As Green as it Gets:
Potato Starch Set to Challenge Bioplastic

Earthpac II

It’s that special time of the morning. When the sun is still rising, the earth still damp from dawn’s dew, and no sound disturbs the chorus of morning birds. Even under this light, in this pure state, uprooted from an early-morning harvest and sitting in a basket on the farmhouse table in front of you, there’s nothing very sexy about a potato. So what can possibly be sexy and exciting about a tub of starchy water sitting in a sterile factory, a byproduct of the robotic process of manufacturing millions of potato chips for supermarket shelves?

Quite a lot, actually.

At a big festival last year, I was pleased to discover that the plastic fork and plate I had just used could be put in the green compost bin. Not the waste one. Not the recycling one. The green-lidded compost bin. Or so I thought.

Earthpac I

I’ve since learned that most plant-based bioplastics still have to be taken to an industrial composting centre and broken down in temperatures above 60 degrees celsius in order to decompose. Also, a lot of the major companies involved in developing bioplastics are so big that large-scale demand may lead to less-than-ideal effects. Like deforesting large swathes of Brazilian forest to plant more sugarcane. Or pumping chemical fertilisers into soils to produce enough corn to make polylactic acid (PLA) products. Still, I guess this is ‘making progress’?

But imagine a world in which you could simply eat the package instead of having to throw it away in the first place. What a world that would be!

That festival, and the subsequent discovery that bioplastics have a few drawbacks, got me wondering whether potato-starch plates are as wonderfully green and sustainable as they seem. If so, why do you never see those at major festivals? I quickly discovered one reason why: people from outside New Zealand seem to have no idea what I’m talking about.

Since the early 2000s, New Zealand company Earthpac has been manufacturing plates made of potato starch, a leftover waste product from potato chip factories. In a process that sounds like a psycho souped-up version of the scary part at the end of Toy Story 3 when they’re on the conveyor belt, potatoes are water-blasted, at 120 kmph, through blades that slice them into whichever shape they should be. From contact with so much sliced potato surface area, this water is laden with sticky icky starch (which, if simply disposed of down the drain, can suffocate soils or solidify in riverbeds and cause environmental problems).

Earthpac III

Instead of being thrown away, the starch is extracted and the clean water can be reused in the factory. That extracted starch is bought by Earthpac and, using machines designed, built and maintained by the company’s founder – former aviation engineer Richard Williams – the dried potato starch powder is compressed, heated and set in rigid shapes to make small trays, boxes and plates that for the past decade have been a favourite of farmers markets and eco-friendly barbecues around New Zealand.

The potato starch products break down within a month in your compost heap or worm farm, so there’s no need to find an industrial composting plant. There’s nothing toxic or harmful at any point in the process. You can even eat the plates, if you want to. Just remember, ‘edible’ doesn’t mean tasty.

There’s also very little waste to worry about: the plates are made from a waste product that was going to be thrown away in the first place anyway. Any misshapen plates or organic factory waste are given by Earthpac to a local farmer, who feeds them to his pigs.


It’s a happy harmony of science, nature, engineering, food, waste reduction and sustainability. Though of course there are still a few issues: the problem of the potato plates not being waterproof or heatproof (since the starch molecules would break down too quickly) is one that has always limited the growth of potato-starch products on the market. However, after almost a decade of research and development, Earthpac may be close to producing a biodegradable coating that will be able to withstand heat and hold liquids.

A world where we don’t walk past trash cans overflowing with takeaway coffee cups may be closer than we think – that is, as long as we keep up our addiction to potato chips. But I don’t see that being the problem.

pictures: stills from mediamash


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