Glossary of Terms
The term “acceleration,” or, more accurately, “accelerating trace,” in soap-making refers to speeding up of the process known as “Trace.”
The acid value is the number of milligrams of potassium hydroxide necessary to neutralize the free acids in 1 gram of sample. With samples that contain virtually no free acids other than fatty acids, the acid value may be directly converted by means of a suitable factor to percent free fatty acids.
AOCS is an acronym standing for The American Oil Chemists' Society, "...a global professional scientific society for all individuals and corporations with interest in the fats, oils, surfactants, detergents and related materials fields. The Society produces the Official Methods and Recommended Practices of the AOCS. Currently in it's 6th Edition, this document includes over 400 analytical methods critical to processing, trading, utilizing, and evaluating fats, oils, and lipid products.
The Autoignition Temperature of a substance is the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. The temperature at which a substance will ignite decreases as the pressure increases or oxygen concentration increases.
“Boiling Point” is the temperature at which the vapor pressure of a liquid equals atmospheric pressure or at which the liquid changes to a vapor. If a flammable material has a low Boiling Point, it indicates a special fire hazard.
A “Botanical Name” is a formal name conforming to the International Code of Botanical Nomenclature (ICBN). The purpose of such a formal name is to have a single name worldwide for a particular plant or plant group.
“CAS” is an acronym for the Chemical Abstract Service, a division of the American Chemical Society. A “CAS Number” (or “CAS Registry Number”) is a unique numeric identifier for chemical substances found in the CAS Registry (the "Registry"). The CAS Registry is the largest and most current database of chemical substance information in the world, containing more than 32 million organic and inorganic substances and nearly 60 million sequences. The Registry covers substances identified from the scientific literature from 1957 to the present, with additional substances going back to the early 1900s. The CAS Registry contains a wide variety of substances, including the world's largest collection of Organic compounds, Inorganic compounds, Metals, Alloys, Minerals, Coordination compounds, Organometallics, Elements, Isotopes, Nuclear particles, Proteins and nucleic acids, Polymers, and Nonstructurable materials (UVCBs).
The IFRA Code of Practice is a comprehensive document that supports our commitment to provide products that are safe for use by the consumer and to the environment. The Code of Practice applies to the manufacture and handling of all fragrance materials, for all types of applications and contains the full set of IFRA Standards. Abiding by the IFRA Code of Practice is a prerequisite for all fragrance supplier companies that are members of IFRA (either directly or through national associations). The majority of client companies (including producers of toiletries and household products) expect their fragrances to comply with IFRA Standards as set out in the Code. Amendments to the Code, if required, are issued annually, based on new scientific developments. These contain either new usage restrictions or revisions of existing usage restrictions. The IFRA Code of Practice is distributed worldwide and is in the hands of all member associations and their member companies, including governmental regulatory bodies and many other stakeholders. It is also available to all here.
This method measures the resistance of the test sample to crystallization and is commonly used as an index of the winterization and stearin removal process. Also see Cloud Point.
The cloud point of fatty acids is the temperature at which the clear fatty acid becomes hazy (or "cloudy"), due to the crystallization of higher melting components, when the product is cooled under specified conditions.
CTFA is an acronym for the American Cosmetic, Toiletry and Fragrance Association. Originally, the Toilet Goods Association (TGA), the CTFA, through it's approximately 600 member companies, “...provides a complete range of services that support the personal care products industry’s needs and interests in the scientific, legal, regulatory, legislative, and international fields.”
As defined in the Federal Food , Drug and Cosmetic Act under Section 201(i), the term "cosmetic" means... “(1) 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 (2) articles intended for use as a component of any such articles; except that such term shall not include soap”.
As used in reference to the transport of Hazardous Materials, the term “Dangerous Goods” shall refer to any material having a Flashpoint at or below 60.5 degrees Celsius (141 degrees Fahrenheit).
The density of a material is defined as its mass per unit volume. Mathematically, density is expressed as
“Dewaxing” is the process of removing wax from a base oil to improve low temperature properties, especially to lower the cloud point and pour point.
“Discoloration” in soap-making, for our purposes, describes the alteration of hue or appearance from the otherwise inherent color of the soap.
“EINECS,” is an acronym referring to The European Inventory of Existing Commercial Substances. An “EINECS Number” is the seven-digit code that is assigned to chemical substances that are commercially available within the European Union.
An essential oil is a concentrated hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile, ethereal oils or aetherolea, or simply as the "oil of" the plant from which they were extracted, such as oil of clove. An oil is "essential" in the sense that it carries a distinctive scent, or essence, of the plant. Essential oils do not as a group need to have any specific chemical properties in common, beyond conveying characteristic fragrances. Essential oils are extracted from their plant hosts using a variety of methods including distillation, expressing, and solvent extraction (see "Extraction Methods for Plant Oils for further information). They are used in perfumes, cosmetics, soap and other products, for flavoring food and drink, and for scenting incense and household cleaning products. Various essential oils have been used medicinally at different periods in history. Medical applications range from skin treatments to remedies for cancer, and are often based on historical use of these oils for these purposes. Such claims are now subject to regulation in most countries, and have grown more vague to stay within these regulations. Interest in essential oils has revived in recent decades with the popularity of aromatherapy, a branch of alternative medicine which claims that the specific aromas carried by essential oils have curative effects. Oils are volatilized or diluted in a carrier oil and used in massage, diffused in the air by a nebulizer or by heating over a candle flame, or burned as incense, for example.
Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemically, fats are generally triesters of glycerol and fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure and composition. Fats form a category of lipid, distinguished from other lipids by their chemical structure and physical properties. This category of molecules is important for many forms of life, serving both structural and metabolic functions. They are an important part of the diet of most heterotrophs (including humans). Fats or lipids are broken down in the body by enzymes called lipases produced in the pancreas. Examples of edible animal fats are lard (pig fat), fish oil, and butter. They are obtained from fats in the milk, meat and under the skin of the animal. Examples of edible plant fats are peanut, soya bean, sunflower, sesame, coconut, olive, and vegetable oils. Margarine and vegetable shortening, which can be derived from the above oils, are used mainly for baking. These examples of fats can be categorized into saturated fats and unsaturated fats.
“Fatty Acids” are defined as any of a class of aliphatic monocarboxylic acids that form part of a lipid molecule and can be derived from fat by hydrolysis; fatty acids are simple molecules built around a series of carbon atoms linked together in a chain of 12 to 22 carbon atoms. In soap-making, “Fatty Acids” refers to the various base oils used including, but not limited to, Apricol Kernal Oil, Avocado Oil, Canola Oil, Castor Oil, Coconut Oil, Hemp Oil, Olive Oil, Palm Kernal Oil, Palm Oil, Rice Bran Oil, Safflower Oil, Soybean Oil, Sunflower Oil, Sweet Almond Oil, and the like. Free Fatty Acids ("FFA") are fatty acids that are not attached to other molecules. FFA's may result from the breakdown of a material, such as triglyceride, into its components.
“FCC,” an acronym meaning Food Chemicals Codex, is the accepted standard for defining the quality of food-grade additives and chemicals in terms of identity, strength, and purity based on the elements of safety and good manufacturing practices. The FCC project is an activity of the Food and Nutrition Board of the Institute of Medicine, supported by the U.S. Food and Drug Administration. Following the passage of the Food Additives amendments to the federal Food, Drug, and Cosmetic Act in 1958, the Food Protection Committee of the Food and Nutrition Board of the National Academy of Sciences-National Research Council, received requests from its Industry Liaison Board and other sources to undertake a project to produce a Food Chemicals Codex. The First Edition of the resulting Food Chemicals Codex, which was published in 1966, was limited to chemicals that are added directly to foods to achieve a desired technological function. Succeeding editions upgraded the specifications for these substances and added specifications for substances that come into contact with foods and some that are regarded as foods, rather than as additives. To date, five editions of the Food Chemicals Codex (1966, 1972, 1981, 1996, and 2003) have been published.
The term “Flammable” is defined differently by various U.S. Government agencies. The U.S. Occupational Health and Safety Administration (OSHA) defines a flammable liquid as “any liquid having a flash point below 100 deg. F. (37.8 deg. C.), except any mixture having components with Flashpoints of 100 deg. F. (37.8 deg. C.) or higher, the total of which make up 99 percent or more of the total volume of the mixture. Flammable liquids shall be known as Class I liquids.” OSHA divides flammable (and combustible) liquids into several classes. Refer to 29CFR1910.106 for further information. See also “Dangerous Goods” for information on the shipment of Hazardous Material.
“Flashpoint” is the lowest temperature at which a flammable liquid gives off sufficient vapor to be ignitable. This does not necessarily mean that the vapor will ignite.
Fragrance Industry Ingredients The Fragrance Industry, through its representative organization, the International Fragrance Association ("IFRA") has published a Fragrance Industry Ingredients List used in consumer goods by their customers worldwide for the purposes of transparency. IFRA’s Safety Program establishes safe use for fragrance materials. The IFRA Code of Practice and the IFRA Standards are based on risk assessments and may prohibit or restrict the use of fragrance materials in consumer goods if there is concern for human health or the environment. The Code of Practice and the Standards must be adhered to by all IFRA affiliated member companies. Adherence is enforced through the IFRA Compliance Program.
An “FO,” or fragrance oil, are blended synthetic aroma compounds or natural essential oils that are diluted with a carrier like propylene glycol, vegetable oil, or mineral oil. Also known as aroma oils, aromatic oils, and flavor oils, FO's are used in perfumery, cosmetics, flavoring of food, and in aromatherapy.
It is impossible to describe a fragrance according to its components because the exact formulas are kept secret. Even if the formulas are known, the ingredients are often too numerous to provide a useful classification. On the other hand, it is possible to group fragrances into scent families and describe them through the notes that appear as they slowly evaporate.
“GRAS” is an acronym meaning “G”enerally “R”egarded “A”s “S”afe.
“HLB” is an acronym meaning Hydrophilic-Lipophilic Balance, a system for measuring the degree to which a non-ionic surfactant is either hydrophilic or lipophilic, determined by calculating values from different regions of the molecule, as described by the system's inventor, William C. Griffin. The HLB system facilitates optimum performance of emulsion applications including combining dissimilar oils; formulating water-in-oil emulsions; wetting powders into oils; formulating oil-in-water emulsions; and formulating detergent solutions. The HLB System works in accordance with the formula: HLB = 20 * Mh / M Mh is the molecular mass of the hydrophilic portion of the Molecule, and M is the molecular mass of the whole molecule, The HLB value can be used to predict the surfactant properties of a molecule:
Hazardous Materials Identification System (HMIS) HMIS (Hazardous Materials Identification System) is a numerical hazard rating that incorporates the use of labels with color-coded bars as well as training materials. It was developed by the National Paint & Coatings Association (NPCA) as a compliance aid for the OSHA Hazard Communication Standard. For additional information and use guidance, click here.
“Hydrosol,” also sometimes referred to as floral water, hydrolate, herbal water, essential water, and herbal distillates, are aqueous solutions or colloidal suspensions of essential oils usually obtained by steam distillation from aromatic plants. These herbal distillates have uses as flavorings, medicine and in skin care. Hydrosols are produced in the same manner as essential oils. However, the essential oil will float to the top of the distillate where it is removed, leaving behind the watery distillate. For this reason perhaps the term essential water is more descript. In the past, these essential waters were considered a byproduct of distillation, but now are considered an important co-product. Hydrosols contain many of the beneficial elements from essential oils but in a less concentrated, safer form. Besides aromatic chemicals, these distillates also contain many of the plant acids making them skin friendly. With a pH of 5-to-6 they are great to use as facial toners. Cosmetics and toiletries makers are finding many uses for hydrosols. They can be used alone as toners or room sprays. Distillates are also used as flavorings and curables. Popular hydrosols include rose water, lavender water, lemon balm, clary sage and orange blossom water. The use of hydrosols in cosmetics is increasing. Because hydrosols are produced at high temperatures and are somewhat acidic, they tend to inhibit bacterial growth. They are not however sterile. They are a fresh product, like milk, and should be kept refrigerated.
“Hydroxyl Value” is a measure of hydroxyl (univalent OH) groups in an organic material.
International Code of Botanical Nomenclature (ICBN) The International Code of Botanical Nomenclature (ICBN) is the set of rules and recommendations dealing with the formal botanical names that are given to plants. Its intent is that each taxonomic group ("taxon", plural "taxa") of plants has only one correct name, accepted worldwide. The value of a scientific name is that it is a label: it is not necessarily of descriptive value, or even accurate.
International Fragrance Association (IFRA) IFRA, the International Fragrance Association, was established in 1973 and is the official representative body of the fragrance industry worldwide. It's main purpose is to ensure the safety of fragrance materials. This is accomplished through implementation of a list of approved fragrance ingredients employed under a strict Code of Practice.
“INCI” is an acronym for International Nomenclature Cosmetic Ingredient and is a system for naming cosmetic ingredients. It is a multilingual, multinational system based on Latin. Ingredient listing on cosmetic product, using the INCI system, is required by law in several countries around the world. The INCI system was designed in 1973, and developed over a period of more than 25 years. It was created by the CTFA's International Nomenclature Committee and the INCI system forms the basis of the ICI Dictionary and Handbook. The ICI Dictionary and Handbook presents, in detail, the bulk of INCI names juxtaposed with their corresponding empirical chemical formulas, technical/trade names, Chemical Abstracts System numbers (CAS No.), or alternate numbers and this allows for the unambiguous identification of ingredients. The current INCI nomenclature system is distributed in multiple volumes and encompass all ingredients and classes of ingredients that are used in cosmetic products. The primary objective of the INCI system is to standardize the technical names of ingredients found in cosmetics and to keep the need for alternative labeling names to a minimum. The current INCI dictionary contains approximately 12,000 INCI names and the corresponding 55,000 trade and technical names. The INCI system contains all that is required for naming and labeling ingredients used by the cosmetics industry and has become necessary and sufficient in the cosmetics field. For the purpose of identifying chemical compounds, which are used as ingredients in cosmetics, INCI ingredient names are predominantly based upon the terminology created by the International Union of Pure and Applied Chemistry (IUPAC). INCI names are a contraction of IUPAC names, which are based on Latin and are recognized as multilingual. IUPAC was developed by an international, scientific and non-governmental body that was formed in 1919, by chemists from both industry and academia. This organization has united the international chemical sciences community (academic, industrial and public sector) by creating a common language for chemistry. IUPAC is recognized as the world authority on chemical nomenclature and terminology.
“Iodine Value” is a measure of the unsaturation of fats and oils and is expressed in terms of the number of centrigrams of iodine absorbed per gram of sample (% iodine absorbed).
“JCID” is an acronym for the Japanese Cosmetics Ingredients Directory, a publication of the Japanese Cosmetics Ingredients Association.
“KOH Value” is a value that, when multiplied by the amount of the item used (expressed in the unit of measure shown), will result in the amount of potassium hydroxide (KOH) required to be combined with the item to saponify them (see also SAP Value and NaOH Value).
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The main biological functions of lipids include energy storage, as structural components of cell membranes, and as important signaling molecules. Although the term lipid is sometimes used as a synonym for fats, fats are a subgroup of lipids called triglycerides. Lipids also encompass molecules such as fatty acids and their derivatives (including monoglycerides, diglycerides, triglycerides and phospholipids), as well as other sterol-containing metabolites such as cholesterol. Although humans and other mammals use various biosynthetic pathways to both break down and synthesize lipids, some essential lipids cannot be made this way and must be obtained from the diet.
“Lovibond Color” refers to the calibrated output measurement of color using the Lovibond comparator, a colorimeter (a color-measuring device) invented by Joseph Williams Lovibond in the 19th century, and currently manufactured by The Tinometer Ltd.
“Melting Point” is the temperature at which a solid becomes a liquid at standard atmospheric pressure.
“Miscibility” is the ability or tendency of one liquid to mix or blend uniformly with another and form a single homogeneous phase. Alcohol is miscible in water; gasoline and water are immiscible. When two substances are immiscible they will form separate phases when mixed; the best known example is oil and water. See also Solubility, often used in the same sense in reference to liquids.
“NaOH Value” is the value that, when multiplied by the amount of the item used (expressed in the unit of measure shown), will result in the amount of Sodium Hydroxide (NaOH) required to be combined with the item to saponify them (see also SAP Value and KOH Value).
“Neat” means to apply undiluted, directly on skin.
An oil is any substance that is liquid at ambient temperature, is hydrophobic but soluble in organic solvents, and can be traced back to it's organic sources. Oils also have a high carbon and hydrogen content and are nonpolar substances. Examples are essential oils, petrochemical oils, and vegetable oils.
The “Oil Stability Index” is a quality assurance test method for determining the induction period of an oil. All oils and fats have a resistance to oxidation which depends on the degree of saturation, natural or added antioxidants, prooxidants, or prior abuse. Oxidation is slow until this resistance is overcome at which time oxidation accelerates and becomes very rapid thereafter. This length of time before this rapid acceleration of oxidation is the measure of the resistance to oxidation and is commonly referred to as the "induction period." In this test a stream of purified air is passed through a test sample of oil or fat which is held in a thermostated bath. The effluent air from the oil or fat test sample is then bubbled through a vessel containing deionized water. The conductivity of the water is continually monitored. The effluent air contains volatile organic acids, swept from the oxidizing oil, that increase the conductivity of the water as oxidation proceeds. Formic acid is the predominant organic acid formed. The conductivity of the water is monitored by a computer or strip chart recorder. OSI is defined as the point of maximum change of the rate of oxidation. This time-based end point may be determined by a computer that can calculate the maximum of the second derivative with respect to time, or by a slope-change algorithm, which is similar to detecting the onset of peaks for integration of GLC chromatograms. The end point may be approximated by using other methods. One commonly used approximation is a graphic method in which tangents are drawn manually (see Fig. 2). The OSI may be run at temperatures of 100, 110, 120, 130, and 140°C. Because by its nature this analysis has this temperature flexibility, all OSI results specify the OSI time, with the analysis temperature reported immediately after (for example, “OSI, 11.7 hours at 110°C”).
An oil's characteristics straight out of the bottle are rarely identical in a manufactured end-product. Thus, a fragrance must be advance-tested to learn how it will change during and after being subjected to the manufacturing processes of the various end-products in which it will be used. Part of our service is to perform some of these tests and provide reasonable, if limited, performance guidance to our customers. To that end, we test all of our fragrance oils (except Value-Line Fragrances), primarily in cold-process ("CP") soap. We are also testing an increased number of our fragrances in soy wax candles and, sometimes, in a cream or lotion base as well. We chose CP soap as our primary test product because the chemical and environmental impact of the saponification process is the toughest on fragrances. CP soap testing is performed using several standardized recipes, including an all-veggie recipe (palm, coconut, shea, olive, etc) and a tallow recipe (palm kernel, shea, rice bran, etc). Finished CP soap test products are allowed to cure for a minimum of 6 weeks, some for much longer. Fragrance oils are then evaluated. We rate each fragrance for it's key CP soap characteristics including... We follow a standardized 5-point scale for grading scent strength in CP soap and soy candle testing. Specific terms are used to identify the finished product scent performance characteristics as follows:
[2] Only basic elements (lye, oils, water) are used in these recipes (no special additives, colorants or the like). User Note: our commentaries are intended to provide only limited guidance for use and results may vary according to individual recipe.
“Peroxide Value” is a measure of the extent of fat or oil oxidation of a substance by measuring the amount of peroxides present. Peroxides are intermediate compounds formed during the oxidation of lipids which may react further to form the compounds that can cause rancidity.
“pH,” an acronym meaning potential of hydrogen, is the logarithm of the reciprocal of the measure of hydrogen-ion concentration in gram-atoms per liter of a solution. The pH Scale provides a measure, on a scale from 0 to 14, of the acidity or alkalinity of a solution; where 7 is neutral (e.g., water), below 7 is increasing acidic, and above 7 is increasingly alkaline (basic).
“Pour Point” is the lowest temperature at which an oil or other liquid will pour under prescribed conditions when it is chilled without disturbance at a fixed rate.
“Refractive Index” is a measure of how much the speed of light (or other waves, such as sound waves) is reduced by passing through a medium. Used as one of the primary objective test procedures to determine the quality of essential (and other oils). Deviations from established (published) data are indicative of adulteration.
Research Institute for Fragrance Materials ("RIFM") RIFM was formed as a nonprofit corporation in 1966 to gather and analyze scientific data, engage in testing and evaluation, distribute information, cooperate with official agencies and to encourage uniform safety standards related to the use of fragrance ingredients. The RIFM Database of flavor and fragrance materials is the largest available worldwide, classifying more than 5000 materials. The database is available online, 24/7, by subscription. RIFM's Database also houses an online collection of Flavor/Fragrance Ingredient Data Sheets (FFIDS) from 1985-present. FFIDSs are issued to assist with compliance for U.S. OSHA's Hazard Communication Standards and the European Commission's Dangerous Substances Directives. All of RIFM's research is reviewed by an independent Expert Panel, an international group of dermatologists, pathologists, toxicologists environmental and respiratory scientists that have no commercial ties to the fragrance industry. The Expert Panel advises RIFM on its strategic approach, reviews protocols and evaluates all scientific findings. Their conclusions form the basis for the Standards set by the International Fragrance Association (IFRA). RIFM's staff scientists reach out to the international fragrance industry about progress in environmental testing, respiratory research and skin sensitivity testing through electronic bulletins, publication of the latest results in peer-reviewed scientific publications and by in-person presentations at professional societies, individual companies, government agencies, and industry committee and association meetings. RIFM is relied upon as the most comprehensive resource for safe use and exposure information on fragrance materials. RIFM is the cost effective solution for safety research and testing. RIFM delivers well-documented conclusions from comprehensive analysis that translates into enhanced Product Management for its members, resulting in safer and more life enriching products for the consumer. Membership in RIFM is open to all companies that manufacture, sell, distribute or engage in business related to the fragrance industry for at least one year.
“Saponification” is the alkaline (or base-) hydrolysis of fats which produces an alcohol (glycerol), and the sodium or potassium salt of a carboxylic acid, more commonly referred to as soap. The bases most commonly used are sodium hydroxide (NaOH), used to form a hard soap; or potassium hydroxide (KOH), used to form a soft soap. The acids most commonly used are vegetable oils and/or animal fats, which are fatty esters in the form of triglycerides. Through the process of heating and agitation, the alkali breaks the ester bond and releases the fatty acid and glycerol.
“SAPonification Value” is the amount of alkali necessary to saponify a definite quantity of a substance. It is commonly expressed as the number of milligrams of potassium hydroxide (KOH), or Sodium Hydroxide (NaOH), required to saponify 1 gram of the substance.
“Scent Strength” refers to the relative power of a scent compared to other fragrances within a given class of aromatic oils. It is generally inappropriate to compare fragrances of different classes. Thus, you wouldn't compare a light, ethereal scent to a sharp, fruity one; etc., etc.
“Shelf Life” is the recommended length of time, from the date of manufacture or shipment, that a product can be relied upon to retain it's quality characteristics, under the specified storage conditions, after which time the product can become unsuitable for use or consumption. A product's shelf life or safe storage time of a product, is affected by a number of variables, including intrinsic parameters (such as pH and moisture content) and extrinsic parameters (such as environmental factors).
“Solubility” is the ability of a material to dissolve in water or another liquid. Solubility may be expressed as a ratio or described using words such as insoluble, very soluble or miscible (see Miscibility).
“Specific Gravity” (or “relative density”) is the ratio of the density (mass per unit volume) of a substance to the density of a given reference material (specific gravity usually means relative density with respect to water). If a substance's specific gravity is < 1.00 then it is less dense than the reference; if > 1.00 then it is denser than the reference; and if exactly equal to 1.00 then the densities are the same. With water as the reference, specific gravities of < 1.00 will float in water and those > 1.00 will sink. Temperature and pressure must be specified for both the sample and the reference. For the purposes of all specifications on this website, the pressure is always assumed to be 1 atmosphere (14.696 psi).
“Stability” is the ability of a material to remain unchanged in the presence of heat, moisture or air. An unstable material may decompose, polymerize, burn or explode under normal environmental conditions. Any indication that the material is unstable gives warning that special handling and storage precautions may be necessary.
“Trace,” is the first and most critical milestone in the Saponification process. The start of Trace, called “Light Trace,” is the first visual evidence of the chemical reaction. It is evident by the slight thickening of the acid-water-base mixture (which will look smooth and glossy) to a consistency sometimes described as a “thin custard.” The mixture will be still quite “liquidy” at this point. Some soap-makers prefer to pour their soap mixture into molds at Light Trace. The stage of “Full Trace,” sometimes called “Heavy Trace,” is reached when the soap mixture has thickened considerably. To test for Trace, dip a spatula or spoon into the soap mixture and dribble a bit of it back into the mixing pot. If it leaves a visual trace of the dribblings behind, then Trace has been reached and, hence, it's name. Light Trace occurs when the trail, though evident, disappears quickly back into the mixture and, Heavy Trace, when the trail lingers longer. With the use of different fats and mixtures requiring varying heating and mixing cycles, etc., it is impractical to subscribe to a more accurate definition than the visual/physical attributes described herein.
In analytical chemistry, a “trace element” is an element in a sample that has an average concentration of less than 100 parts per million (i.e., 0.01%) measured in atomic count, or less than 100 micrograms per gram. Of significant concern are those trace elements which can cause ill effects to organisms and the environment including, especially, heavy metals. Living organisms require varying amounts of heavy metals. Iron (Fe), cobalt (Co), copper (Cu), manganese (Mn), molybdenum (Mo), and zinc (Zn) are required by humans. Excessive levels can be damaging to the body. Other heavy metals such as mercury (Hg), plutonium (Pu), and lead (Pb) are toxic metals and their accumulation in the bodies of animals over time can cause serious illness. Certain elements that are normally toxic can be beneficial for certain organisms and under certain conditions. Examples include vanadium (V), tungsten (W), and even cadmium (Cd). Heavy metals occur naturally in the ecosystem with large variations in concentration. In modern times, anthropogenic sources of heavy metals, i.e. pollution, have been introduced to the ecosystem. The determination of trace elements in edible oils is important because of both the metabolic role of metals and possibilities for adulteration detection and oil characterization. Heavy metals pollution has become of considerable concern since some of them are dangerous to health and/or the environment (e.g., Hg, Cd, As, Pb, Cr), some may cause corrosion (e.g., Zn, Pb), and some are harmful in other ways (e.g., arsenic may pollute catalysts). Some of these elements are necessary for humans, though in minute amounts (Co, Cu, Cr, Ni), while others are carcinogenic or toxic, affecting, among others, the central nervous system (Hg, Pb, As); the kidneys or liver (Hg, Pb, Cd, Cu); or skin, bones and/or teeth (Ni, Cd, Cu, Cr). In testing for these "heavy metals," solvent-diluted oils are analyzed for the elements by direct aspiration. The most commonly used techniques for the determination of metals in oil samples are inductively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectrometry (AAS).
Unsaponifiable matter are those substances frequently found dissolved in fatty acids and drying oils which cannot be saponified by caustic treatment, but which are soluble in normal fat solvents. Included are the higher aliphatic alcohols, sterols, pigments, and hydrocarbons.
Vegetable fats and oils are lipid materials derived from plants. Physically, oils are liquid at room temperature and fats are solid. Chemically, both fats and oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure. Many different parts of plants may yield oil. The melting temperature distinction between oils and fats is imprecise, since definitions of room temperature vary, and typically natural oils have a melting range instead of a single melting point since natural oils are not chemically homogenous. Although thought of as esters of glycerin and a varying blend of fatty acids, fats and oils also typically contain free fatty acids, mono- and di-glycerides, and unsaponifiable lipids. Vegetable fats and oils may be edible or inedible. Examples of inedible vegetable fats and oils include processed linseed oil, tung oil, and castor oil used in lubricants, paints, cosmetics, pharmaceuticals, and other industrial purposes.
“Viscosity” is the measure of a fluid's resistance to flow. Low viscosity fluids flow easily (alcohol, water); high viscosity fluids pour slowly (molasses). See Absolute Viscosity and Kinematic Viscosity below. Absolute Viscosity. Kinematic Viscosity.
“Volatility” is a measure of how quickly a substance forms a vapor (i.e., evaporates) at ordinary temperatures.
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