We're replacing the oil-based plastic in our tea bags with a plant-based plastic called PLA - and the switch is going pretty well so far!

Some of them are in the shops now - and by the end of April, we reckon we'll have made about 360 million tea bags with the new material.

If all goes well, about 20% of the UK Yorkshire Tea bags we make from that point will be PLA. That should be up to 50% by the end of June, and by January 2021 all UK Yorkshire Tea, Yorkshire Gold, Yorkshire Tea Decaf and Yorkshire Tea for Hard Water will have switched.

We're strength-testing the heck out of them to make sure they're tough enough - but it's still early days, so if anything goes wrong with yours, please let us know here and we'll sort it right away.

"Plastic free"

PLA tea bags are sometimes called "plastic free”, but we've never used that label and WRAP, the people behind the UK Plastics Pact, also advise against it because plant-based plastics are still plastics.

Why change from one plastic to another? Well unlike traditional plastics, which are made from fossil fuels, plant-based plastics are made from renewable biological sources (like corn starch).

It's also better when it’s thrown away, as long as it goes in the right bin. PLA tea bags are industrially compostable, which means they can go in food waste or garden waste bins for the council to compost.

As it's so important to dispose of them like this to get the biggest environmental benefit, we want to be completely accurate when we talk about them. So we're following WRAP's advice and avoiding the phrase "plastic free".

Our bumpy journey

In late 2018 we tested PLA on Yorkshire Gold. We thought we'd got the hang of it and started rolling it out more widely - and then we had a bit of a disaster. The sealing on some bags wasn't working properly and they fell apart in people's mugs. PLA, it turns out, is a lot trickier to work with than oil-based plastic.

So we rolled back and went back to testing and trialling. We've tried a ton of stuff, including refurbishing our machines and tweaking all sorts of settings - and everything made a difference, but nothing fixed the problem completely.

Then we called in Sheffield University. Last summer, they helped us study the tea bag paper – and we used what we’ve learned to work with the supplier to redevelop it.

We've now gone through our first trials and have started the rollout across the whole factory. If all goes well - fingers crossed - we'll be able to hit our target.

It's uncharted territory and there have been some pretty big bumps in the road already, so we have to be upfront about it being an aim, not a promise. What we do promise, though, is to try our best - and to keep being honest and transparent with you.