Seaweed

Join food journalist Lee Tran Lam to explore Australia’s foodways. Leading Australian food producers, creatives and innovators reveal the complex stories behind ingredients found in contemporary kitchens across Australia – Milk, Eel, Honey, Mushrooms, Wine and Seaweed.

When you skip by seaweed on the beach or crunch into nori wrapped sushi rolls, you're interacting with something that also exists as billion year old fossils. In lutruwita/Tasmania, palawa people have crafted bull kelp water carriers for millennia, and from Ireland to Japan, seaweed’s been a culinary ingredient, a cough remedy and a way to pay taxes. Nowadays, this versatile alga gets shaped into sushi rolls, musical instruments, plastic alternatives, and could be a powerful tool in combating climate change.

Lee Tran Lam Powerhouse acknowledges the Traditional Custodians of the ancestral homelands upon which our museums are situated. We pay respects to Elders, past and present, and recognise their continuous connection to Country. This episode was recorded on Gadigal, Kaurna, Peramangk and Bundjalung Country.

My name is Lee Tran Lam and you're listening to season two of the Culinary Archive Podcast, a series from Powerhouse Museum.

Located in Sydney, Powerhouse is the largest museum group in Australia. It sits at the intersection of the arts, design, science and technology, with over half a million objects in its collection including Japanese seaweed from 1879; kelp that was steam-dried a century ago; and a 1990s free sushi party flyer. The collection charts our evolving connection to food.

The museum's Culinary Archive is the first nationwide project to collect the vital histories of people in the food industry, such as chefs, producers, writers and restaurant owners who've helped shape Australia's taste and appetites. Today we're talking about Seaweed.

Dr Pia Winberg 30,000 year old relics exist of giant kelp water carriers from Tasmania. It has to be one of the first pieces of evidence of industrial use of seaweed.

Emiko Davies Kombu, it's like the backbone of all Japanese cuisine.

Sarah Thomas There's an amazing lady in Australia using seaweeds as a natural dye for textiles. People are using seaweed to create lingerie.

Emily Sheppard I hope that hearing the sound of the kelp helps us to remember — it's a completely different world when you put your head under the water.

LTL When you skip by seaweed on the beach or crunch into nori-wrapped sushi rolls, you're interacting with something that also exists as billion year old fossils. In Australia, palawa people have crafted water carriers from bull kelp for millennia, and from Ireland to Japan, seaweed hasn't just been a culinary ingredient for generations, it's also been a cough remedy and a way to pay taxes. Nowadays, this versatile algae gets shaped into musical instruments, plastic alternatives, and could be a powerful tool in combatting climate change.

ED Hi, my name is Emiko Davies. I'm an Australian Japanese cookbook author based in Italy. I've written six cookbooks, and my latest book is called Gohan: Everyday Japanese Cooking. I grew up in Canberra in the 1980s and I'm quite amazed at how my mother was able to continue cooking things that reminded her of home.

LTL Seaweed has seasoned dishes in Japanese temples for centuries. As a vegetarian-friendly flavour enhancer, it was embraced by Buddhist monks, who likely played a role in raising its culinary profile. In Japan, seaweed is in everything, from the materials to preserve paintings to the actual walls of Himeji Castle. Wrapped around today's sushi rolls are sheets of nori. Developed around 1750, the seaweed's crisp, page-like form was inspired by papermaking methods and it's an ingredient that Emiko has long savoured.

ED We always had seaweed on the table. I loved onigiri. It's like one of the most comforting foods for me. So onigiri are rice balls. You wrap nori around them, so that you can easily hold them and not get your fingers sticky.

LTL Thanks to a 2000 year old fossil, we know Japanese people have snacked on onigiri for millennia. It was exchanged as a gift amongst the nobility and it's fed everyone from the military to train commuters.

ED To make onigiri, start with a rough ball of rice. Then you cup your hands and sort of push the rice together so that it comes together in a triangle and it doesn't all fall apart. The act of sort of pushing it together is like you're transmitting your love into the ball of rice. The actual word ‘onigiri’ comes from two words: ‘o’ means giving honour, and ‘nigiri’ means to grasp. I just think it's more than a bowl of rice. It's something special. You can put anything in there or you can also just completely leave it plain and just eat it with a nori sheet around it. When my mum used to make it for me she would pack the nori separately so it wouldn't get soggy. Even the onigiri that you buy in the konbini, in the convenience stores, have got that really genius way of packaging so that the seaweed is separate from the rice. You just have to follow the instructions to whip off the plastic and it's miraculously all wrapped up in the seaweed.

LTL In Japan, around 1300 years ago, you could pay your taxes with seaweed. And while there've been recent headlines about putting algae in animal fodder to reduce greenhouse gas emissions, people were feeding seaweed to livestock in ancient Greece, Scotland and other places. So, let's head back in time with Dr Pia Winberg, a scientist whose Venus Shell Systems business explores seaweed's many possibilities. She originally recorded the following interview for the Powerhouse 100 Climate Conversations podcast.

PW Seaweed's been around for a billion years of evolution. There's three types. There's brown, which we might know more commonly as kelp; red seaweeds, which nori, even though it looks a bit green and brown, is a red seaweed; and then there's green seaweed, which I predominantly work with, and it is the algae that was the precursor to all plants on land. There's seaweed middens in South America that are 14,000 years old inland, showing that people were walking purposefully, carrying seaweed with them because it was such an essential part of the nutrition and our ability to dry it and walk with it meant that we could bring essential nutrients with us — things like iodine, iron are essential. And then the Māori Battalion, in the Second World War, I think they were the only non-constipated part of the Second World War because they had karengo in their satchels. Karengo is their word for the nori that we know in our sushi today. And even here in Australia, of course, First Nations people, the aunties where I am in local Jervis Bay, I'm having to do scientific research to prove the point of seaweed and health benefits, but they go, ‘Oh yeah, that green seaweed is good for your gut.’ So, it's a bit ironic that we have to pretend that we're doing all this sophisticated frontier research when it's one of the oldest foods on the planet.

ST Hi, my name is Sarah Thomas and I'm the co-founder of South Coast Seaweed with my husband James Thomas. We focus on the revitalisation of traditional knowledge and practices using seaweed. Seaweed was not only an important source of nutrients but also has significant cultural and spiritual connections. It was used in traditional medicine; as a natural dye for textiles; and woven into baskets and other objects. Many believe that seaweed had mythical properties to ward off evil spirits. It was also used in birthing ceremonies and other ceremonial practices like corroborees.

South Coast Seaweed is based in Batemans Bay on the beautiful far south coast of New South Wales. We use a variety of different species, but the prominent one that we use in most of our products is golden kelp. Bull kelp was also used quite prominently by the palawa people. This was eaten fresh or dried as a food source but you can also boil and roast it. It was a staple food for our coastal Indigenous people in many regions because of its high nutrients such as iodine, protein, vitamins and minerals. Kelp was also used to treat various ailments such as colds, coughs and sore throat, and it can be used externally as a poultice for skin ailments and wounds such as oyster cuts.

PW There's no lifespan issue with First Nations people. It's a dietary and lifestyle issue that has been enforced on them. Seaweeds and all of the seafood around there, they’re First Nations knowledge and traditions. 30,000 year old relics exist of giant kelp water carriers from Tasmania and I would say it has to be one of the first pieces of evidence of human use, industrial use of seaweed in that way.

LTL When it comes to seaweed varieties in Australia, there’s plenty to choose from.

PW We've got so many types. I mean, everyone would know about the Neptune's necklace on our foreshores. That's a uniquely Australian iconic seaweed. We need to be proud. It's such a groovy seaweed, Neptune's necklace. And similarly, we have so many others and we don't actually have a lot of the ones that are commercialised in the Northern Hemisphere. So, in the Northern Hemisphere, they're growing a lot of sugar kelp, which is really rich in iodine. And yeah, it's great, but we don't have sugar kelp here. People call me like, ‘Oh, do you have any Irish moss?’ No, I don't, because they grow that in Ireland.

LTL You might have seen Irish moss cough syrup at the chemist. Well, there's a tin of it in the Powerhouse Collection from around 1890. Chemist George Bonnington started producing the remedy in New Zealand decades earlier, with the remedy boldly claiming that public speakers and singers are advised to take Bonnington's Irish moss to sustain the voice. It's one of many Irish uses of this algae, also known as carrageenan. It's also been used to nurse sick calves and offer a nutritional boost during the potato famine.

Irish moss is one of many evocative names for seaweed. There's also Neptune's beard, which resembles guitar strings and is served at Melbourne's Torres Strait Islander eatery Mabu Mabu with pipis, chilli and tamarind. Then there's the aforementioned Neptune's necklace, which botanist Joseph Banks named. It's a seaweed Sarah often sees on the far south coast.

ST That has high anti-inflammatory properties and was traditionally used if you had a toothache or swelling of the gums, as well as stomach pains. You were able to take that seaweed and eat it directly off the rocks, and it would help to alleviate that pain and for the swelling to go down. Another one of my favourite species is the ulva that has skin-regenerative properties and is being used in many different companies across the world for its anti-ageing properties as well.

More Than Apples (1967), Tasmanian Archives A lesser-known industry, which is nevertheless growing in importance, is harvesting of seaweed. Actually, it is sea kelp, which is found along the Tasmanian coastline. A harvesting ship brings in the kelp for processing into sodium alginate. Sodium alginate is used as a thickening and stabilising agent in food and pharmaceutical products.

LTL Dr Pia's research into wound-healing seaweed extracts has a personal element. Her hair once got swept into a drive shaft at her facility, and as she told the ABC after the accident, she had no memory of walking 200 metres back to the lab with her bloody scalp in hand.

PW I'm working with researchers like Fiona Wood, who has developed the skin spray to heal burns victims, and the same time, we're doing clinical study in prison to show how omega 3 from the seaweed is important through the food chain to the brain of prisoners so they don't get so angry so easily, because that's what omega 3 in the brain can help with.

LTL In the Powerhouse Collection, you'll find seaweed in many forms, from 1930s cervical dilators to assist with childbirth and abortions, to old fibre samples from our national science research agency, the CSIRO. Today, the agency's FutureFeed for livestock includes asparagopsis seaweed that lowers the methane produced by Australian cattle. Because methane’s global warming potential can be 83 times higher than carbon dioxide, Dr Zoë Loh from CSIRO's Greenhouse Gas Observations team says reducing methane emissions over the coming decades are critical to reaching net zero emissions and halting global warming.

Seaweed could have global benefits but its cultural importance has long been obvious throughout Japan. On the island of Okinawa, famous for their century-long lifespan of its inhabitants, sea grapes are known as longevity seaweed. In Osaka and Hiroshima, aonori is dusted over savoury pancakes known as ‘okonomiyaki’.

PW In some parts of Japan, 10% of their diet is seaweed by choice because they think it tastes good.

LTL While this algae has been used for millennia around the world, author Kaori O'Connor notes that we often refer to seaweeds by their Japanese name, like ‘kombu’ or ‘wakame’, showing just how closely seaweed is linked to Japan.

ED Kombu I would say, is the most important of all the seaweeds, even though it's maybe not as well known as nori for example, but it's actually the backbone of all Japanese cuisine. It's the most essential ingredient in dashi stock. So if you have eaten anything in Japan, you've definitely tasted kombu. Dashi stock is the base of miso soup. It's the base of so many sauces. If you've ever had noodles, you've probably had dashi, but it plays such a background role that people may not be familiar with kombu. But it's a really, really large leaf-shaped seaweed. They can grow to like eight metres but usually when you buy it in a shop it's already been cut into like a convenient pot-sized shape.

The thing about kombu is that it's also how the world found out about umami. It was the thing that drove a professor from Tokyo’s Imperial University to go, ‘Hang on, what is the thing that's making this soup so delicious?’ Professor Ikeda Kikunae decided he needed to get to the bottom of this and how this kombu in his wife's soup had made suddenly everything taste so much better. He simmered down the kombu dashi till it was nothing, and he isolated the crystals left over and discovered monosodium glutamate. Along with that, he coined the term ‘umami’, which in Japanese means ‘delicious flavour’, and it describes all of the foods that are naturally rich in monosodium glutamate. Things like mushrooms, fermented fish, green tea, but also, like parmesan, tomatoes and, of course, seaweed. I think that discovery is something that has really changed our flavour profile. It changed how people cook.

LTL In 1949, Kathleen Drew-Baker, a scientist from Manchester University, saved the embattled nori industry in Japan's Kyushu region, where the seaweed is also known as ‘gambler’s grass’. She discovered that cultivating the seaweed on oyster shells helped ensure reliable nori harvests at a time of food shortages. In just one season, her research revitalised production in the area. Kathleen died in 1957. She never had the chance to travel to Japan or financially benefit from her findings, however there’s a memorial of her that overlooks the Ariake Sea. Now let's head to Nagano, about three hours north of Tokyo.

ED Fishermen would bring their seaweed up to landlocked Nagano, and over the winter they would freeze-dry a seaweed called ‘tengusa’, which is like a red seaweed. You do this over and over again until it becomes like a very pale sort of colour, and it's dried out, and then you can store it for a very long period of time. This is called ‘kanten’. Kanten is basically a kind of agelatine and it turns whatever's liquid into jelly. Because it sets at room temperature and it doesn't melt away, this is a jelly that you can serve even in the summertime. It'll still hold its shape. It's kind of a genius ingredient. It was actually discovered by accident, when an innkeeper threw out a pot of old soup and then later discovered it was just like a block of jelly. So he realised, ‘Oh, you can actually make things with this.’ It's used in savoury and sweet dishes but it's also being used for like medicines and cosmetics and things, because it has such an interesting texture.

Can Indian Seaweed Replace Plastic? (2023), Insider Business This goo can be made into a plastic-like film that can cover all kinds of food.

Seaweed. It's really softening on the skin, putting it into luxury products. It can be really beneficial for the body.

These bricks are made from seaweed.

ST You can also use seaweed to make sunglasses and different plastics. It's a very mouldable, versatile species that can be used for a range of different products.

LTL In fact, you can stretch and shape seaweed into musical instruments.

ES My name is Emily Sheppard. I am a musician and marine scientist based in Hobart, Tasmania. My journey into instrument making began with kelp, working with bull kelp, which is an amazing material. It's almost like leather when it's freshly washed up, but of course it changes so much once it dries.

LTL So how do you take something from the shore and sea and turn it into an object that makes music?

ES The instrument-making process gave me a really amazing way to connect to the species. To collect the seaweed, you’ve got to figure out which beaches and which reefs have this bull kelp growing on them, and what are the factors that cause that. And it's usually in quite wave-exposed areas. And then also, because you can't just go and cut seaweed out of the water, so I was looking at when the storms were and when it would be likely to be washed up on the beach, and also making sure that it's fresh enough, because after a day or two, it's no longer very workable.

If I hollowed out some of the thicker parts of the bull kelp, it actually created this sort of kelp amplifier. It was quite a slow process of trying to separate some of the layers of this bull kelp, trying to prise them apart, but then without piercing all the way through the kelp. Once it’s prised open, then fill it with sand so that the kelp could dry, but still hold its form, and I would sew the top together so that once it was dried, I would just empty out the sand and it would be in the shape of a pillow. Initially I used this as an amplifier, trying it out with different found objects, and realised that it was sort of like being able to hear the sound of that kelp.

The voice of the kelp or the voice of the sea, it's one of many, many voices. It's a completely different world when you put your head under the water and see the reefs there. I hope that hearing the sound of the kelp helps us to remember this hidden ecosystem.

LTL The Guardian reports that the world's kelp forests are double the size of India. By absorbing carbon dioxide from seawater and the atmosphere, ocean forests may store as much carbon as the Amazon rainforest. But climate change and the marine heatwaves and pest species they bring are threatening these underwater carbon sinks.

ES From the latest research, it seems it's probably not the silver bullet that many researchers had hoped, specifically for carbon sequestration. But there's many broader ecological benefits to various types of seaweed reforestation and possibly seaweed aquaculture, especially with warming waters and species disappearing, such as the giant kelp, which has disappeared at around 95% around Tasmania's coastline. Potentially cultivating seaweed that is more thermally tolerant, or species that may have been from warmer waters that may survive in warmer temperatures is maybe where there'll be some hope in the future.

LTL Worldwide, startups are attempting seaweed alternatives to problematic plastic. From London's Notpla, short for ‘not plastic’, which makes takeaway containers including sauce packets you can actually consume, to Perth's Uluu, backed by the CSIRO and celebrities like Tame Impala's Kevin Parker and model entrepreneur Karlie Kloss.

ULUU (2024) So at Uluu in a nut shell we’re basically fermenting seaweed into this natural plastic-like material.

ST I'd love to see bioplastics grow more in Australia because we are surrounded by water and there are a lot of different types of seaweed that are washing up on the beaches that aren't being used. To create seaweed bioplastics instead of more plastics going into the ocean is an amazing idea.

LTL In the meantime, seaweed can help restore habitats under environmental stress.

ST So back in 2020, the Far South Coast went through the Black Summer bushfires. It was six months of the craziest time of my life. We could see that Country was hurting. We were looking out into the oceans and they were black, and we wanted to understand what sort of damages the bushfires may have had on the ocean, and how we could restore habitat.

I had the opportunity to start working with a non-for-profit group called OzFish, who was doing some seagrass restoration on Conjola Lake, and that's when I started to learn a little bit more about how amazing seaweed was. They're vital for our marine ecosystems because they provide not only habitat and oxygen, but they're carbon sequesters and provide feed for animals. So once James and I had done a little bit of work with OzFish, we started to think a little bit more about how seaweed was used traditionally in Australia and that cultural significance behind seaweed. We started thinking about some of the stories that our grandparents had taught us about using different types of seaweed to catch fish. We wanted to revitalise that for the next generation. Those coastal fishing practices are really important to our people along the far south coast.

Seaweeds are amazing because they derive all of their nutrients directly from photosynthesis and the things around them, and they are the fastest-growing species in the world. It's definitely a low impact, low maintenance way of farming. And I think aquaculture farming of seaweed is going to create some positive change in Australia in and around those commercial fishery industries in the very near future.

PW We're growing seaweed 50 times faster than land crops. It doesn't use any fresh water. We don't have any waste products from it. But not only that, it's putting back essential nutrients that the modern world is deficient in and leads to many of our chronic health issues. Iodine deficiency is still the leading cause of preventable brain damage in the world today, according to the World Health Organisation. I mean, this is serious stuff, and so just a sprinkle of seaweed is a reason for us to be putting it back in our food chain for our brain health.

LTL In 1990s America, McDonalds sold the McLean burger, which used a seaweed extract. Although it was the National Basketball Association's official burger, it tanked. Today, research shows that a seaweed compound could stop the body from absorbing fat. But fast food chain Grill’d is embracing seaweed in its burgers for a different reason: the beef comes from cows fed methane-reducing local red algae.

In Japan, hijiki seaweed is sometimes sprinkled into furikake, a delicious seasoning created as a post-war calcium booster when people were suffering from nutritional deficiencies. There's a lot of hype around hijiki. You might’ve heard that it contains more calcium than milk and is reportedly great for your hair, but food safety bodies around the world have also issued warnings that this brown algae contains an alarming amount of arsenic. So, what does Emiko make of this concern?

ED Honestly, I love hijiki. I did come across information that was warning people against eating it. But to be fair, all of that information comes from Western sources rather than Japanese ones, which I also think is interesting. In Japan, obviously it's a really loved dish. It's a very common ingredient to add to salads and soups and other little, like, sauteed dishes. I think it's like anything that could be slightly toxic. Saffron, for example, in large, large quantities could be toxic, but it's also so expensive you're only using a tiny pinch of it. You're not really going to consume to the level of toxicity.

I have a hijiki recipe in my cookbook. I love it in okara salad with shiitake mushrooms and some carrots and whatever sort of green lying around. Okara is like the leftovers of the tofu-making process, like soybean pulp. It tastes like nothing on its own, but when you add it to dishes, it's really great at soaking up flavour.

LTL If you'd like to hear more about okara and tofu, check out our previous season’s episode on soy. But back to Emiko's okara and hijiki salad.

ED When I was doing this recipe test, I was kind of aware of these warnings against hijiki, and I had that in the back of my mind going, ‘Oh my god, am I going to put this in my cookbook and people are going to complain that I've listed something that's poisonous to eat?’ But when you are making a dish like this, the amount of hijiki that you put in it is a pinch. In this salad that serves like six people, you're not going to be overeating it. It's not going to be such a huge amount that it's going to be dangerous.

LTL It's important not to overdo it with seaweed.

PW You can get into a space where it gets oversimplified and it becomes a solution for everything. Anything humans do, even good things like seaweed, you can do wrong. And that's why we should grow Australian seaweeds. So, pest species and stuffing up ecosystems with new species is a no-no. Don't do that. Each nation has its own amazing species of seaweed, so let's stick with that.

LTL Australia's first commercial kelp farm, Southern Sea Greens, is transforming the invasive wakame species into furikake seasoning, Arnhem Land's South Goulburn Island is experimenting with growing local sea grapes, while native Southern Ocean kombu is turning up in Tasmanian bitters. Also in Tassie, chef Analiese Gregory, whose objects appear in the Culinary Archive, is preserving different kinds of algae with a seaweed press, just like a flower press.

ED I do think that there's a growing acceptance to seaweed. In Italy, where I live for example, it's terrible trying to find Japanese ingredients of any kind, but I can actually find all the different types of seaweed in health food stores. And I think it's because seaweed is really healthy for you. It's just like a sea vegetable, isn't it? But also, the recognition that seaweed has so many medicinal benefits as well, which is how it's always been seen in Japan. It's gaining popularity. It's not really like a household ingredient yet, but I think that people are appreciating it for sure.

LTL Irish moss, Okinawan sea grapes, golden kelp and Neptune's necklace — seaweed appears in so many forms. palawa people fashioned bull kelp into water carriers and Indigenous uses for seaweed include everything from oyster-cut remedies to making baskets.

Kombu is foundational to Japanese cuisine and helped establish umami as the fifth taste we experience after sweet, sour, salty and bitter. Omega 3-rich seaweeds could help reduce aggressive behaviour in prisoners and heal injuries, and the fast-growing algae could be a sustainable nutritious crop, too. So, whether it's carbon absorbing kelp forests, the asparagopsis feed reducing livestock emissions or plastic alternatives shaped from seaweed, one of the oldest life forms on earth could be key to helping us limit the future damage of climate change.

ST Seaweed’s really, really great to pickle and very versatile.

ED One of my favourite ever dishes is temaki. ‘Te’ means hand and ‘maki’ is like a sushi roll. Everything just goes on the table. A little plate of the nori squares, a big bowl of the rice, this beautiful platter with all the different things and everyone makes their own hand roll. The nori stays really nice and crisp. It's great.

LTL This episode was inspired by items from the Powerhouse Collection, such as a 19th century tin of Irish moss and 1879 bottled nori from Japan.