Winter Kelp Chowder: The Forest in a Bowl

Chowder is the most forgiving frame a cook can build around seafood: potatoes for body, dairy for softness, something saline and briny for depth. Swap the clams for kelp — or better, use both — and you get a soup that tastes unmistakably of the cold ocean forest without asking you to love seaweed first. Kelp in chowder is a texture and a seasoning: silky ribbons, gentle brine, and a quiet umami that makes the potatoes taste more like themselves.

This recipe feeds six generously, takes about fifty minutes, and works with fresh, frozen or dried kelp. If you have not cooked fresh kelp before, read our guide to preparing fresh kelp first — blanching is the step that turns a rubbery blade into a silk ribbon.

Which kelp, and how much

You want a tender-bladed kelp, not a wrack. Best options, roughly in order:

• Sugar kelp (Saccharina latissima) — thin, sweet when blanched, cooks in minutes. It is the species behind our sugar kelp profile, and it is increasingly farmed on cold-water longlines in both hemispheres.
• Wakame (alaria if in the North Atlantic) — similar tenderness; the rib is edible once blanched.
• Bull kelp blades — the flat fronds off the stipe, thinly sliced; sturdier, so give them a longer simmer.
• Dried kombu or wakame, reconstituted — perfectly good in winter when fresh is unavailable. Soak dried seaweed in cool water for ten minutes, then slice. Reserve the soaking liquid and let it stand in for part of the stock.

Quantity: about 250 g fresh kelp ribbons (a heaped colander-full after blanching), or 40 g dried. Kelp shrinks and relaxes as it cooks; what looks like too much becomes exactly right.

The crucial prep step

Fresh kelp blades arrive coated in a slick algin film and, depending on harvest, a dusting of harmless epiphytes. Rinse well, then blanch in unsalted boiling water for 60–90 seconds — the blades flash from brown to emerald — and drain. This sets the colour, tames the iodine edge and tenderises. Slice into ribbons two centimetres wide. Blanched kelp keeps two days refrigerated, so you can prep ahead.

The chowder blueprint

Every good chowder follows the same architecture: render something savoury, sweat aromatics, add potatoes and liquid, simmer to tenderness, finish with dairy and the sea things in the last minutes. Kelp follows the clam playbook — it goes in late, because overcooked kelp loses its silk and goes stringy at the edges.

A note on liquid: a light seaweed vegetable broth instead of plain stock doubles down on the ocean character without fish sauce or clam juice. Plain fish or vegetable stock works perfectly well.

Winter kelp chowder (serves 6)

Ingredients

• 60 g butter (or 3 tbsp oil)
• 1 leek, white and pale green only, halved and sliced
• 1 onion, diced
• 2 celery stalks, diced
• 3 garlic cloves, minced
• 2 bay leaves; 1 tsp fresh thyme leaves
• 700 g waxy potatoes, cut in 2 cm chunks
• 1 litre seaweed-vegetable broth, fish or vegetable stock
• 250 g blanched kelp ribbons (see above)
• 250 ml whole milk; 250 ml cream (or 500 ml milk for a lighter bowl)
• 300 g smoked fish (haddock, trout or mussels), flaked — optional but lovely
• Juice of ½ lemon; salt and plenty of black pepper
• To serve: chopped parsley or chives, toasted rye, seaweed salt at the table

Method

1. Melt the butter in a heavy pot over medium heat. Sweat leek, onion and celery with a pinch of salt for 8–10 minutes until soft and sweet, not browned.
2. Add garlic, bay and thyme; cook one minute. Add potatoes and stock, bring to a bare simmer, and cook 12–15 minutes until the potatoes are just tender.
3. Crush a ladleful of potatoes against the pot's side and stir back in — this is your thickener. No flour needed.
4. Reduce heat to low. Stir in milk and cream, then the kelp ribbons and smoked fish. Warm through for 4–5 minutes without boiling (boiling dairy splits and kelp toughens).
5. Off the heat, add lemon juice, taste, and adjust salt and pepper. Rest five minutes before serving — chowder finds itself in the pause.

Serve hot with toasted rye and a pinch of seaweed salt over each bowl.

Variations worth your winter

• Corn and bacon: render 100 g diced bacon as step zero and add two cups of corn with the potatoes. Smokier, sweeter, and the one to convert sceptics.
• Full seafood: add mussels or clams in the shell at step four, cover until they open, and let the kelp play supporting role.
• Vegan forest chowder: olive oil instead of butter, oat cream instead of dairy, and a strip of kombu simmered with the stock then removed. Add a tin of butterbeans with the potatoes for substance. The kelp carries it — this version needs no apology.
• Green chowder: blend a third of the soup with a handful of blanched kelp and parsley and stir back in for a deep green, forest-through-fog colour.

Sourcing kelp in winter

In the northern hemisphere, fresh kelp is a spring-to-autumn crop, but farmed and blanched frozen kelp is available year-round in good fish shops and from online seaweed farms — our guide to buying seaweed sustainably explains what to look for and which certifications matter. Frozen kelp thaws straight into the blanching water. Dried is the reliable pantry fallback and, reconstituted, is indistinguishable in a soup this hearty.

Do not forage fresh kelp for the pot in winter storms, and never take a living plant by the holdfast — if you forage at all, take cast blades from high on the beach and check local rules first.

Key takeaways

• Use tender-bladed kelp — sugar kelp, wakame or young bull kelp blades — blanched 60–90 seconds before slicing.
• Kelp goes in late, like clams: the last five minutes, never boiled hard.
• Crushed potato, not flour, is the cleanest thickener.
• Dried kombu or wakame, reconstituted, makes this a true year-round winter soup.
• 250 g of fresh kelp feeds six; buy farmed kelp when you can.

FAQ

Can I use dried kelp instead of fresh?

Yes. Soak 40 g of dried wakame or shredded kombu in cool water for ten minutes until supple, slice into ribbons, and use exactly as the blanched fresh kelp. Add the strained soaking liquid to the pot as part of your stock — it holds a lot of flavour.

Why did my kelp turn out tough and stringy?

Two causes: it was not blanched first, or it boiled hard in the dairy stage. Blanching tenderises the blade; a hard boil afterwards tightens the alginates back up. Keep the finished chowder below a simmer and the ribbons stay silky.

Is chowder kelp safe to eat in quantity once a week?

For most people, yes — a serving in a shared pot is modest. The variable is iodine, which is high in some kelps; blanching reduces it meaningfully. If you have a thyroid condition, check with your doctor, and see our seaweed nutrition guide for the numbers and sensible weekly amounts.

Can I freeze leftover chowder?

You can, though dairy-based soups sometimes grain slightly on thawing. Freeze before adding the milk and cream if you are planning ahead; finish with dairy after reheating. Kelp itself freezes and reheats without complaint.

What wine or drink goes with it?

Something cold and acid: a dry cider, a fino sherry, or a lean white like albariño. Hot black tea with a slice of lemon is the winter-honest non-alcoholic answer, and nobody at the table will argue.