Where Does the Wax Go When Candles Burn?
Nowhere-it simply changes into other substances. That is what burning does to everything. The moment you put a match to the wick, you start a change in the candle by turning the solid wax into a liquid. The liquid wax rises to the wick by an irresistible process called capillarity, the simplest example of which is the way blotting paper soaks up ink or water. Then the liquid wax changes into a gas which burns–a chemical reaction which releases energy in the form of light and heat.
The presence of the gas can be demonstrated by blowing out the candle immediately holding a lighted match an inch or so above the wick. The inflammable vapor instantly catches fire and the candle lights up again without the match having actually touched the wick. Other changes are taking place while the candle burns. The wax is a complex chemical compound of carbon and hydrogen. The process of burning is simply the combination of the wax with the oxygen in the air. If you put a jar over the candle, it will quickly use up the oxygen and go out.
During the time the candle burns, the carbon joins with the oxygen in the air and makes carbon monoxide and carbon dioxide, and the hydrogen combines with the oxygen to produce water. While all these changes in the substance of the candle are taking place, the candle, of course, is becoming shorter. But it is not “going” anywhere. Its materials are simply changing into other substances.
The earliest surviving candles originated in Han China around 200 BC, and were made from whale fat. European candles of antiquity were made from various forms of natural fat, tallow, and wax. In Ancient Rome, candles were made of tallow due to the prohibitive cost of beeswax. It is possible that they also existed in Ancient Greece, but imprecise terminology makes it difficult to determine.
In the Middle Ages in Europe, tallow candles were the most common candle. By the 13th century, candle making had become a guild craft in England and France. The candle makers (chandlers) went from house to house making candles from the kitchen fats saved for that purpose, or made and sold their own candles from small candle shops. Beeswax, compared to animal-based tallow, burned cleanly, without smoky flame. Rather than the foul and terrible odor of tallow, it emits a fresh smell. Beeswax candles were expensive, and relatively few people could afford to burn them in their homes in medieval Europe. However, they were widely used for church ceremonies.
In the 18th century, spermaceti, oil produced by the sperm whale, was used to produce a superior candle. Late in the 18th century, colza oil and rapeseed oil came into use as much cheaper substitutes. The manufacture of candles became an industrialized mass market in the mid 19th century. In 1834, Joseph Morgan, a pewterer from Manchester, England, patented a machine that revolutionised candle making. It allowed for continuous production of molded candles by using a cylinder with a moveable piston to eject candles as they solidified.
This more efficient mechanized production produced about 1,500 candles per hour. This allowed candles to become an easily affordable commodity for the masses. Candlemakers also began to fashion wicks out of tightly braided (rather than simply twisted) strands of cotton. This technique makes wicks curl over as they burn, maintaining the height of the wick and therefore the flame. Because much of the excess wick is incinerated, these are referred to as “self-trimming” or “self-consuming” wicks.
In the mid-1850s, James Young succeeded in distilling paraffin wax from coal and oil shales at Bathgate in West Lothian and developed a commercially viable method of production. Paraffin could be used to make inexpensive candles of high quality. It was a bluish-white wax, burned cleanly, and left no unpleasant odor, unlike tallow candles. By the end of the 19th century, most candles being manufactured consisted of paraffin wax and stearic acid.
By the late 19th century, Price’s Candles, based in London, was the largest candle manufacturer in the world. Founded by William Wilson in 1830, the company pioneered the implementation of the technique of steam distillation, and was thus able to manufacture candles from a wide range of raw materials, including skin fat, bone fat, fish oil and industrial greases.
Despite advances in candle making, the candle industry declined rapidly upon the introduction of superior methods of lighting, including kerosene and lamps and the 1879 invention of the incandescent light bulb. From this point on, candles came to be marketed as more of a decorative item.