All about seaweed

Seaweed is not one plant but a family of marine algae, divided into three groups by colour: brown, red and green. Around 500 species grow along the Norwegian coast. They have no roots, no flowers and no soil — they hold onto rock and take everything they need from the water moving past them. That is also why where they grow matters so much to how they taste.

Meet the species we harvest

Kelp is seaweed, but not all seaweed is kelp. Kelp is a particular order of large brown seaweeds — the ones that grow into underwater forests, with a holdfast gripping the rock, a stalk, and long blades. Our Kombu and Sugar Kelp are kelps; Nori and Dulse are red seaweeds and are not.

In Norwegian the split is tidier: tare is the kelp, tang is the smaller seaweed of the shoreline that spends part of its day out of the water.

The full difference

Umami is the fifth taste, alongside sweet, sour, salty and bitter — the deep savouriness of aged cheese, tomatoes, cured ham and good broth. Seaweed is full of the naturally occurring glutamates that trigger it, which is why a pinch makes food taste more of itself rather than more of the sea.

Umami, umawhat?

Yes — in the quantities people actually cook with. A pinch of seaweed salt on your eggs is a different thing from a bowl of kelp, and the limit that matters is iodine rather than seaweed itself. The recommended daily intake of iodine is 0.15 mg and the upper daily limit 0.6 mg, so with our strongest products a teaspoon is already a generous day's worth.

Each product carries its own iodine figure on the pack and the product page, so you can do the sum for what is in your cupboard.

The longer answer

It is unusually dense in minerals for a food you use by the pinch — iodine above all, plus calcium, iron and fibre. We would rather be straight with you than oversell it: seaweed is a seasoning and a vegetable, not a supplement, and the exact content shifts with the species and the season it was cut in.

[Needs your decision on which claims to make here. Your two iodine articles currently contradict each other, so this answer should be written once and then be the only version.]

It varies more than twentyfold across our range, from 1.14 mg per 100 g in the Tagliatelle to 38.35 mg in Arctic Ocean Greens. Kelps are the richest of all, which is why we recommend blanching Kombu and Sugar Kelp before eating them — thirty seconds in boiling water can cut their iodine by up to 90 per cent.

If you have a thyroid condition or take iodine supplements, talk to your doctor first.

Iodine and thyroid function

By hand, with a knife, at low tide. We cut the blade and leave the holdfast and growing point behind, so the plant regrows from where it was cut — the way cutting grass is not the same as pulling it up. We rotate the areas we work, record what we take from where, and report our catch. It is slower than trawling, which is the point.

Wild, not trawled

We harvest in the tidal flow of Nappstraumen, away from settlement, industry and run-off, in cold Atlantic water that the Gulf Stream keeps moving. Moving water is the thing that matters: nothing sits still long enough to accumulate.

[Do you test, and what for? If you have results, this is the answer that earns the most trust on the page.]

[Needs checking before this page goes live. Debio and EU Organic are claimed on one product only, Arctic Ocean Greens, and the Seagreens mark on your Our Seaweed page appears nowhere in product data. Say what you are certified for, and on which products.]

Please do — it is the best way to understand a coastline. But what you pick, where you pick it and how you cut it all matter, both for you and for the plant. We wrote the guide we wished we had had: identification, responsible cutting, drying, and a few recipes for what you bring home.

Pick your own seaweed