What's the Difference Between Biodegradable and Compostable?

David Platt • 26 July 2019

Both are great forms of environmental practice, but what's the difference?

We recently came across a statement by a plastics manufacturer which said they had produced a biodegradable polythene bag through the use of additives in the manufacturing process. A little scientific understanding would suggest this could be a misleading statement aimed at capturing the upswing in interest in environmentally friendly materials. This begs the question, what is the main difference between biodegrable materials and compostable materials?

Biodegradable Materials

Biodegradable materials will break down to water, carbon dioxide and other naturally occurring materials. There is no formal time limit on this definition but an expectation that this will occur within a 12 month timescale. The problem, of course, is that the bacterial action required depends on the amount of oxygen present. The temperature and oxygen conditions of a landfill can vary enormously.

By putting additives in to some plastics they can become what may be called oxo-degradable. If the plastic is left out in the open air then the sheet of plastic will degrade and fall apart. However, at a chemical level, the long chain polymer molecules that make up the plastic remain intact.

Compostable Materials

"Compostable" refers to biodegradable materials which break down to ‘useful’ nutrients components. There are two strict British Standards definitions of what is Industrial Composting and Home Composting . These define the temperature and atmospheric conditions and the amount of material left after a period of time.

The systems also provide recognisable logos for manufactures to put on their products.

	Industrial Composting: BS EN 13432	Home Composting: Vinçotte Certification Programme
Biodegradation	Test performed at 58 °C +/- 2 °C, carbon dioxide at least 90 % compared with control within 6 months (approx 182 days)	Test performed at ambient temperature (20 - 30 °C), carbon dioxide at least 90 % compared with control within 365 days
Disintegration	Test performed at whatever temperatures are achieved in vessels, each at least 140 litre capacity. At maximum of 12 weeks (approx 84 days) no more than 10 % of original dry weight of test material > 2 mm.	Test performed at 20 - 30°C in vessels each at least 140 litre capacity. At maximum of 26 weeks (182 days) no more than 10 % of original dry weight of test material > 2 mm.
Current certification and logos	AFOR / Din Certco	Vinçotte

Source: https://www.bpf.co.uk/topics/standards_for_compostability.aspx

Final Words

So, the plastic bag with an additive is oxo-biodegradable and not really biodegradable. The ‘plastic’ bag made from corn starch is fully home compostable and truly biodegradable.

Only one word of caution, is that the corn starch ‘plastic’ should not be added to the plastic recycling because it contaminates the plastic recycling process and has to be removed before the product is extruded.

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Evaluating Carbon Footprint in Branded Merchandise

by David Platt • 13 April 2026

SUMMARY: Comparing eco promotional products is difficult because of the range of materials used Carbon footprint is a measure which allows comparison Need to look at CO2 equivalent because of the use of organic solvents in promotional merchandise There is a difference between Cradle to Gate and Cradle to Grave in the measurement, because we never know whether the end user will attempt to recycle products Pavilion is a specialist in providing branded promotional products, which are sustainable. The most common question we're asked, of course, is what's the most sustainable branded product? And how would you measure that? And that's a difficult question and often comes with hesitations. Why? This blog aims to try and explain eco credentials, particularly for promotional merchandise and how you might compare them. The first problem you have, is that you're comparing different materials. This is why it's difficult is because there's no true standard of sustainability. There is no international marking that says, this one's a 10, and this one's a 1. The nearest you have is carbon footprint. Carbon footprint generally means the amount of carbon dioxide measured in kilos, but you have to be a bit careful with that, particularly for promotional merchandise because carbon dioxide is not the only greenhouse gas. You may be fully aware that methane, natural gas has a global warming effect 50 to 60 times more than CO2. So, you don't need to measure just CO2, you've really have to look at a CO2 equivalent. In other words, converting the methane. And why do I mention that? Promotional merchandise is often printed and unless you are using water based inks, there will be solvents, and therefore, CO2 equivalent is what you need to measure. The next problem that you've have is what are you measuring the carbon footprint of? Are we talking what's termed - Cradle to Grave or Cradle to Gate? The concept is explained in the diagram.

Cork for Eco Branded Merchandise

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