Is candle wax biodegradable? Can it be composted?

  • Date: August 4, 2022

From helping to create a cozy ambience to providing the finishing touch to a birthday cake, candles are a common feature in most households across the country. Being difficult to recycle, they provide a bit of headache when it comes to disposal. Are they simply destined for the trash and, ultimately, landfill? Or is candle wax biodegradable and can it be added to the compost bin? Well, it largely depends on what it is made from. Here we look at some of the things you need to consider before throwing them in there.

Firstly, what are candles made of?

If we know what an item is made from it can help us determine if it is biodegradable (and compostable) or not. In their simplest form, candles contain wax and a wick. The wick, generally, consists of braided cotton or even wood but the wax is a bit more variable in terms of its ingredients!

The most common type of wax used in candles is paraffin. This is derived from petroleum and although it comes from a natural source it is not, generally, classed as a natural wax. Natural waxes – such as soy wax, coconut wax and beeswax – are being increasingly used in candle production. This upturn in natural wax use is, at least partly, due to the environmental impact of the fossil fuel industry (of which paraffin wax is a by-product).

So, is candle wax biodegradable?

If an item can be broken down into its component parts by micro-organisms such as bacteria, it is said to be biodegradable. Some candle waxes biodegrade, whilst others don’t.  Generally, candle wax that comes from natural sources – such as beeswax or soy wax, will biodegrade whilst candles made from man-made wax, such as paraffin, will not biodegrade. They will break down over time into smaller pieces, but this is not the same process as biodegradation.

You should be aware that suitable conditions are required for a material to biodegrade. Often people assume that item will biodegrade in landfill in the quoted biodegradation timeframe. This is, generally, not the case. In landfill space is limited and items crammed in. The lack of airflow and moisture can really hinder the process. Many people opt for biodegradable items which end up in landfill for many years longer than they expect. We always advise reusing items and diverting them from landfill for as long as possible – even biodegradable ones.   

Is candle wax compostable?

Composting can help us reduce the waste that we send to landfill whilst providing some nutritious fertilizer to use in the garden. It is a common misconception that if an item is biodegradable, it can be composted. However, the words ‘biodegradable’ and ‘compostable’ do not mean the same thing – there are subtle differences. For instance, if an item is biodegradable but contains harsh chemicals it may not be suitable for composting – the chemicals could contaminate the pile.

Composting materials fall into two categories. ‘Green’ materials refer to items that are rich in nitrogen such as freshly cut grass or urine (yes, urine). ‘Browns’ are rich in carbon and include items such as wood.  Natural candle wax falls into the carbon-rich ’browns’ category. It is important to ensure you have suitable mix of both ‘browns’ and ‘greens’ in the mix. Too much carbon-rich material can mean a dry pile, too many ‘greens’ can result in a slimy, smelly mess! Some trial-and-error is required, but you won’t go far wrong with a 1:1 ratio. Monitor it and adjust as you go. 

As far as composting goes, waxes are quite straight forward. They should only take a matter of weeks – or months. If you are new to the composting world, we have answered some of the commonly asked newbie questions here.

Some considerations when composting candle wax…

Candle wax is often made up of more than just wax. Chemicals are often added to make the candles smell nice and to add color. This must be considered when adding candle wax to your compost pile. We advise you to look at the ingredients list of the candle and take it from there. As with any composting, erring on the side of caution is always a better idea than risking contamination.

Although it isn’t a lengthy process to compost natural candle wax, it can still be sped up. Breaking the wax into smaller pieces will make the process that little bit quicker. This simply allows the bacteria to have a larger surface area to do their thing. The smaller pieces can also be distributed throughout the pile, spreading their carbon as they go.  

The bottom line

Composting is a great way to reduce what we send to landfill – it is especially great for non-recyclable items. Candles are not made equal – they are made from a variety of different waxes. In general, the natural waxes are biodegradable whilst paraffin wax (unfortunately the most commonly used candle wax…) is not. If you can’t reuse, gift or repurpose your candle, natural waxes can add a useful carbon-rich ‘brown to the mix and will contribute to a nutrient-rich fertilizer. Just be sure to check the ingredients list for any nasty chemicals.