A good candle is pleasing both functionally and aesthetically. Its performance should correspond to its purpose, so it's not possible to apply the same qualities and standards to all candles. Also, the conditions a candle is exposed to during storage or use may affect its qualities - an excellent candle stored improperly may be ruined; or the same candle with great burning qualities will perform poorly if burned incorrectly. Likewise, candle performance may be enhanced with the use of certain accessories and good care.

Candles are usually burned for light, to create atmosphere, for religious functions, to add fragrance to an area, as part of celebrations, or to repel insects. Selecting the best candle for your purpose is important.

Basically, a good candle:
· Burns without smoking or dripping
· Retains its shape during burning
· Does not have any off odor or oily smell
· Burns with an even flame, usually no more than 1 1/2" high
· Emits a pleasant fragrance (if scented) when burning
· Does not have any visible separation of wax and oil
· Has the wick centered or evenly spaced for multiple wicks
· Has good weight for its size
· Is packaged with the name of the manufacturer and burning instructions

Good candles for adding light without fragrance are tapers, which are usually unfragranced. Standard tapers are usually between 3/4" and 7/8" in diameter, and those sizes will fit in almost all standard taper holders. Tapers usually range between 6" - 14" tall, though I have seen them up to 36" long - very dramatic for special occasions, but be careful how you store them since they will bend and break easily at that length! The tops of taper candles may vary - some are rounded, others milled to a decorative shape - but this should not affect the performance. Sometimes the bottoms may be grooved to allow easier fitting in holders. Tapers may be made by various methods - molded, dipped or drawn.

A good taper candle should burn without smoking or dripping, with a quiet flame about 1" high. The wick may curl slightly during burning (this means the wick has been "pickled") and should not form a black glob (also known as a "devil's head") on the end. Straight sided tapers will burn slightly longer than those that taper inward, simply because they have more wax. Standard straight-sided paraffin wax tapers of good quality will burn almost 1" of the length per hour. Beeswax tapers have a longer burn time. Tapers should be stored flat so they do not bend. Taper candles are adversely affected by heat and direct sunlight, which may cause color fading and bending. Tapers should not be burned in a drafty area or they will drip and flicker, also known as "guttering". Taper performance may be enhanced by the use of hurricanes to protect against drafts; tapers should be extinguished by using a snuffer to avoid any smoke from the glowing wick.

Tea Light Candles are also widely used to add light without fragrance. Tea lights may be pressed wax or poured wax, and are usually in a small metal or plastic cup. A good tea light should burn with a strong flame, without smoking, drowning out or the wax spilling out of the cup. The wax should not have any "off" oily smell. Tea lights are great where multiple flames are desired in a small area, especially where you wish to show off the holder and not the candle itself. The quality of a tea light is almost always related to its cost - cheap tea lights usually burn poorly and quickly; the better tea lights (usually from Europe) may burn up to six hours.

Fragranced Candles are very popular, and usually used indoors to add fragrance to the home. Fragranced candles are usually made in the form of votives, pillars or container candles. A good fragranced candle should smell just as good burning as it does when it's not. This sounds obvious but sometimes certain fragrance mixtures don't burn well, particularly citrus types. A fragranced candle emits its fragrance from the pool of molten wax that is formed during burning. The bigger the pool of molten wax, the more fragrance emitted. The fragrance used must be compatible with the type of wax used and properly blended during the manufacturing process. If not, the wax and fragrance may separate, with drops of oil forming on the surface; or bumps may form on the surface ruining the appearance of the candle. This is called "outgassing". There are so many variables in fragrance/wax combinations that it is absolutely necessary for the manufacturer to do product testing for compatibility & performance prior to production.

In short, a good fragranced candle emits a pleasant fragrance when burning, does not have oily residue or bumps, does not smoke when burning.

A good pillar candle burns to the edges without dripping, consuming itself completely. The wick should be centered to ensure even burning. If it is a multiwick pillar, the wicks should be evenly spaced. It should not "blow" out the sides when burning. It should sit level, not lopsided. It should have a burn time in proportion with the size of the candle. It should burn with a quiet flame no more than 1 1/2" high. The wick should not accumulate large sooty deposits, and should have a metal "sustainer" to hold it upright during burning. Pillars may be molded using poured (liquid) wax, compressed using powdered wax (which is then overdipped) or extruded, which may also be overdipped to achieve a smooth finish. Compressed and overdipped pillars usually do not burn as long or as well as poured or extruded pillars. Poor quality pillars may even be made with whipped (aerated) wax with a thin shell of solid wax - these will seem lightweight for their size and will not burn well at all.

Pillar candles are usually used for decorative purposes in addition to burning, so the overall appearance is important to the quality. A good pillar candle is colored throughout instead of overdipped - the thin overdip layer chips easily exposing the white wax below. Pillar candles are a good opportunity to explore different surface textures, color schemes, embedded materials (such as herbs, dried fruits, coffee beans, sea shells, etc), and other decorative finishes. Pillar candles are very effective in groups of different sizes, on trays or holders.

A good votive candle burns completely, with a pleasant fragrance (if scented). The votive candle should not drown out or smoke. Most votives burn better in a votive holder. Some votives will liquefy completely and must be burned in a holder. The wick should be held in place with a metal "sustainer" so it does not fall over as it burns down. Since votives are usually burned in a holder, sometimes the surface appearance is not considered important and is not an indication of the quality of the votive candle.

A good container candle uses a vessel or container that is compatible with the wax and number of wicks. Large container candles should have multiple wicks to use all or the majority of the wax. Some container candles may become hot during burning, especially glass or metal containers. A good container candle should have some protection on the bottom - such as feet, cork or felt pads - to avoid damage to surfaces. Most container candles are fragranced, and should form a large pool of molten wax when burning. The wicks should be affixed firmly to the bottom of the container using a sustainer, and the wax should not drop out of the container.