Overview

Macroalgae, commonly called seaweed, are macroscopic, multicellular marine algae belonging to three broad groups: red (Rhodophyta), brown (Phaeophyta), and green (Chlorophyta). They grow in coastal waters worldwide and are harvested for food, thickeners, and condiments. Their flavors range from briny and oceanic to subtly sweet or umami-rich, depending on species and preparation.

Origin and history

Seaweed has been harvested for food for thousands of years, with the earliest documented use in East Asia, particularly in Japan, Korea, and China, where species such as nori, kombu, and wakame became dietary staples [1]. Commercial cultivation of seaweed began in Japan in the 17th century, and today the global seaweed industry is dominated by farmed species, especially in China, Indonesia, and South Korea [2]. In the Philippines, seaweed is a key ingredient in dishes such as ensaladang lato (seaweed salad) and is also processed into carrageenan for the global food industry [3].

Varieties and aliases

  • Nori (Porphyra spp.): thin, dried sheets used for sushi and snacks
  • Kombu (Saccharina japonica): thick brown kelp used for dashi broth
  • Wakame (Undaria pinnatifida): tender brown seaweed used in soups and salads
  • Dulse (Palmaria palmata): red seaweed eaten raw, dried, or fried
  • Irish moss (Chondrus crispus): red seaweed used as a thickener and in desserts
  • Sea lettuce (Ulva spp.): green seaweed with a mild, lettuce-like texture
  • Ogo / limu (Gracilaria spp.): red seaweed popular in Hawaiian and Filipino cuisine
  • Cochayuyo (Durvillaea antarctica): brown kelp eaten in Chile and Peru [2]

Culinary uses

Macroalgae are used in broths, salads, soups, snacks, and as wrappers. Kombu is simmered to make dashi, the foundational broth in Japanese cooking [1]. Nori is toasted and used to wrap sushi rolls or crumbled as a garnish. Wakame is rehydrated and added to miso soup and sunomono (vinegared salads). In the Philippines, fresh lato (Gracilaria) is dressed with vinegar, tomatoes, and onions for a raw salad [3]. In Chile, cochayuyo is boiled and added to stews or salads [2]. Dried seaweed is also ground into flakes and used as a seasoning, often paired with sesame, soy sauce, or citrus.

Cross-cuisine context

Macroalgae do not have a direct analogue in traditional Mexican cuisine, where land-based greens such as quelites (wild greens), verdolagas (purslane), and romeritos (a type of sea-blite, sometimes confused with seaweed) fill a similar role as foraged or cultivated leafy vegetables. Romeritos, despite their name, are not seaweed but a halophytic plant (Suaeda spp.) that grows in saline soils and is traditionally cooked in a mole-like sauce for Lenten dishes. The functional comparison is closer to quelites: both are gathered from the wild, cooked simply, and valued for their mineral content and seasonal availability.

In Korean cuisine, macroalgae are central: gim (nori) is used as a wrap for rice, miyeok (wakame) is essential in birthday soup (miyeokguk), and dasima (kombu) is used for broth [1]. In Japanese cuisine, the three primary seaweeds (nori, kombu, wakame) form a foundational triad for soups, stocks, and sushi. In Filipino cuisine, lato and other seaweeds are eaten fresh in salads or cooked in coconut milk, bridging the raw and cooked seaweed traditions of the Pacific [3].

Notes for cooks

  • Dried seaweed keeps for months in an airtight container away from light and moisture. Once rehydrated, use within a few days.
  • Kombu should be wiped with a damp cloth, not rinsed, to preserve its natural white powder (mannitol and glutamates) that contributes umami.
  • Nori sheets lose crispness quickly after opening; reseal tightly or toast briefly over a flame before use.