What is it called when a candle melts down on one side but not the other?

The phenomenon you’re describing is called tunneling. It occurs when a candle burns down in a narrow tunnel through the center, leaving a significant amount of unmelted wax along the sides of the container. This can be frustrating for candle enthusiasts, as it reduces the overall burn time and can leave a lot of wasted wax.

Causes of Tunneling

Several factors can contribute to tunneling:

  • Improper first burn: The first burn is crucial for establishing an even melt pool. If the candle isn’t burned long enough on the first use, the wax may not melt all the way to the edges, creating a “memory” that the candle will follow in subsequent burns.
  • Drafts: Air currents can cause the flame to flicker and melt the wax unevenly.
  • Wicks that are too small: A wick that is too small may not be able to melt the wax fast enough, leading to tunneling.
  • Fragrance oils: Some fragrance oils can solidify at a higher temperature than others, making them more prone to tunneling.
  • Container shape: Narrow or deep containers can make it more difficult for the wax to melt evenly.

Preventing Tunneling

There are several things you can do to prevent tunneling:

  • Burn your candle for 3-4 hours on the first use: This will ensure that the wax melts all the way to the edges of the container and creates an even melt pool.
  • Trim the wick regularly: A wick that is too long can cause the flame to become too large and melt the wax unevenly. Trim the wick to 1/4 inch before each use.
  • Burn your candle in a draft-free environment: Drafts can cause the flame to flicker and melt the wax unevenly.
  • Choose candles with the right wick size: The wick should be large enough to melt the wax evenly but not so large that it creates a large flame.
  • Consider using a candle warmer: Candle warmers melt the wax without a flame, which can help to prevent tunneling.

Fixing Tunneling

If your candle has already started to tunnel, there are a few things you can do to try to fix it:

  • Wrap the candle in aluminum foil: This will help to reflect heat back onto the candle and melt the wax more evenly.
  • Use a heat gun: A heat gun can be used to melt the wax around the edges of the tunnel. Be careful not to overheat the wax, as this can cause it to smoke or catch fire.
  • Cut away the tunneled wax: If the tunnel is very deep, you can carefully cut away the tunneled wax with a knife. Be careful not to damage the wick.


Tunneling is a common problem with candles, but it can be prevented and fixed with a few simple tips. By following the advice in this guide, you can enjoy your candles for longer and get the most out of your investment.

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When you’re first starting out, candlemaking terminology can be intimidating and confusing. We hope that this useful glossary of terms will help you get started with candlemaking more easily. This list will expand your candle vocabulary even if you’re a seasoned candle maker!

Download our Printable Candle Making Glossary for easy reference!

Additive: A material mixed into your wax to alter its appearance, functionality, or other characteristics Common additives include candle dye and stearic acid. Additives also include things like mica, glitter, tiny gemstones, and plants. But it’s not advised to use these kinds of additives with container candles. For wax melts and specific pillar candle designs, materials like mica, glitter, plants, stones, and other items work well.

Base Note: The element of a fragrance that establishes its aroma Base notes, in contrast to top and middle notes, are typically richer, warmer scents like sandalwood, amber, musk, and vanilla. Base notes tend to be larger, heavier molecules. As a result, when you smell a fragrance, they usually register last. Once the top notes and middle notes of a fragrance have started to fade, the base notes are detected.

Bottom Note: Another term for base note. See above.

Burn Rate: How quickly a candle burns through its wax Usually, this is expressed in grams of wax consumed every hour. The candle’s total burn time is calculated using the burn rate. Depending on the kind of wax, wick, fragrance, container, and other elements, the burn rate will change. See also: Rate of Consumption (ROC).

Burn Session: The process of burning a candle for up to four hours in order to assess the performance of the fragrance, wax, and wick collectively. This step is an important part of testing candles. Also referred to as a “burn cycle. ”.

Burn Time: The amount of time a candle will burn after it is lit. This is typically indicated on the label of the candle to inform customers of the total number of hours the candle can be lit during its lifetime.

Carbon Buildup: Black carbon residue starts to accumulate on the wick of a candle when it uses more wax than it can burn. As a result, the wick ends up with a ball that resembles a mushroom. Because of the way it looks, carbon buildup is also called “mushrooming.” This could happen if you use an excessively large wick.

Chandler: A person who makes candles.

Clogged Wick: When debris, impurities, or other non-burnable materials are drawn into a wick, it can become “clogged.” Non-burnable materials never have enough fuel in the wick to keep the flame burning properly. The flame will eventually starve and burn itself out. When coloring your candle with additives like mica or crayons, wicks frequently become clogged. Excess carbon can also clog a wick. Use only colorants made especially for dying candles to prevent clogs.

Cold Throw: The scent of a candle before it is lit is referred to as its “cold throw.” Since the scent of a candle makes an initial impression on customers, having a strong cold throw is crucial.

A container candle is one that is created inside of a container, like a ceramic, metal, or glass jar. Making container candles involves simply adding wax to a container.

Core: The center of a candle wick is referred to as the “core” in candlemaking. Certain wicks are composed of paper or natural fibers, while others have zinc cores. Generally speaking, cored wicks are more rigid than coreless wicks.

Coreless: “Coreless” candle wicks are those that don’t have a metal or fiber core. These wicks are hollow or tube shaped. The majority of coreless wicks are made to bend at the tip when they burn, placing the wick’s tip inside the area of the flame that burns the hottest. Many coreless wicks are considered “self-trimming. LX, CD, and CDN wicks are a few types of coreless wicks.

Curing is the process of allowing a poured wax to melt or to sit for a while. Curing a candle enables the fragrance to completely infuse and bind to the wax as well as the wax to fully solidify. Your candles will burn with a greater scent throw if you allow them to cure. Furthermore, allowing your candles to cure will give you a more accurate indication of how the wick functions. If you test your candles right after pouring them, the wax might not be sufficiently solid to give you a reliable impression of how a customer would find them to burn.

Cure Time: The amount of time after pouring that candles or wax melts are allowed to sit The ideal cure time depends on the wax used. Paraffin wax candles should cure for at least 2 days. Soy wax candles should cure for 1-2 weeks. Candles made of coconut wax or other natural waxes should be given at least two weeks to cure. These guidelines apply to wax melts as well as candles.

A double boiler is an apparatus consisting of a pot (like a melting pot for wax) placed inside a larger pot or sauce pan that is filled with water. You can heat the double boiler on a hotplate or stovetop. The wax melts when the water in the sauce pan boils or simmers. This method is preferable to melting wax over direct heat.

Double Wicking: The practice of lighting a candle with two wicks. When creating a candle in a large container, where a single wick would not be able to achieve a full melt pool, double wicking is appropriate. The two wicks in a double-wick candle are positioned equally apart from the container’s edge and from one another. You will divide the container’s diameter in half to get the right wick size. Next, select wicks that match half of the diameter. For example, in a 4. If the container has a diameter of 5″, you should select wicks suitable for a 2 25” container. The wicks ought to be positioned so that the flames stay away from the container’s edge.

When a wick is immersed in a puddle of melted wax, it drowns. Whenever the wick is too small for the container, drowning out frequently happens. In this case, the wick covers itself with melted wax and extinguishes itself because it cannot absorb enough of the melted wax to stay lit.

An aromatic substance that is extracted from a plant’s leaves, flowers, seeds, bark, roots, or rind is called an essential oil. Essential oils are extracted by distilling or mechanically pressing plant materials, and they are extremely concentrated oils. Essential oils are best used in bath and body products. They are typically not made with solvents that make them smell strongly when burned, making them inappropriate for use with candles and wax melts.

Flame Height: The height at which a lit candle appears An ideal flame height is ½” to 2” in length. The ideal flame height for smaller candles is typically between ½” and 1″. It is dangerous to burn a candle in an excessively large flame.

The temperature at which a substance’s vapor, like fragrance oil, could catch fire in an enclosed vessel if it came into contact with an ignition source

Flickering: A candle’s flame may dance, jump, or flicker when it is not burning at a steady pace. This happens when something stops the wick from consuming the melted wax or the oxygen flow. Candles frequently flicker due to gusts of wind or other variations in airflow, but contaminants in the melt pool can also cause flickering when they prevent the flame from consuming wax or oxygen. Steer clear of additives that could clog the wick in order to stop flickering (see “clogging” above).

Fragrance Load: The fragrance-to-wax ratio. A candle’s fragrance load is usually expressed as a percentage. As an illustration, a candle may have an 8% fragrance load, which indicates that 8% of the total weight of the ingredients is made up of fragrance. Most waxes can handle a fragrance load of 8-12 percent.

Fragrance Notes: An essential oil’s constituent parts that define its aroma Fragrances have top, middle and bottom notes. Because top notes are softer, they are perceived first and fade more rapidly. Middle notes are sensed as the top notes disappear. Base notes are sensed last, and linger the longest. Many complex notes are used in each fragrance. A wide variety of notes are combined to create distinctive fragrances.

Fragrance oil is a fragrant oil composed of both natural and synthetic components. To add more complexity, fragrance oils can also be combined with a variety of essential oils. Fragrance oils may be skin-safe, meaning that bath and body products can use them, depending on the ingredients used. Solvents and additional ingredients are used in the formulation of fragrance oils to provide a strong scent that can be added to candles, wax melts, soap, and other items.

Frosting: An organic crystallization that happens naturally in vegetable waxes, especially soy wax Temperature changes that happen when melting and cooling wax to make candles cause frosting. Frosting is only decorative and has no bearing on the functionality of your candle. It is almost impossible to prevent frosting in soy candles. Candle dye tends to make frosting more noticeable, but it can also show up on white candles. Candle frosting typically becomes more noticeable as time passes and the wax continues to solidify and crystallize naturally.

Glass Adhesion: This describes wax’s capacity to adhere to a candle container’s interior. Wax with strong glass adhesion will stick tenaciously to a container’s walls. Wax may leave behind damp areas if it doesn’t stick to a container’s walls entirely. These are purely decorative and have no bearing on how well a candle works. See more under “wet spots. ”.

When the candle burns, a rim of wax called “hang up” remains around the container’s edges. Some hang-up wax is normal on your first few burns. But, you can wind up with a candle that tunnels if, by the third burn, the melt pool does not reach the jar’s edges (see definition below). You might need to use a larger wick size to solve the problem if the wax hang-up is not resolved by the third burn.

The aroma emitted by a burning candle is known as the “hot throw.” When a candle has a strong hot throw, it smells strongly when it is lit. Allow your candle to burn for at least two hours (do not let it burn for longer than four hours at a time) in order to accurately assess its hot throw.

Jump Lines: Also called chatter lines or stuttering. These are the visible lines that show up outside a pillar candle or along the sides of a candle container. Jump lines are usually horizontal. These lines appear when wax pours and sets up too quickly. By pouring your wax at a warmer temperature or preheating the container with a heat gun, you can prevent jump lines.

Melt Point: The temperature at which heated wax starts to liquefy

Melt Pool: When a candle is lit, a liquid wax layer forms around the wick. If a candle is not properly wicked, it can be determined by looking at the size of the melt pool. The melt pool in a properly wicked candle might not reach the sides of the container until the second or third burn session is finished. If you never achieve a full melt pool (i. e. The wick might be too small if the melt pool never reaches the container’s edges. On the other hand, if the melt pool does reach the container’s edges during your initial burn, the wick might burn too hotly during subsequent burns.

Middle Note: An element of a scent that defines its aroma Middle notes are sensed after the top notes burn off. Middle notes tend to have a softer, warmer scent. It’s common to classify fruity, floral, herbal, and spicy flavors as middle notes.

Mix Temperature: The temperature at which fragrance, colorants, or other additives are added to melted candle wax The ideal mix temp will vary depending on your wax. For 100% soy wax, 185 degrees F is ideal. Generally speaking, you want your wax to reach 200 degrees F (or even 220 degrees F) before adding fragrance to coconut blends.

Mushrooming: This is the formation of a mushroom-shaped ball from carbon buildup on the end of a burning wick. A mushrooming effect could mean that the wick size was incorrect. But using excessive amounts of fragrance or other additives can also cause mushrooming. Try using a smaller wick or reducing your fragrance load a little bit to avoid mushrooming.

Neck: The wick sustainer tab’s tube-shaped portion, which keeps the wick in place. Most necks are about 6mm in length. To keep the wick firmly in place after it has been inserted, the neck is typically crimped.

Out of Bottle (OOB): The aroma emitted by a fragrance as soon as it is opened. A fragrance’s out-of-bottle scent can help you decide if you like it or not. But when fragrance is added to wax, it frequently smells different. Therefore, you shouldn’t rely on the out-of-the-bottle scent entirely. A fragrance’s hot and cold throws may also have distinct scents. To find out if you like the scent in wax, it’s a good idea to make a small batch of melts.

A freestanding candle that doesn’t need a container is called a pillar candle. Pillar candles are made from harder waxes, often 100% paraffin. The majority of pillar candles have a cylindrical shape, but virtually any shape can be created with the use of molds.

Pour temperature refers to the temperature at which melted wax is poured into your candle mold or containers from your melt pot. When making candles, the pour temperature is something you should pay close attention to. It helps to know what pour temperature worked well for you in the past so that you can achieve the same results with subsequent batches of candles. The temperature in your workspace will affect the ideal pour temperature. We recommend starting at 145 degrees F. To determine the perfect temperature for your process, you can experiment with changing the temperature by 5 to 10 degrees.

Power Burning: When a candle is burned for longer than four hours at a time This can be risky because, over the course of a four-hour burn, containers could get too hot. But occasionally, candle makers like to perform power burns to simulate how their clients might use their candles. Candlemakers can feel more secure about clients who might leave their candles burning for an extended amount of time if a candle burns safely for four hours during testing.

Primed: When a wick is covered with wax before being used to make candles, it is referred to as “primed.” Since most premium wicks will come already primed, you won’t need to prime your own wicks. Primed wicks tend to burn better than raw, uncoated wicks. If you were to buy a roll of uncooked wick material, you might want to prime it by dipping the wick into paraffin or another hard wax. This should improve the burn.

Rate of Consumption (ROC): An equation that you can use to calculate how quickly a candle will burn and how many hours it will take to burn completely out of use

You will need to weigh the completed, unburned candle on a scale to determine its initial weight in order to compute the rate of consumption. After that, light the candle and let it burn for two to four hours, or however long you want it to (don’t let it burn for longer than four hours at a time). Extinguish the candle and let it cool. Then weigh the candle again. To determine the ROC, solve the following equation: hourly burn rate = (original weight – post-burn weight) ÷ hours burned

The length of time the candle will burn can be estimated with a single ROC calculation. All you need to know is the total amount of ounces or grams of wax you used to make the candle. As an alternative, you can conduct more burning sessions to ascertain how long the candle will burn for in total. This takes more time, but may be more accurate.

Relief holes are holes pierced into a candle’s surface on purpose to keep air pockets from forming when the candle cools down after pouring. These are typically not required for “single-pour” waxes. When the wax begins to harden or form a skin on top of your candle, you can poke relief holes into the surface of your candle. After the wax solidifies, you can pour it again. The relief holes will then be filled in.

Repour: Also referred to as a “second pour. To remedy problems like sink holes or wax shrinkage, pour more melted wax into a container candle. This is known as a replenishment. Repouring a candle smooths out imperfections.

Scent Throw: A phrase used to characterize the potent scent of a wax tart or candle. This phrase can be used to describe both the scent of an unlit candle (cold throw) and a lit candle (hot throw).

Pouring a second layer of wax into a container candle after the first layer has solidified is known as “second pouring.” Generally speaking, second pours are only necessary if the candle has sink holes or the wax has shrunk. There’s no need for a second pour if the wax is smooth on top.

Candle waxes that don’t need a second pour or refill are referred to as single pours. Single pour waxes are preferred because they typically yield satisfactory results after just one pouring attempt and don’t typically require additional steps to create visually appealing candles.

Sink Hole: A pit that appears on the wax’s surface when a candle is poured and starts to solidify Sink holes tend to form around the wick. A sink hole typically indicates that the hard wax has an air pocket trapped beneath its surface or that the wax cooled too quickly. Sink holes can be filled by drilling relief holes and pouring again (refer to the definitions above).

Candles with smooth wax surfaces that resemble glass are referred to as “smooth tops.” Most candlemakers strive for smooth tops because they enhance the visual appeal of their candles.

Snuffer: An instrument for neatly extinguishing a candle without using air Since candle snuffers don’t disturb the wax in the melt pool, they are frequently preferable to use. Bell snuffers are a useful addition to include with your candles if you sell them.

Sooting: When incomplete combustion takes place, black smoke is released from a candle wick. Black stains on the edges of your candle container can be caused by soot. Additionally, depending on where a candle is lit, soot may get on walls. When a candle is lit in a drafty space, soot may form. Moreover, it might indicate that the candle is not properly wicked or that there are too many additives in it. e. too much fragrance, dye or other additives).

When pouring a candle, a stabilizing bar is a tool used to hold the wick centered and in place. Usually composed of metal, stabilizing bars are fully reusable. While some candle makers center wicks with popsicle sticks or other similar devices, metal stabilizing bars are more user-friendly and efficient.

Stearic Acid: An additional ingredient used to harden wax Stearic acid is useful for enhancing the texture of the wax in container candles as well as helping pillar candles maintain their shape. Stearic acid is said by some candle manufacturers to prolong the life of candles and create more evenly burning, smoke-free flames. Also referred to as Stearine.

Sweating: Tiny, moist droplets that appear on a candle’s surface after it has been lit. Sweat may be a sign that the candle was moved from a very cold room to a very warm one too quickly, without allowing the wax to gradually adjust to the temperature change. Another indication that too much fragrance oil was used on a candle is sweat. The excess fragrance may “sweat” out of the candle’s surface if you used more fragrance than the wax can hold.

Tart: Fragrance-infused, wickless wax that, when warmed, releases a fragrant scent throughout a room Tarts can be made in clamshell containers or small molds.

Tart Warmer: A device used to heat wax melts. Tart warmers are usually glass, ceramic or metal. The heat generated by an electric tart warmer’s lightbulb melts the wax. In other tart warmers, the wax is heated using a tealight candle.

Phase of Testing: The process of lighting a candle to assess its performance prior to selling or presenting it as a gift. You should check to see if the candle is appropriately wicked during the testing process. You can also use testing to find out how long a candle will burn in total (see Rate of Consumption above).

Throw: A word used to express how far a candle can spread its aroma A candle with “good throw” has the ability to scent an entire space, even an entire home. A candle with a poor throw will not effectively diffuse scent. Throw can also mean the aroma that a candle emits both when it is lit and when it is not (see definitions for hot and cold throw).

Noteworthy: An element of a fragrance that establishes its aroma Top notes are the lightest, and therefore are sensed first. Top notes provide an initial impression of a fragrance’s aroma. Top notes fade more quickly than middle and bottom notes due to their lighter molecule composition.

Top pouring is the process of adding more wax to a container candle after it has solidified. Also referred to as a “second pour. Top pouring can be useful for removing any flaws that might show up on the wax’s surface once it starts to solidify.

Tunneling is the result of a candle never reaching a fully melted pool. The wick will form a tiny melt pool that only goes deeper and deeper into the candle rather than melting the wax uniformly across the surface of the candle. This will eventually result in thick, unmelted wax walls around the candle’s edges. The longer the candle is lit, the less efficiently tunneling wicks will burn. These candles won’t seem to burn as brightly either because the wax tunnel will conceal the flame. It is very difficult to fix tunneling once it begins. Your candle may eventually tunnel if it doesn’t reach a full melt pool on the second or third burn. Consider using a larger wick.

UV Stabilizer: A compound that helps lessen the possibility of discoloration or color changes in your wax when it is exposed to UV light

Vessel: Another term for a candle container. Vessels may include glass, ceramic or tin containers.

Votive: a short, tiny candle that is usually lit in an ornamental vessel Votives, in contrast to tealights, are typically not self-contained in their own cup. Votives are typically made using a mold and are free-standing candles. Although the candle can be burned directly, most people like to place them in vibrant glass containers.

Vybar: An ingredient that can aid in a candle’s ability to retain fragrance oil With the help of this addition, you might be able to use larger fragrance loads without affecting how well your candles work. Vybar can also increase the opacity of wax.

Wax Melt: Also referred to as a wax tart. Scent-infused wax is used to create wax melts, which melt and diffuse fragrance throughout a space. A wax warmer is needed to heat wax melts.

Wet Spots: Tiny air pockets that could develop between a container candle’s wall and the wax These air pockets appear “wet,” but are not actually liquid. Moisture stains are purely aesthetic; they have no bearing on how candles burn. Wet spots are essentially unavoidable. Candles from well-known brands can develop wet patches as well. Wet spots are more apparent if you use clear containers. Utilizing solid or opaque containers is the only method to totally prevent them.

Wick assembly is the procedure for making a ready-to-use candle wick. Wick assembly entails priming the wick by applying wax to a spool of raw wick material, cutting the wicks to size, and then affixing wick tabs. This word can also refer to a wick product that is prepared for use in candlemaking when used as a noun.

Wick Bar: A bar that is used to secure a wick during the pouring of wax. See “Stabilizing Bar” above.

Wick Clip: A metal component that helps secure a wick and fastens it to a container’s bottom. Generally speaking, the term “wick clip” describes parts for wooden wicks. A wick clip is used to insert a wood wick, securely pinching and holding it in place. Next, using a glue dot, secure the wick clip to the bottom of a candle container. Clips may also be referred to as sustainer tabs.

Wick Down: Choosing a wick that is smaller in size. When you make a candle with a wick that burns too hot or creates a flame that is too big, you must wick it down.

A metal part called a wick pin is used to center pillar candles’ wicks precisely. A pillar mold’s wick pin is a component that makes a hollow cavity for the wick to go through. After the wax solidifies in the mold, it is taken out. The hole left by the wick pin can then be filled with a wick.

Wick Tab: A metal component that secures a wick Wick sustainer tabs are often rounded with a short, hollow “neck” that firmly holds the wick in position. Wick tabs make it easier to secure the wick to a candle container’s bottom. This term and “wick clip” are frequently used interchangeably. ”.

A specific type of scissors used to trim wicks to the proper length is called a wick trimmer. The flat surface of wick trimmers helps catch the cut wick piece and prevent it from falling into the candle. Shop our selection of candle wicks trimmers.

Wick Up: Choosing a wick that is larger in size. When you make a candle with a wick that burns too slowly or doesn’t produce a large enough flame, you must wick it up.

Wicking: Choosing the right wick for your candle depends on a number of variables, including the kind of wax, size of the container, and amount of fragrance it contains.

Wickless: Wickless candles or wickless products are any scented wax that is not equipped with a wick. Wax melts are an example of a wickless product. Wickless candles, which resemble container candles but lack a wick, are another product of certain candlemakers. These candles are warmed by a heat lamp or a specialized candle warming plate.

The candlemaking community uses a lot of acronyms, just like any other craft. The following are some of the most often used acronyms by candle makers:

  • FO: Fragrance Oil
  • EO: Essential Oil
  • CT: Cold Throw
  • HT: Hot Throw
  • ROC: Rate of Consumption. See definition above.
  • OOB (OOTB): Out-of-the-bottle. This is the scent that a fragrance has when it is first taken out of the bottle and applied to wax.
  • IFRA: International Fragrance Association. A self-regulated, global organization that governs the fragrance industry. It establishes safety guidelines for both the components of fragrances and the uses for which they can be applied.
  • SDS: Safety Data Sheet. A list of each substance’s characteristics as well as the physical, health, and environmental risks connected to any chemicals used in the final product Many chemical compounds used in fragrances are regarded as “trade secrets” and might not be fully listed on an SDS. But any related safety issues and precautions will still be mentioned.
  • MSDS: Manufacturer’s Safety Data Sheet. This is the same as an SDS document. The terms are often used interchangeably.

Where Does the Candle Wax Go?

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