Materials

Should you put tea bags in your food waste bin?

The phenomenon of Blue Planet II has shined a spotlight on single-use plastic and the damaging effect it has on marine life and the environment, prompting us to re-examine the plastic found in everyday products, from take-away coffee cups to cotton buds.

But what about the items we don’t think of as plastic? It’s quite common to see tea bags put into a household food waste caddy – after all, they’re just tea leaves and a compostable papery bit, right?

Not quite. Most bags, including those made by the five leading tea brands in the UK – PG Tips, Tetley, Twinings, Typhoo, and Yorkshire Tea – use non-biodegradable polypropylene as sealants in their bags. A spokesperson from the makers of Yorkshire Tea confirmed to Resource: “Our tea bag material contains around 25 per cent polypropylene (PP) which we believe is typical for the market. It’s a component of the material that allows us to heat seal the bag.”

The tea's been made, so what should you do with the bag?
But even though manufacturers acknowledge the use of non-biodegradable plastic, the advice to tea drinkers is still to put their bags in compost or food waste caddie.

A spokesperson from Unilever, the makers of leading brand PG Tips, says: “Our PG tips pyramid bags are mostly made of paper with a small amount of plastic which is used to seal the tea bag. These tea bags are suitable for composting and can either be recycled in home compost bins or added to food waste collections.”

The official guidance from WRAP is also to compost your bags. The organisation’s Recycle Now website says that when you come to use the compost there is a ‘thin skeleton’ of the bag still visible after the leaves and paper components have broken down. It recommends that ‘these can be sieved out and discarded or dug in with the compost’.

The skeleton left behind however is the non-biodegradable PP and therefore not 100 per cent compostable. Assuming you don’t put it in general waste, do you let the skeleton contaminate your compost, where you might grow vegetables, or put it into a food waste bin where it will undergo commercial composting or anaerobic digestion (AD)? And does it then affect the quality of the compost created through this large-scale recycling?

The tea bag making process applies the PP as fibres which melt creating the seals which stop the bag falling apart,” explained Charlie Trousdell, Chair of the Organics Recycling Group. “Since they are fibres – we are talking a few microns thick here – they will not lead to a PAS [a quality standard for compost and digestate] failure or even be that visible during inspection so it is hard to know their fate in the soil.”

With 165 million of these being used every day, and therefore entering the waste stream every day, there is understandably some cause for concern about the cumulative effects of microplastic. Researchers at Heriot Watt University in Edinburgh have begun to study the effects of contaminate microplastics in the digestate left over after food waste AD.

Should you put tea bags in your food waste bin?
Many tea bags contain a plastic skeleton that won't biodegrade
The team found a variety of plastics in the three Scottish AD sites tested over one day, but the amounts discovered are no cause for alarm, yet. Further research is needed to understand the effect of plastic on soils, which is lagging behind the well-documented effects on our oceans, according to the researchers who reported their findings to the Scottish Environment Protection Agency. But if microplastics can end up in plankton and fish, there’s no reason why the food we grow and eat will also end up being contaminated.

There are therefore two simple ways to avoid this: no bag at all – the traditional teapot and strainer method, which comes in all manner of different infusers and inbuilt strainers, making it a more convenient option when throwing away pesky leaves – or 100 per cent compostable bags. These are available from smaller manufacturers, and some lesser-known brands from the big five manufacturers, such as PG Tips Pure Leaf. Co-Op Food has also recently announced plans to do away with the plastic fraction of its own-brand tea bags.

PLA (polylactic acid) bags are made from organic sources and therefore 100 per cent compostable. Premium ranges of tea bags offer fully compostable bags, with brands such as Teapigs making their ‘teatemples’ from corn starch. These take longer to break down in a regular garden compost heap, according to Trousdell, who recommends putting them in a food waste bin. “Obviously the best solution is not to use tea bags at all and use loose leaf tea. The tea tastes much better!”

That’s just one more reason to go bagless, and you will have the blessings of George Orwell – that other authority on tea-making – who instructed in his 1946 essay A Nice Cup of Tea: “The tea should be put straight into the pot. No strainers, muslin bags or other devices to imprison the tea.” 

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