History and Evolution of Candles
– The word candle comes from Middle English ‘candel,’ from Old English and from Anglo-Norman ‘candele,’ both from Latin ‘candēla,’ from ‘candēre’ to shine.
– Romans began making true dipped candles from tallow, beginning around 500BC.
– European candles of antiquity were made from various forms of natural fat, tallow, and wax.
– The earliest surviving candles originated in Han China around 200BC, made from whale fat.
– During the Middle Ages, tallow candles were most commonly used.
– Beeswax candles were expensive, but widely used for church ceremonies.
– In the mid-19th century, Joseph Morgan patented a machine for continuous production of molded candles, revolutionizing candle making.
– Candlemakers began using tightly braided cotton wicks that curl over as they burn, known as self-trimming wicks.
– James Young succeeded in distilling paraffin wax from coal and oil shales, making inexpensive candles of high quality.
– By the end of the 19th century, candles were made from paraffin wax and stearic acid.
– The candle industry declined rapidly with the introduction of kerosene, lamps, and the incandescent light bulb.
Uses and Applications of Candles
– Candles were commonly used for illumination before the invention of electric lighting.
– In the developed world, candles are now mainly used for aesthetic value, scent, emergency lighting, and religious or ritual purposes.
– There has been a significant increase in sales of scented candles in recent years, particularly during the COVID-19 pandemic and lockdowns.
– Candles were used as timekeeping devices, with time measurements marked along the wax.
– Candle clocks were made with weights set into the sides during the 18th century.
Candle Components and Production Methods
– Paraffin wax is the most common component of modern candles.
– Traditional candles were made from tallow, beeswax, or spermaceti.
– Other materials used for candle making include stearin, microcrystalline wax, gel, and plant waxes.
– The type of wax used affects the burn rate of the candle.
– Production methods for candles include extrusion moulding and melting the solid fuel.
– A candle wick works by capillary action, drawing the melted wax or fuel up to the flame.
– Commercial wicks are made from braided cotton.
– The characteristics of the wick, such as diameter and stiffness, affect how the candle burns.
– Wicks are often infused with chemicals to modify their burning characteristics.
Candle Characteristics and Flame Properties
– A modern candle typically burns at a steady rate of about 0.1g/min.
– The light produced by a candle is about 13 lumens, with a luminous efficacy of about 0.16 lumens per watt.
– The luminous intensity of a typical candle is approximately one candela.
– The hottest part of a candle flame is about 1,400°C (2,550°F), while the average flame temperature is about 1,000°C (1,830°F).
– The color temperature of a candle flame is approximately 1,000K.
– A candle flame has three to five regions or zones.
– The zones include the non-luminous base, the blue zone, the dark zone, the luminous zone, and the outer zone.
– The height of a candle flame is determined by the diameter of the wick.
– The brightest zone of the flame is not the hottest.
– The outer zone of the flame is light blue and reaches a temperature of around 1,400°C (2,550°F).
Safety, Environmental Impact, and Regulation
– Candles are a leading source of residential fires in the United States, causing injuries and fatalities.
– A candle flame that is longer than its laminar smoke point emits soot.
– Proper wick trimming can reduce soot emissions from candles.
– Liquid wax can cause skin burns, but the amount and temperature are usually limited.
– Glass candle-holders can crack due to thermal shock from the flame, so caution is advised.
– Candles emit volatile organic compounds (VOCs) into the environment, releasing carbon into the air.
– The combustion process of lighting a candle releases light, heat, carbon dioxide, and water vapor.
– Non-toxic candles have been developed to prevent the release of VOCs into the environment.
– Europe, the United States, and China have developed standards and regulations for candle safety.
– Candle accessories include candle holders, bobèches, candle followers, and snuffers. Source: https://en.wikipedia.org/wiki/Candle
A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat or a method of keeping time.
A person who makes candles is traditionally known as a chandler. Various devices have been invented to hold candles.
For a candle to burn, a heat source (commonly a naked flame from a match or lighter) is used to light the candle's wick, which melts and vaporizes a small amount of fuel (the wax). Once vaporized, the fuel combines with oxygen in the atmosphere to ignite and form a constant flame. This flame provides sufficient heat to keep the candle burning via a self-sustaining chain of events: the heat of the flame melts the top of the mass of solid fuel; the liquefied fuel then moves upward through the wick via capillary action; the liquefied fuel finally vaporizes to burn within the candle's flame.
As the fuel (wax) is melted and burned, the candle becomes shorter. Portions of the wick that are not emitting vaporized fuel are consumed in the flame. The incineration of the wick limits the length of the exposed portion of the wick, thus maintaining a constant burning temperature and rate of fuel consumption. Some wicks require regular trimming with scissors (or a specialized wick trimmer), usually to about one-quarter inch (~0.7 cm), to promote slower, steady burning, and also to prevent smoking. Special candle scissors called "snuffers" were produced for this purpose in the 20th century and were often combined with an extinguisher. In modern candles, the wick is constructed so that it curves over as it burns. This ensures that the end of the wick gets oxygen and is then consumed by fire—a self-trimming wick.
