Don’t we all love burning candles! Candles hold many different meanings and functions: ceremonial, ritualistic, symbolic or plain utilitarian - as they have for thousands of years. Maybe it’s as well to know what we are burning and more to the point, inhaling. Candle ingredients don’t just disappear when they burn. The interaction of wax, aromatic oils and wick with fire produces carbon dioxide, steam, light, heat and the release of chemical vapours and soot into the environment. Having said that, we can never live in a chemical-free environment. Every substance on this planet, organic, inorganic or man-made, contains and emits chemicals and radiation, including our own bodies. That doesn’t necessarily mean all synthetic chemicals are bad - or that every “natural” chemical is automatically safe. Every substance has the potential to be toxic if used incorrectly. Unfortunately, candle-making is a largely unregulated industry and there isn’t much conclusive research regarding toxicity of emissions and little guidance in labelling (apart from fire safely warnings). A candle may contain 1% soy and still be labelled as a ‘soy candle’. A paraffin wax may be labelled ‘pure’ but what does that actually mean?
Paraffin wax
By far the most popular candle material. Paraffin wax is a colourless, hard wax of straight-chain hydrocarbons ranging in melting point from about 48°C to 66°C. The basis for paraffin wax is slack wax, which is a mixture of sludge oil and wax. Once petroleum has been extracted from crude oil, the slack wax is heated, mixed with strong solvents and then chilled and filtered. The oil journeys on to be processed into lubricating oil; the wax, on to further refinement for different markets. Candle wax is further chemically treated to bleach unacceptable colours and to remove odours. Synthetic paraffin wax was introduced commercially after WWII. Snow-white and harder than petroleum paraffin wax, synthetic wax is a hydrocarbon wax obtained by the controlled polymerisation of ethylene.
Plant waxes
Soy wax is made from soybeans. The beans are harvested, cleaned, cracked, hulled, and rolled into flakes, then mechanically pressed to extract soybean oil. The raw soybean oil is filtered and then hydrogenated with a catalyst such as nickel (the nickel promotes the reaction but doesn’t exist in the final product). This process creates a creamy wax. Little waste is produced from the processing; the remaining solids can be used as livestock feed. Soy wax, for example, is best for scented candles as it ‘throws the scent’ more than other types of wax, however it has a very low melting point, so it tends to drip if not used in a jar or container. Soy wax is not the only wax made in this way; a much similar process is used for Coconut wax, Palm wax and Rapeseed wax. These waxes are all-natural products typically with no harsh chemicals or additives. Coconut wax is usually blended with soy or rapeseed oil to get a ‘candle’ quality. It is more expensive and sustainable practices vary. Palm oil wax comes with a lot of negatives. A short, easy to harvest, native species of West and Central Africa palm is extensively farmed in Malaysia, Indonesia and Africa. It is the highest yielding of all oil crops. While it is a renewable resource, some countries are allowing this resource to decimate natural environments due to their poor economic conditions and lack of environmental regulations. The US Associated Press has also reported conditions akin to slavery in the production of palm oil.
Beeswax
Estimations show that young worker bees consume eight grams of honey to produce just one gram of wax. They have special wax-producing glands in their abdomen. The wax is extruded through small pores and it develops as small waxflakes on their abdomens. Other worker bees collect these wax flakes and start their chores with chewing, then building and repairing combs to store nectar, honey and the eggs and pupae nursery. Commercial beeswax is obtained by melting a honeycomb with boiling water and then straining and cooling it. Farmed honeybees are vulnerable to mishandling, mistreatment (queen bee wings are cut off or clipped so she can’t leave the hive), and mass-transported to where flowers are blossoming. Native bees are becoming one of the most endangered species on the planet and farmed bees can be subject to unnatural living conditions, genetic mutation, and stressful transportation. (Choose your honey producer carefully). Synthetic beeswax is engineered in labs to match the appearance and properties of natural beeswax. It’s created with a blend of fatty esters, fatty acids, fatty alcohols, and hydrocarbons. It’s generally safe to use but contains ingredients similar to synthetic paraffin wax.
Candle Wax Additives
Candle Wax Additives Additional chemicals are added to candle wax to increase melting point and burning life. Candle makers then add further chemicals for aroma, colour and texture. However, in spite of the large market penetration of scented candles, very few works have investigated their polluting emissions. 2011 Italian research investigated Volatile Organic Compound (VOC) emissions from the burning of scented paraffin candles in a laboratory-scale test chamber”. The researcher found that the emission amounts of BTEX (benzene, toluene, ethyl benzene and xylenes) and PAHs (contaminants which occur naturally in coal, oil and petroleum) showed large differences among different brands of candles. Aldehyde emissions were consistently related to additives. Aldehydes = oxidation of alcohols - typically formaldehyde and acetaldehyde in synthetic additives. Most candle colourants and fragrances have some, if not all, synthetic ingredients. They will emit somewhere between negligible to nasty levels of VOCs. There are hundreds of VOCs - they are common indoor air pollutants discharged by a wide variety of household products and building materials not just candles. According to an earlier German 2007 study, “Combustion products were virtually identical in composition and quantity” between paraffin, soy, palm, beeswax and stearin candles and posed no health hazard if burned according to several international health standards. However, it is important to note this research was funded and published by a conglomerate of industry petrochemical refiners and candle manufacturers! Fine wire (such as copper) can be included in the wick. This provides two advantages: it makes the wick more rigid, letting it stand further out of the liquid wax, and it conducts heat downward, melting the wax more readily - which is particularly important in candles made of harder wax. Stiffeners were once made of lead but these have been banned for sale in Australia since 2010. Other core stiffeners, such as paper and synthetic fibres, may also be used. Virtually all wicks are treated with various flame-resistant solutions in a process known as mordanting. Common treatments are pre-soaking in borax and/or salt. It is important that the wick not glow after the flame is extinguished. Typical agents used are ammonium nitrate and ammonium sulphate. The wick composition also influences how the candle burns. Important characteristics of the wick are type of fabric, diameter, stiffness, fire-resistance, and tethering (to stop the wick floating). Candle wicks are normally made out of braided cotton. They are sometimes braided flat, so that as they burn, they also curl back into the flame, thus making them self-consuming. Large diameter wicks result in a larger flame, a larger pool of melted wax, and the candle burning faster. An experienced candle-maker will know how to match the wick type and size, wax type, fragrance, and candle size to produce a great burning candle. This is where we need faith in our chosen candlemakers that they are knowledgeable, reliable and ethical. However, a well-made candle is only one part of minimising emissions. The consumer has most the influence on success.
A Sooty Candle
The Sooty Candle The Ökometric Study showed evidence, comparing paraffin and soy candles, that sooty candles pollute the air to a much higher degree than clean burners, regardless of type of wax. The balance between wax and wick is crucial in minimising soot pollution. Wicking is when liquid wax fuel is drawn up through the wick by capillary action to the flame. Once the flame of the candle has started drawing the liquid candle wax up the wick, it does so at a steady rate. When the flame is disturbed, the size of the flame changes and the amount of fuel being used is no longer consistent. If there is excess fuel, it is emitted in the form of partially burnt waxy soot. If there is too little, the flame incinerates the wick, producing larger, drier, partially-burnt wick-soot particles. How much of a good thing is too much? How long should your candle burn before it becomes toxic to you, your children, your pets, your plants? If you burn your candle for more than 4 hours at a time, carbon will collect on the wick, and your wick will begin to "mushroom." This can cause the wick to become unstable, the flame to get too large. Apart from sooting it can be a fire hazard. The Australian National Occupational Health and Safety Commission (Now Safework Australia) recommends a workplace exposure limit of burning 2 mg of paraffin per cubic metre, over an eight-hour period in a confined room. By example, if your room is 30 cubic metres (3m x 4 m x 2.5 m high), you should burn only 60mg (30x2) over 8 hours in this air space, to be safe. An 8-hour paraffin candle weighs approximately 20,000gm. You should burn only 1/6 of it in 4 hours. This information is according to almost all international standards on paraffin fumes. If the room is well-ventilated, I guess that’s different, but beware drafts and floaty curtains and trim that wick. 1.Santino Recchia. Polycyclic aromatic hydrocarbons (PAHs) in indoor emission from decorative candles Atmospheric Environment. Volume 45, Issue 10, March 2011, Pages 1888-1895 2.Ökometric Wax and Emissions Study Bayreuth Institute Environmental Research 2007 Germany
Candle Care
Tips for efficient and safer candle burning (from around the Internet)
Place on a stable, fire-resistant surface free from vibrations
Keep away from children and pets and flammable materials
A burning candle should never be left unattended
Regularly trim the wick. Trim the wick to ¼ inch. You can use scissors, nail clippers or a wick trimmer, Untrimmed wicks are likely to take on an unhelpful shape that dulls the flame. Long wicks cause more soot. Remove trimmings and other foreign matter from the candle surface.
Once your candle's lit, allow the top layer of wax to melt most of, or all, the way across. This might take some time. Beware wide candles with one thin wick – not enough heat will be generated to melt all the way across. Failed full melt causes tunnelling. The wick starts to sink lower and lower (tunnels right through the centre of the candle). Eventually, the tunnel will be so deep that it'll be tough to light the wick at all. More importantly, all that unmelted wax (the memory ring) is hours of loveliness missed out on. That said, in some instances this can create a beautiful and ambient effect.
Keep your burning candle away from open windows, fans, air conditioners and heavily trafficked areas. Candles in containers have the benefit of a protected flame, but fire needs oxygen to burn. When you have a candle down inside of a container, the oxygen is quickly used up and more is needed for the flame to continue burning. More air is sucked into the container through the top but at the same time warm air is trying to get out. This turbulence causes the flame to dance and produce more soot the further down into the glass they burn. It also aids tunnelling. A candle capper will separate the two air flows and stabilise the flame.
When you blow out a candle, it smokes because the core of the wick continues to burn a little. The core of the wick can turn to carbon ash, making it brittle and the candle hard to light the next time. You could accidentally blow some of the melted wax right off of the candle. Extinguish the flame with a candle snuffer. Alternately, if in a container, cover the top and once the flame has used the remaining oxygen it will extinguish. Wick dippers are long-handled hooks used to submerge the wick in melted wax, then hook back into position for a quick clean flame next time.
Keep candles in an airtight container to maintain fragrance and performance. Highly fragrant candles have a life span of 6 to 12 months, depending on the scent. Use, enjoy, replace often.
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