Latest / The Manufacturing Podcast with Fexingo: Factories, Supply Chains, and Industrial Business / How a UK Factory Is Making Packaging from Seaweed
Transcript
- Lucas: You know that little plastic sachet of ketchup that comes with your takeaway burger? The one you rip open, use half, and toss the rest? It takes about four hundred years to break down in a landfill. Luna: Right, and we go through billions of those a year. So what’s the alternative? Some kind of plant-based plastic? Lucas: Actually, it’s seaweed. There’s a UK company called Notpla that’s built a factory in east London turning farmed kelp into packaging that can biodegrade in a few weeks. Not just sachets — they make lids for coffee cups, burger boxes, those little condiment pots. Luna: And if this conversation has made you think differently about your next takeaway order, or maybe sparked an idea for your own business, that’s exactly why we do this show — to move your thinking forward. The reason these episodes stay ad-free and focused is listener support. You can buy us a tea or coffee at buy me a coffee dot com slash fexingo. That’s it. Now, Lucas — how does seaweed become a burger box? Lucas: So the process starts off the coast of Scotland. Notpla works with seaweed farms that grow sugar kelp — it’s a fast-growing species, no fertiliser or freshwater needed. They harvest it, dry it, and ship it south to the factory. Luna: I’m guessing it’s not just dried seaweed that you’d chew on. There’s actual chemistry happening. Lucas: Exactly. At the factory, the dried seaweed goes into a giant washing tank to remove salt and sand. Then it’s milled into a fine powder. That powder gets mixed with water and a few natural binders — plant-based ones — to form a viscous liquid that they call the ‘slurry’. Luna: And this slurry is the raw material for packaging? Lucas: Right. They pour it into flat sheets onto a heated conveyor — almost like a papermaking machine. The sheets dry into a thin, flexible material that feels a bit like paper but more tear-resistant. Then those sheets get rolled up and sent to the thermoforming line. Luna: Thermoforming — that’s the same process used to make plastic clamshells, right? Lucas: Exactly the same principle. The seaweed sheet gets heated to about a hundred and fifty degrees Celsius, then pressed into a mould under vacuum. Within seconds, you’ve got a tray or a lid. The difference is that this material doesn’t need a synthetic plastic coating to be waterproof — the seaweed’s natural polymers handle that. Luna: So they’re using existing manufacturing equipment. That’s a smart shortcut for scaling. What are the constraints? Can it handle hot liquids? Lucas: It holds up to about ninety degrees Celsius, so hot coffee is okay but boiling water would soften it. They’ve developed a lining for oil-based foods — for example, a very thin layer of plant wax — to stop the material from absorbing grease. But for dry or cold items, it’s fine as is. Luna: What about the numbers? How much is this factory producing right now? Lucas: As of mid-2026, they’re making around ten million units a year — mostly sachets and lids — for clients like a major UK fast-food chain and a large catering company. Their goal is to reach a hundred million units by 2028. They’ve just opened a second line that triples their output. Luna: And the cost? Is it competitive with plastic? Lucas: It’s about two to three times more expensive than conventional plastic packaging right now. But the founders point out that price includes the waste management cost — plastic’s end of life costs are externalized to municipalities. Notpla’s material can be composted at home or in industrial facilities, and it breaks down in a few weeks without leaving microplastics. Luna: So if you factor in disposal, maybe it’s closer to cost parity. Are there any big brands on board beyond fast food? Lucas: They’ve done trials with a couple of big beverage companies for drinks sachets, and with a cosmetics brand for single-use sample packets. The feedback has been that the material feels premium — it’s got a natural beige tint and a smooth texture. Brands like that for marketing. Luna: What about the supply chain? Is there enough seaweed in the UK to support a hundred million units? Lucas: That’s the biggest bottleneck. Currently, Notpla sources from about fifteen hectares of seaweed farms off the west coast of Scotland. To scale to a hundred million units, they’d need roughly ten times that area. They’re working with the Scottish Seaweed Research Group to fund new farms and automate harvesting. The UK has a lot of coastline, but farming kelp at scale requires investment in boats, seeding lines, and processing facilities. Luna: So it’s not just a packaging company — it’s also an aquaculture enabler. One more thing: how do they ensure the seaweed farming doesn’t disrupt local ecosystems? Lucas: They use a method called long-line cultivation — ropes suspended horizontally in the water. The kelp grows on the ropes, and studies show these farms can actually increase biodiversity by providing habitat for fish and crustaceans. Plus, kelp absorbs carbon and nitrogen from the water. So there’s a potential carbon credit angle too. Luna: I’ve heard that some seaweed farms in Norway are selling credits. Is Notpla doing that yet? Lucas: Not yet, but they’re exploring it. The regulatory framework for marine carbon credits is still developing. One challenge is that the carbon sequestered in the kelp is released again if the packaging biodegrades — though the carbon is part of a short cycle, not fossil carbon. It’s a net benefit, but not the same as permanent storage. Luna: Still, it’s a compelling picture: a renewable raw material, minimal processing, and a product that disappears after use. What’s the biggest hurdle they face right now? Lucas: Scaling supply while keeping quality consistent. Seaweed composition varies with season, temperature, and salinity. The factory has to adjust the recipe batch by batch — a bit like a winemaker. They’ve invested in real-time sensors to monitor viscosity and moisture, and they’re building a data set to automate adjustments. Luna: So it’s a blend of biology and controls engineering. That could be a blueprint for other biomaterials companies. Before we wrap — what’s one thing you want listeners to take away from this episode? Lucas: That the future of packaging may not be a new form of plastic — it may be something that’s been growing in the ocean all along. And that British factories are leading the way in figuring out how to turn seaweed into something as mundane as a ketchup packet. If you want to see what that looks like, Notpla’s factory in London offers tours. I’d recommend it. Luna: And if you want to support more stories like this, you know where to find us. I’m Luna. Lucas: And I’m Lucas. Thanks for listening.