such as propylene glycol, vegetable oil, or mineral oil. Fragrance oils may be used to add fragrance to scented soaps. pH
Overpour A secondary mass of soap that surrounds embed materials or embed soap.
P
pH pH is the measure of the acidity or alkalinity of a solution. A substance with a pH value greater than 7.0 (alkaline) are bases; less than 7.0 (acidic) are acids with 7.0 being neutral.
pH Strip Test Used to test for un-reacted lye in soap. pH strips may be purchased from most chemical supply companies, laboratory supply companies, and pool supply companies. pH strips used to test the pH of soap should include a scale from 7 to 14. To test with a pH test strip, put one gram of soap in 100-ml (100-g) of room temperature (25° F/77° C) water (having a neutral pH of 7), let the soap dissolve, and test with a pH strip by dipping it into the soapy water. Results for un-reacted lye in soap typically exceed 10 pH. Results for cured soap (no longer containing lye) may range from 8 to 10 pH. The reading of the pH test strip is dependent upon the interpretation of the soap maker and may be subject to error.
pH Tongue Test Used as a quick informal test for un-reacted lye in soap. Touch tongue to soap bar, or rub wet finger on soap and then touch finger to tongue. If a tingling, pinching, or burning sensation is felt, then the soap contains un-reached lye and is not ready for use. This test is greatly dependent upon the interpretation and sensitivity of the soap maker.
Photosensitizer A substance that causes skin to become hypersensitive in the presence of radiant energy and especially sunlight. Some substances which are photosensitizers are citrus oil and St. John's Wort oil.
Pigments A dry, insoluble colorant, usually as a fine powder, which is used to impart color. The most common pigments approved for use in cosmetic are iron oxides, ultramarines, and titanium dioxide. Cosmetic grade pigments are required by FDA to be man made (although they have the same chemical composition and thus are "nature identical." Pigments color soap by becoming suspended in the liquid soap and then being locked into place when the soap hardens. When added to liquid soap, the pigment should be well dispersed in a carrier liquid before being added, otherwise pigment particles may settle out, float to the surface, or clump. In soap, pigments do not migrate and remain colorfast. Many pigments, though not all, are opaque and can cloud clear MP soap. Titanium dioxide is the industry's most commonly used pigment to make MP soap base an opaque white.
Potassium Hydroxide KOH; CAS Registry Number: 1310-58-3; Molecular Weight: 56.11 g/mol. Also referred to as caustic potash, potash, potash lye, and potassium hydrate. It is a corrosive chemical that has a pH of 14, indicating it is a strong base. Potassium hydroxide is used in soap making to react with oils and fats to produce soap, frequently liquid soap.
Pouring Temperature: (MP) The temperature to pour melted MP soap into the mold.
Preservative A preservative is a natural or synthetic chemical that is added to products to prevent decomposition by microbial growth.
Order of Predominance The listing of items in decreasing order based on the amount present. In the ingredient declaration for cosmetics, ingredients are listed with the ingredient present in the highest percentage first, then the ingredient with the next highest percentage, and so on.
Q
Quality Assurance: (Good Manufacturing Practices) A set of activities or techniques whose purpose is to ensure that all quality requirements are being met. In order to achieve this purpose, processes are monitored and performance problems are solved.
Quality Requirement (Good Manufacturing Practices) A characteristic that a product must have. For example, quality requirements of soap could be defined as a soap that is free of excess alkali, has a stable shelf life, lathers and cleans adequately.
R
Rancidity Having an unpleasant, stale smell, as through decomposition, especially of fats and oils.
Re-batching: Also referred to as hand milling. A home soap maker can hand mill (re-batch) soap by grating it up, adding a small amount of liquid and applying heat until it reaches a translucent stage at which time the fragrance is added and the soap is moulded.
Recipe A written document which provides measurements for each ingredient and any necessary directions to correctly make the product. The measurements are typically given as percentages of the total weight of the batch or weight of each ingredient for a given batch size.
Refined Oils: Fats and oils that have had impurities filtered out.
Rendered Beef fat that has been heated and melted down to remove all impurities is said to have been 'rendered'.
Ricing Ricing occurs when a fragrance oil reacts with your base oils and produces little rice shaped grains in your soap batter. The soap batter will resemble rice pudding. When using a new fragrance, do not discount the water in your recipe and warm the fragrance oil (while still in its bottle) in a warm water bath before using it.
Room Temperature Method A soap making method similar to the cold process method. Instead of using heat to melt hard oils, the hot lye solution is used instead. No thermometers or external heat sources required.
RTCP: Acronym for 'room temperature cold process' soap making. The fats and oils are at room temperature when the lye solution is added.

S
Safety Equipment Safety equipment for making soap includes eye protection, a face shield, rubber gloves, and clothing to cover any bare skin that may be exposed to lye, including arms, legs, and feet. Ventilation equipment may be required when making large quantities of lye-water solution. Further safety equipment should include a smoke alarm, fire extinguisher, easy access to a telephone, a first aid kit, and easy access to fresh running water, such as from a sink or hose.
Saponification Value: Also SAP Value. The number of milligrams of KOH (potassium hydroxide) needed to saponify 1 gram of fat or oil. If sodium hydroxide is used in a recipe rather than potassium hydroxide, the SAP Value is multiplied by a conversion factor of 0.713, which is the ratio of NaOH molecular weight to KOH molecular weight.
Saponification: Saponification is the chemical reaction between an alkali (lye) and a fat or oil to form soap.
Saponification Calculator A tool used for calculating how much lye, oils and liquid are required to make a specific soap recipe. No matter what, even if you found someone else's tried and true recipe online, always run it through a reputable lye calculator to be safe
Sebum: The fatty substance secreted by the sebaceous glands of mammals that protects and lubricates the skin and hair.
Seize: A rapid solidifying of the soap while still in the soap pan. Usually caused by high amounts of stearic or palmitic acid, waxes or by some fragrance & essential oils.
Seize: A rapid solidifying of the soap while still in the soap pan. Usually caused by high amounts of stearic or palmitic acid, waxes or by some fragrance & essential oils.
Soap: The result of a chemical reaction between a lye solution (sodium hydroxide for bar soap or potassium hydroxide for liquid soap) and fats/oils. If it isn't made with lye, it isn't soap.
Soap Casting The art of creating handcrafted soaps using melt and pour soap base.
Soap Making Process: Cold Process: Cold process (CP) soap making is the process where lye is dissolved in water to form a solution. The lye-water solution is then added to melted fats and oils and constantly stirred or mixed with a hand blender. After trace is detected, scents, herbs, and/or colorants may be added to the soap batter. After trace but before seize, the cold process soap batter is poured into molds. The molds are usually insulated with blankets or towels. Within 24 hours, the soap batter hardens sufficiently to be removed from the mold and to be sliced into bars. Fresh bars of cold process soap must cure on drying racks for four to six weeks to allow the lye to completely saponify the fats and oils into soap. After four to six weeks of cure, cold process soap should be ready for use and should not contain any lye. This process is referred to as "cold" process soap making because no heat from an external source is added to the soap batter.
Soap Making Process: Hot Process: Hot process (HP) process soap making is the process where soap batter is made by mixing fats and oils with a lye-water solution until trace is achieved, just the same as in the cold process method of making soap. However, in the hot process soap making method, heat is added to the soap batter after trace by warming it on a stove or by pouring the soap batter into a crock pot. After approximately one hour, when all of the soap batter has boiled at a low simmer and has completed the gel phase, the soap is removed from the heat source and scents, herbs, and/or colorants may be added. The soap mass is then molded. Within a few hours, the soap may be unmolded, sliced into bars, and used. Hot process soap does not require any time to cure, to dry, or to harden.
Soap Making Process: Melt and Pour: The melt and pour (M&P) process of making soap involves using a pre-fabricated soap base, such as the soap base available from craft and hobby supply stores. These pre-fabricated soap bases often contain preservatives and stabilizers to provide a longer shelf life and superior meltability. The soap crafter cuts the soap base into cubes and melts the cubes in a double boiler or in a microwave. After the soap base is melted and is liquid, scents, herbs, and/or colorants may be added to the melted soap. Before the soap cools and hardens, it is poured into single-serving molds that are often specially designed shapes with meticulous details. Lye is not needed nor used in crafting melt and pour soaps.
Soap Making Process: Re-Batch Process The re-batch process (RB) of making soap involves using cold or hot process soap shavings. The cold process or hot process soap shavings are combined with a small amount of water and are heated in a double boiler for approximately one hour, until they are melted and dissolved to form a thick, bubbly, viscous mass of soap. The mass of soft melted soap is removed from the heat and scents, herbs, and/or colorants may be added. It is then spooned into molds to cool and harden. After a week, the soap is removed from the molds and sliced into bars. Often, re-batched soap requires several weeks to dry, depending on how much water was used to dissolve the soap shavings.
Soap Making Process: Warm Process For the warm process (WP) method of making soap, the soap maker begins by making soap with the cold process method but, instead of covering the molded soap with blankets, the warm process soap maker places the molds in a heated oven and incubates the soap at about 160° F for six hours. The molds are then removed from the heat source and allowed to cool slowly. After approximately 12 hours, the soap is removed from the molds and sliced into bars. Warm process soap is completely cured and free from lye as soon as it is cooled; however, warm process soap requires a few days to dry and harden. In warm process soap making, heat is added to complete the saponification of the soap, just as in hot process soap making. The difference is that hot process soap is boiled and warm process soap is not boiled, just warmed.
Soda Ash: A powdery white residue that sometimes forms on the surface of soap. Can be drying to the skin but is easily wiped off of the bar of soap with a damp cloth.
Sodium Hydroxide Sodium Hydroxide (lye) is another name for Caustic Soda. It is the alkali (base) used in bar soap making.
Sodium Cocoate Saponified coconut oil, the sodium salt of coconut oil.
Sodium Laureth Sulfate (Abbreviated: SLES) Used in soap and cosmetics as a foaming, cleansing, and emulsifying agent. It can be produced by the ethoxylation of sodium lauryl sulfate (SLS). Also known as sodium lauryl ether sulfate.
Sodium Palmate Saponified palm oil, the sodium salt of palm oil.
Sodium Stearate The sodium salt (soap) of the fatty acid stearic acid (found in palm oil and animal fats). It is used in soap and cosmetics as a cleansing and emulsifying agent.
Solar Sea Salts Sun evaporated sea salts from sea water, not mined or mechanically processed. This method preserves the natural mineral content.
Soluble: Capable of being dissolved or liquefied.
Solvent Extraction The process used to separate botanical matter from essential oils using solvents.
Sorbitol A molecule that is 6 carbons long with 6 hydroxyl groups, one hydroxyl group attached to each carbon. It is used in MP soap base to improve clarity and also acts as a humectant.
Steam Distillation: The process used to separate botanical matter from essential oils using steam.
Stearic Acid Stearic acid is a saturated fatty acid with an 18-carbon chain. It is a white, waxy solid at room temperature which has a melting point of 157°F (69.6°C). It may be added to all types of soap to create a harder bar. In MP soap base, it may cause cloudiness in the soap and affect lather, depending upon the amount and soap base being used.
Strigil an instrument with a curved blade used, especially by ancient Greeks and Romans, to scrape sweat and dirt from the skin in a hot-air bath or after exercise; a scraper.
Super-fatted The excess oils left unsaponified in the finished soap. This excess oil contributes to the moisturising qualities of soap.
Surfactant: A substance (like soap) that, when dissolved in water, lowers the surface tension of the water and increases the solubility of organic compounds.
Suspension Base (MP) A MP soap base that has been formulated to suspend items in it due to the addition of silica (silicon dioxide) which thickens the soap base.
Surfactant: A substance (like soap) that, when dissolved in water, lowers the surface tension of the water and increases the solubility of organic compounds.
T
Tallow: The fatty tissue or suet of animals (horse, cow and sheep).
Tare Weight Weight of an empty vessel or container. The tare weight is subtracted from the gross weight to get the net weight.
Titanium dioxide A very white pigment used in soap and cosmetics to make a white product. In MP soap, it is used to create an opaque white soap base.
Tocopherols: Any of a group of closely related, fat-soluble alcohols that are types of vitamin E, especially alpha-tocopherol.
Tongue Test A quick informal test for unreacted lye in soap. Rub wet finger on soap and then touch finger to tongue. If a tingling, pinching, or burning sensation is felt, then the soap is not ready for use. This test is greatly dependent upon the interpretation and sensitivity of the soapmaker.
Top Note See Notes
Trace: The point in soap making where the mixed lye and oils have combined to a thick pudding like substance. When drizzled on to itself, a trail is left.
Triglyceride A molecule that has three fatty acids attached to a backbone of glycerin. Commonly found in oils or fats, which may be solid or liquid at room temperature.
Turbinado Sugar Unrefined raw cane sugar, used in sugar scrubs and body polishes.
U
Unrefined The natural unaltered base, such as the oil obtained from the first pressing.
Unsaponifiables: The portion of oils that do not participate in the saponification process and remain in their natural state in the finished product.
Unsaturated Fatty Acid A fatty acid that has one or more double bonds connecting carbons to each other in its carbon chain. An unsaturated fatty acid that has only one double bond is known as monounsaturated. An unsaturated fatty acid that has more than one double bond is known as polyunsaturated.
Unscented Contains no added fragrance. See Fragrance Free.
V
Vegan: Not containing any animal parts or ingredients produced by animals.
Vegetable Shortening A solid fat made from vegetable oils. These oils are converted to a solid state through hydrogenation.
Viscosity: The resistance of a substance to flow. Honey is more viscous than water.
Volatile Oils: Oils that evaporate rapidly.
Volcano Effect: When making lye-water solution, if water is poured onto lye, the top layer of lye dissolves and releases heat. A hard crust forms on top as the temperature quickly rises and water evaporates. The lye on the bottom remains dry and un-dissolved. As more water is added to the lye mass, the top lye continues to dissolve and a thicker crust is formed and more heat is released. Pressure builds underneath the crust until enough pressure ruptures the crust and forces undissolved lye, partially dissolved lye, hot steam, and water to spray up, resembling a volcano. Therefore, never add water to lye; always add lye to water.
W
Waste Disposal: Proper waste disposal involves following the supplier's instructions found on the MSDS for each material. Also, soap makers may contact a recycling center to ask if it will accept old essential oils, fragrance oils, rancid base fats, fixed oils, curdled soap batches, and etc.
Water Soluble Dissolvable in water.
Wildcrafted Refers to herbs and botanicals grown in the wild without the use of pesticides or other chemicals.
Workplace Safety Workplace safety when making soap involves having ingredients properly labeled and stored, maintaining a clean, orderly, well-lit, and well-ventilated work area for making soap, restricting the access of children and pets to the storage and work areas, having easy access to personal protective equipment, a telephone, a fire extinguisher, and running water.
X
Xanathan Gum A derivative of corn sugar used as a thickening agent in cosmetics and foods.

Affiliate Disclosure: I am grateful to be of service and bring you content free of charge. In order to do this, please note that when you click links and purchase items, in most (not all) cases I will receive a referral commission. Your support in purchasing through these links enables me to keep Par Par Academy of Soaps & Cosmetics free, and empower more people worldwide to make soap safely and easily. Thank you!