Degradable vs. Biodegradable vs. Compostable – What’s the Difference?

Are you trying to make more eco-friendly choices when you buy, but so confused by all the terminology that is thrown about to try to convince you something is ‘green’? You are not alone – even the people using these terms often don’t really understand what they mean.

We’re here to help! We hope that by sharing an understanding of what these things mean, we’ll be able to inspire people in every home and organisation to make sustainable and eco-friendly product choices without the confusion!

Degradable

is a broad term given to natural and man-made substances that can be broken down by natural processes into smaller parts. Basically everything is degradable!

Things can be photodegradable (broken down by ultraviolet light), oxodegradable (broken down by thermal exposure) or biodegradable (broken down by the action of microorganisms).

The term ‘degradable’ in itself does not specify any time frame in which something will break down…for instance, old paintings are displayed under dim lighting to reduce the effects of photo-degradation, which could take place over years. A large tree trunk might take a century to biodegrade. A tin can is degradable too; it will break down over a long period of time through oxidation, and weathering. An Oxo-degradable plastic bag (regular plastic that has been treated to make it degradable), will begin to degrade after about 12-18 months, and the time it takes will depend on how much light and stress (movement) it experiences. But it is still made from a non-renewable resource, and could stay in the environment for many years.

Biodegradable 

is a term given to material that, as a result the of biological activity of microorganisms (bacteria, fungi and algi), breaks down completely into the raw materials of nature (CO2 , H2O, inorganic compounds and biomass) from which it was made, and disappears into the environment. Just like the term ‘degradable’, biodegradable does not give any indication of time frame so the process could take years – for example, the straw in a straw-bale building will biodegrade over many years, if not maintained. The good thing is that if something is certified biodegradable, you know that the end result is going to be the raw materials of nature.

Compostable 

is a specific term given to biodegradable materials that biodegrade within in a certain time frame under typical composting conditions. To make things even more complex, it is important to differentiate between ‘home compostable’ and ‘commercially compostable’. 

What then, is the difference between ‘commercially compostable’ and ‘home compostable’? Quite a bit. 

If a product is ‘certified commercially compostable’, it might be certified to US & European standards, and/or to Australian Standard (AS4736),which goes one step further and has a worm toxicity test. To be certified as commercially compostable, the product has been proven to break down completely in the space of one commercial composting cycle. Commercial composting cycles incorporate more heat and movement that the usual standard home compost bin – so more can be composted commercially than in a home compost (for example, PLA bioplastics which require a high temperature to start the breakdown process). Most of our Biopak range is certified commercially compostable to US, European and Australian standards.

If a product is certified home compostable, it can again be to US and European standards and/or to Australian standard (AS 5810-2010), which has the further step of testing for toxicity to worms and other micro organisms during the breaking down process. If a product is certified home compostable to Australian Standards, then you know it will break down in an ordinary home compost bin.  Our Biocane range of plates, bowls and trays, our napkins and straws are all certified home compostable to Australian Standards.

So which is best? Degradable, biodegradable or compostable?

We believe that if possible, ‘compostable’ is always the best option, because it ensures that a material will break down to the materials of nature, in a short time frame.

However, like all decisions, the deciding factors will be how you are using something, and how you plan to dispose of it. If you are organising a large event, you ideal scenario will be that you choose compostable catering ware and work with a commercial composter to compost all food scraps and catering ware. This is the way of the future, and we believe it will one day be how ALL events are run.

Even if you are unable to compost, compostable products are still an excellent choice because they will break down the fastest, and into the base materials of nature. Common ‘compostable’ items you can choose from are home compostable rubbish bags, Home compostable biocane plates, bowls and platters, and Commercially compostable Biocup coffee cups.

Our second choice would be biodegradable – because it turns back into natural materials eventually, even though it takes longer than a compostable product. Sometimes things might only take twice the time frame required to be certified commercially compostable, but if you are home composting and have time, this might still be a good option. An example would be our wooden cutlery, which is too dense to be broken down in one composting cycle, but which will definitely turn back into the materials of nature given just a bit more time. Common ‘biodegradable’ items are wooden cutlery.

Personally, we don’t like ‘degradable’ products. We think they are misleading and confuse people into thinking they are biodegradable and an eco-friendly choice (see the image of the degradable bag at the top of this blog). A degradable bag is simple an ordinary plastic bag made from a non-renewable resource (oil), which will only degrade into smaller pieces of plastic – what’s so eco-friendly about that??

We hope this article has helped you navigate some tricky green terminology – post a comment or write to us if you have further queries or ideas.