The HOTBIN R&D (Tony!) has been working on pulling together a complete “super” list of things you can and can’t compost. This bought our attention to the topic of chewing gum – so for a bit of fun!
IS CHEWING GUM BIODEGRADABLE AND/OR COMPOSTABLE?
I could have guessed, but I did not really know what chewing gum was made off. So I googled the question and read a few sites. They all implied chewing gum was not biodegradable. I tried to trace references – umm not many of them! A few made an effort saying they had found that chewing gum was made from a synthetic plastic, so no it was not degradable. I went to wiki to see if I could find a list of ingredients (yes (see wiki ingredients list)) and then I looked up the chemicals and finally I found some academic papers that actually have measured biodegradation of these chemicals.
I did not do this because chewing gum composting is important, or I have a lot of time on my hands – over the past few days I have looked up several items to cross check and find facts – It is getting very scary just how much information on the web is scientifically inaccurate and wrong.)
So here’s the thing: drum roll…
Revelation: chewing gum is a) biodegradable and b) compostable
A little bit of history and chemistry for those that enjoy a good story…
Chewing gums used to be made from natural plant gums (nature’s polymers – or if we must, nature’s plastics). All chewing gums made from natural gums were 100% biodegradable and compostable.
When consumers needed gum to last longer; to give the gum more bite (terrible pun!) and make more of it, manufacturers decided to added natural rubber (latex, another plant polymer) to solve the issue. Natural latex rubber is also biodegradable.
You may remember the rubber plantations started to run short of latex rubber around the time cars took off and we needed more tyres (tyres were made from latex rubber which is vulcanised – a chemistry zap not a Star Trek one!). Next the GIs in the war started to run out of chewing gum, so told the generals to get the chemists to make a synthetic gum pronto to keep up morale. OK I made that up! Chemists copied latex because we needed more rubber to make more things like tyres. This synthetic (man-made) latex rubber (I won’t add the chemical formula) plus a bunch of other “stuff” also found its way into today’s chewing gum.
The thing about natural latex rubber and manmade rubber is they are the same chemical polymer and both are biodegradable.
WHY DO MOST WEBSITES SAY IT IS NOT COMPOSTABLE OR BIODEGRADABLE?
Some of this is probably due to association – our pavements are full of chewing gum. Councils spend millions trying to get rid of it which infers a sticky problem that does not go away naturally – it needs effort. (Of course, I could also say lazy web ‘copy and paste’ with no reference to checking the facts also does not help).
What the pavements really infer is chewing gum is thrown away faster than bacteria can consume it. As a HOTBIN customer and blog reader, you will know the speed of all biodegradation depends on conditions – oxygen, temperature, water, ph etc. A pavement is not a good composting environment and it certainly is not a hot composting environment.
CHECK IT OUT FOR YOURSELF!
We would like to invite HOTBIN composters to prove chewing gum is compostable. Take a full packet of gum (ie known weight), unwrap and place the bits in a pair of old tights (tights will not decompose quickly and we should be able to locate any gum left). Place it in HOTBIN and leave. After three months take it out, wash off compost and weigh. Based on the science evidence (anyone wanting the academic paper email me) it should hot compost and fully decompose (disappear) in around 3 months. (R&D HQ – aka Tony’s back yard will start the test tomorrow or as soon a trip to the garage to get a packet has been made!)
Composting gum is NOT the answer to littered pavements – changing human behaviour is.
It should be socially unacceptable to drop chewing gum (or any litter for that matter!). In 2000, a study on Oxford Street(London) showed that a quarter of a million blobs of chewing gum were stuck to its pavement. (YUCK!)
Live and let live or if you do want to be mischievous and try put someone off chewing gum, how about sharing these two quirky facts!
- Did you know chewing gum in one step away from chewing a car tyre?
- Did you know that gum in your mouth is the same as chewing a condom!
If you do try our little composting experiment with chewing gum please do let us know your findings!