Candle making is a complex craft to master, not only for its technical processes and the chemistry involved but also for the candle language.
Understanding the terminology used in candle making will enable you to discuss and debate with like-minded people. It will also help you to better understand the craft and its technicalities.
Some of the terminology used by candle makers can be quite confusing, especially when you’re just starting off. That is why our in house R&D team has compiled a long but easy to follow list of frequently used candle-making terms.
Terminology |
Meaning |
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Aftersmoke (Afterglow)
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When the wick continues to smoke or glow after you have blown out the flame.
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Aroma Compound
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A chemical that gives off a fragrance or odour, typically used in fragrance oils. Not to be confused with aromatic compounds, which contain a specific chemical sub-structure and have no particular association with the fragrance industry.
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Bridging
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The term used when a burning wick curls to such an extent that the tip of the wick makes contact with the surface of the melt pool.
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Burn Rate
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Also known as the hourly burn rate, this is the rate at which a candle burns, typically measured in grams per hour (g/h). To calculate the burn rate, a candle is weighed at the start of a burning period, then weighed again at the end of the burning period. The difference in weight represents the quantity of wax consumed. This weight is divided by the number of hours that the candle has burned to give the burn rate of the candle in grams per hour. For example, a candle that consumes 16.8g of wax over a 4-hour burning period will have a burn rate of 16.84 = 4.2
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Burn Test
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Informal term for process used to assess the burning performance of a candle.
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Burn Test Cycle
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The total time of a burning period and the pause after the burning period. The process of burning a full candle from start to finish consists of a series of burn test cycles.
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Burning Period
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The length of time between lighting a candle and extinguishing the flame.
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Candle Glass
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General term used to refer to the glass container in which a fragranced candle is made. Fragranced candle containers can be made in a variety of materials, including porcelain, bone china, metal and concrete.
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Cavity
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A gap or void that is formed inside or on the surface of a candle as the wax contracts during the cooling and curing process. Also known as a sink hole.
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Cold Throw
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The fragrance emitted from a fragranced container candle before the candle is lit.
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CLP
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General term for the label that displays the pictograms, signal words and standard statements for hazards etc. for candles and diffusers. The label is a legal requirement under the Classification, Labelling and Packaging (CLP) Regulation ((EC) No 1272/2008). The CLP label must be visible at the point of purchase, and it must be present on the box if the product is packed.
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Clubbing
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Build-up of carbon deposits on the candle wick, caused by incomplete combustion.
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Crystallisation
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The process where a poured candle mixture changes from a liquid to a solid mass which then “cures” to a stable form. See also curing time.
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Curing Time
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The period of time between pouring the candle and the candle reaching a state where it can be lit to give optimum performance. The curing time will differ for each wax/fragrance oil mixture. See also crystallisation.
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Double Pour
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A candle pouring technique in which a container candle is poured in two stages. Typically, the first pour will fill 70-90% of the candle. After cooling, when the wax has contracted, the second pour fills the candle to the desired level.
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Essential Oil
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An oil obtained by distillation of plant extracts, intended to capture the characteristic fragrance or “essence” of the plant. Essential oils are often marketed as blends of different oils.
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Flame Height
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The distance between the base of the flame and the top of the flame.
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Flash Point
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The flash point of a liquid (e.g., a fragrance oil) is the temperature at which the liquid gives off enough vapour that could cause it to ignite (albeit briefly) if exposed to a source of ignition.
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Fire Safety Test
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An informal term used for the series of tests and measurements performed on a candle to ensure that it meets the requirements of BS EN 15493:2019 (Candles - Specification for Fire Safety)
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Fragrance Oil
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The concentrated liquid fragrance that is added to scented container candles, wax melts and diffusers. See also essential oil.
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Fragrance Content
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The proportion of fragrance oil in the candle mixture. A fragrance content of 10% means that 10% of the total weight of the candle mixture consists of fragrance oil. The remaining 90% is the candle wax. For example, a 100g candle with a fragrance content of 10% contains 90g of wax and 10g of oil. Fragrance Content must not be confused with Fragrance Load.
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Fragrance Load
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The ratio of fragrance oil to wax. A fragrance load of 10% means that the weight of fragrance oil used in the candle will be 10% of the weight of wax used. For example, if a candle has a fragrance load of 10%, then a candle that uses 90g of wax will require 9g of fragrance oil to be added to the wax, because 9g is 10% of 90g. Fragrance Load must not be confused with Fragrance Content.
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Fragrance Notes
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A term used to describe the properties of a fragrance in words. There are three types of fragrance notes: Top Notes – these are the citrus or fruity notes. Top notes are volatile and give a powerful first impression of a fragrance. Middle Notes – also known as “heart” notes, these are floral, fruity or spicy components of a fragrance. Base Notes – these are the woody or musky notes that tend to hang around for a while.
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Frosting
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The “frosting” often referred to in candle-making is an example of “polymorphism”, where the solid mass of wax and fragrance oil changes into a different crystal form over time, causing a frost-like effect on the surface of the candle.
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Full Melt Pool (FMP)
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When the melt pool in a container candle covers the entire surface of the candle.
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Glass Adhesion
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A term used to describe how well a particular wax/fragrance mixture adheres to a candle glass. As wax cools, it contracts and pulls away from the glass leaving visible gaps on the inside of the glass. Plant waxes generally have better glass adhesion than mineral waxes.
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Hang-up
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The term used to describe the coating of wax left on the inner wall of a container candle as the candle burns down. See also tunneling.
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Hot Throw
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The fragrance emitted from a fragranced container candle when the candle is burning.
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IFRA
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International Fragrance Association
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IFRA Statement
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Informal name for the “Certificate of Conformity to IFRA Standards”. The IFRA Statement lists the maximum permitted levels of use of each fragrance oil in different product categories, e.g. candles, soaps, lotions.
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Jump Lines
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Also known as jump marks, these are a series of horizontal lines that can be seen on the inside of a clear candle glass when higher-melting waxes (typically mineral wax) have been used to pour a candle without pre-heating the candle glass. They are formed as the liquid wax solidifies on the cold surface of the glass.
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Melt Pool
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The area of liquid wax that forms around the wick(s) of a container candle as the candle burns.
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Mineral Wax
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Wax derived from distillation of petrochemical by-products.
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Mixing Temperature
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Informal term used to describe the recommended temperature for mixing fragrance oil or dye with candle wax to ensure that the fragrance oil or dye will dissolve in the wax.
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Mushrooming
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An extreme form of clubbing that can look like a small black mushroom.
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Natural wax
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A term often used to refer to plant wax.
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Nature Identical
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Used to describe essential oil ingredients that have been made in laboratories rather than extracted from plants. They are chemically identical to the actual molecules found in the plant-based essential oil, but the use of synthetic components ensures batch reproducibility and consistency.
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Overwicked
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When the wick in a candle causes a burn rate that is higher than expected or desired, the candle is said to be overwicked. See also underwicked.
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Paraffin Wax
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Another name for mineral wax.
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Plant Wax
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Wax derived from plant oils, e.g. coconut, rapeseed, soy.
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Pouring Temperature
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The recommended temperature for pouring a specific candle mixture into a candle glass.
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Pre-heating
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Heating of a candle glass before pouring the candle.
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Pull-away
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See glass adhesion
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Safety Data Sheet (SDS)
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A document that provides safety information about a substance.
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Secondary Ignition
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A flame other than that on the actual wick(s) on the candle.
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Single Pour
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This is when a container candle can be filled to the top in a single pouring process.
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Sink Hole
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See cavity
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Soot
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Black powdery carbon deposit caused by incomplete combustion of candle wax and fragrance oils.
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Soot Test
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An informal term used for the testing of a candles using specialised soot testing apparatus to ensure that it meets the requirements of BS EN 15426:2018 (Candles - Specification for Sooting Behaviour).
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Sustainer
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The metal support used to secure the wick to the base of the candle glass.
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Synthetic Fragrance Oils
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Fragrance oils that are developed by professional perfumers using organic chemical building blocks.
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Sweating
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Leaching of fragrance oil (or oil from the wax blend) from the candle onto the surface of the wax.
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Technical Data Sheet (TDS)
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Document provided by the supplier of a product or raw material that gives useful technical information about the product. While a Safety Data Sheet is intended to give safety information about a product, the role of a Technical Data Sheet is to advise the user on the specification of the product such as its physical properties, uses or origin.
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Tunneling
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This is an extreme form of hang-up, indicating that the candle may be under-wicked or that the wick is incompatible with the wax/fragrance oil mixture.
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Underwicked
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When the wick in a candle causes a burn rate that is lower than expected or desired, the candle is said to be underwicked. See also overwicked.
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Wick
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The part of a candle that is lit, creating a flame that melts more wax. The liquid wax is then drawn back into the wick via capillary action to fuel the flame and continue the burning process.
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Wick Claw
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A tool used to ensure that the candle wick is positioned in the centre of the candle.
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Wick Posture
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The shape adopted by the candle wick during the burning process. Good wick posture is required to keep the flame at a suitable height.
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Wick Stickum
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The double-sided sticky pad that is used to secure a wick sustainer to a candle glass.
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Wick Wax
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The wax that is used to coat the candle wick.
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Wick Yield
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A measure of the thickness of a candle wick. The units used are grams per metre (g/m) or metres per kilogram (m/kg). These values refer to the unwaxed wick. For example, a wick with a yield value of 1.50 g/m means that a 1 metre length of raw wick weighs 1.50 grams. The m/kg system is basically an "inverted" version of the above. A wick with a yield value of 665m/kg means that 1 kg of raw wick will stretch to a length of 665 metres.
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