A Beginner's Guide to Foraging and Cooking Seaweed

Shame was what made me do it. My uncle, whom I idolized, tossed a mop of rockweed at me after a swim and I shrieked. He told me to stop being such a baby, and later, when he needed seaweed to top off the lobster boil, he sent me to the beach to get it, alone, which, with a pounding heart, I did. When the lobsters were red, he dipped a mug into the pot for broth to rinse the steamers. He took a sip, then passed it to me like a flask, and I liked seaweed for the first time of a million. Since then, I’ve consumed seaweed in almost every way I can think: food, drink, nutritional supplement, skin soother, livestock feed, and garden fertilizer. If you’re skeptical, let me suggest you start with the pudding.

How To Forage For Seaweed Conveniently, every seaweed found in North American waters (salt, not fresh) is technically edible, but only a handful taste good enough to be called food. There are a few to avoid in the genus Desmaresdia, dubbed “sourweed” because they’re loaded with sulphuric acid. These won’t feel good in the gut if you eat too many, but they taste so caustically sour that you’re unlikely to swallow even one. While there are hundreds that we could eat, there are three that are abundant on both coasts and really easy to love in the kitchen: wakame, kombu, and Irish moss.

If you want to brave the waves to collect your own, there are a few important things to consider before you dive in. You want to make sure the water is clean, as seaweeds are powerful bio-accumulators and will suck up any sludge that’s contaminated the water. Next, you want to make sure it’s legal, as it is a regulated “fishery.” Here in Maine, a person can harvest 50 wet pounds per day for personal use, but every state has different regulations.

You also want to make sure you know how to legally access your shoreline. Landowner relations, especially on the waterfront, can be tenuous, and we need to be good and diligent stewards of these places and these relationships. To do this means that you also need to be versed in how to ethically harvest each species. These harvest guidelines from the Maine Seaweed Council are a great reference, but your state may have its own. Lastly, be safe. You’re not taking a lazy walk on the beach for the storm drift that’s piled up on the sand, that stuff is for fertilizer. The stuff you want to eat is attached to the rocks getting pounded by waves at the low tide line, so bring a buddy.

Most seaweeds thrive in the rocky, churning places of the lower shore. On big low tides, like on a full moon or after a storm, we can reach these places on foot, but often, you’ll need a boat, and no matter what, you’ll need some serious sea-legs, as can be seen here in this video of Larch Hansen, Maine’s own “Seaweed Man.” While I’m normally the loudest cheerleader for people foraging their own food, seaweed is one that I just as enthusiastically encourage purchasing from small, thoughtful, wildcrafters like Larch, who have been stewarding the same seaweed beds for years. No matter how you get the seaweed to your kitchen, just get it there. Once you’ve got your hands on some, you can use it fresh or air-dry it and it’ll last for many years in a dark pantry.

Irish Moss (Chondrus crispus) If you close your eyes and picture the quintessential tidepool, your brain probably paints in a pretty, red, cluster of fronds waving around on the side of a rock. This is Irish moss, and you want to make pudding with it.

Irish moss is the easiest to harvest and is often reachable on foot. You’ll find it clinging to the sides of rocky outcroppings and ledges from middle tide to beyond low tide. It clings to the rocks with a small holdfast and branches out in many forked fingers, forming a clump that looks like a small head of frilly, red lettuce. It’s loaded with a polysaccharide called carrageenan, which is used in all kinds of products as a thickener, and this is what will make your pudding set up. Irish moss pudding, also known as sea moss pudding, or blancmange, is not meant to taste like seaweed but uses just enough to milk it for its gelling properties. This dessert has been around forever so there are lots of historical recipes to follow, but my favorite recipe comes from Micah Woodcock, one of the harvesters I buy from, where he’s added the touch of blending the chilled pudding for a beautiful whipped mousse finish. The carrageenan can also be extracted in hot water and chilled into a clear gel that can then be used to thicken smoothies, hot drinks, soups, sauces, and anything else you want to give a silky texture.

Dulse (Palmaria palmata) Dulse is the jerky of the sea. You don’t need to add a single thing to it to make it delicious. Every coastal culture that has access to dulse reveres it as a salty snack. You can find it waving its long red fingers from middle tide to below the intertidal zone, clinging, often in crevices, to rocks by a little disc and then fanning out in the way that fingers do from a palm.

Dulse can be air-dried and snacked on, as-is, or crushed into flakes and added to soups, rice, beans, salad dressings, ground into salt or compound butter, or anything you want to add an additional salty depth of flavor.

Wakame (Alaria esculenta) “Esculenta” means delicious, and that’s no lie. If I could only eat one salad for the rest of my life, it would be a wakame salad. It’s deeply nourishing and addictively snappy. Boiled, chilled, and tossed with cucumbers, scallions, rice vinegar, sesame oil, and a splash of maple syrup, it’s my go-to summertime lunch. It’s the most versatile in the kitchen, from fermented kraut, to a pot of creamy white beans, to delicately poached fish, wakame adds something special to them all.

You’ll find wakame growing in the choppiest conditions, farther out than the others, and aside from being able to walk to the end of the occasional rocky peninsula, you’ll probably need a boat to get to it. It’s got a holdfast like an eagle claw that grabs onto rocks and does not let go. It grows, from there, a long, flat, slender stipe that continues as a midrib through the center of a long frond, up to 12 feet long, with frilly edges. This midrib sets it apart from many other long slender kelps, as do the “wings” at the base of the blade, which should be left intact to ensure the next year’s growth.

Kombu (Laminaria digitata) If you need more umami in your life, (and who doesn’t?) kombu is where you’ll find it. And you’ll find the kombu in the rough waters beginning at the very lowest tide line. Check your rocky shorelines at a full moon low tide, or after a big storm and you might spot some that you can get to on foot. Otherwise, get your paddles.

It’s got a similar, clawlike holdfast to wakame, but the stipe is round and the blade is very wide with no midrib, and it separates into long fingers, the whole thing up can be up to 5 feet long. A little kombu goes a long way, and just a few fronds are enough to get me through a year.

Dashi is my favorite thing to make with it, but I also throw a handful of dried kombu into just about every pot of soup, stew, or beans. Dashi used to sound intimidating to me, like a lot of exquisitely simple Japanese cooking does, but the simplicity of dashi is not a mirage, it’s actually really easy—a simple broth of just three ingredients: kombu, bonito flakes, and water. The resulting flavor is one of the most foundational sources of umami that we know. It’s mainly used as a base for miso and other soups, but also levels up anything that calls for a cooking liquid like stock. Your rice, grains, braised vegetables, poached fish, and ramen broth will all thank you for using dashi instead of water.