Overview

Kelp refers to large brown seaweeds (Phaeophyceae) in the order Laminariales, comprising about 30 genera. It grows in dense underwater forests in cold, nutrient-rich shallow oceans and is a foundational ingredient in East Asian cuisines, valued for its umami-rich glutamates and mineral density. The flavor is savory and oceanic, with a mild sweetness when simmered.

Origin and history

Kelp is thought to have appeared in the Miocene epoch, 23 to 5 million years ago [1]. It requires water temperatures between 6 and 14 °C (43 and 57 °F) and is found in temperate and polar coastal waters worldwide. Human use of kelp as food is documented in East Asia for at least 1,500 years, with Japanese records from the Nara period (710–794 CE) noting dried kombu as tribute from Hokkaido [1]. In Korea, kelp (dasima) has been used in broths and soups for centuries, and in the Philippines, certain kelp species are harvested for salads and pickles [2]. The global kelp farming industry expanded significantly in the 20th century, with China, Indonesia, and South Korea as top producers.

Varieties and aliases

  • Kombu (Japanese): Dried kelp, primarily from Hokkaido. Major cultivars include ma-kombu (Saccharina japonica), rishiri-kombu (S. ochotensis), and hidaka-kombu (S. longissima) [1].
  • Dasima (Korean): Dried kelp used in Korean cooking, typically Saccharina japonica.
  • Haidai (Chinese): Dried kelp used in Chinese soups and braises.
  • Sugar kelp (Saccharina latissima): A species common in the North Atlantic.
  • Bull kelp (Nereocystis luetkeana): A Pacific species used in some Indigenous North American cuisines.

Culinary uses

Kelp is most commonly used dried, which concentrates its flavor and extends shelf life. In Japanese cuisine, kombu is the foundation of dashi, a vegetarian stock made by steeping dried kelp in water, often with katsuobushi (bonito flakes) [1]. In Korean cuisine, dasima is simmered with dried anchovies to make myeolchi-dasima yuksu, the base stock for soups like doenjang jjigae (soybean-paste stew), kalguksu (knife-cut noodle soup), and odeng (fish-cake skewers in broth). Kelp is also pickled, used in salads, or ground as a seasoning. Fresh kelp can be blanched and eaten as a vegetable.

Cross-cuisine context

Kelp has no widely recognized analogue in Mexican cuisine. The closest functional parallel is the use of dried seaweed in Japanese and Korean broths, which serves a similar umami-building role to that of dried shrimp or fish heads in Mexican caldos. In the broader LA-relevant corpus, kelp appears most prominently in Japanese and Korean cooking. In Japanese cuisine, kombu is the primary dashi base. In Korean cuisine, dasima is paired with dried anchovies for a foundational stock that underpins jjigae, guk, and tang dishes. In Filipino cuisine, certain kelp species are used in ensaladas and pickles, though less centrally than in Northeast Asian traditions [2].

Notes for cooks

  • Dried kelp should be wiped with a damp cloth, not rinsed, to preserve surface umami compounds (white powdery bloom is natural glutamates).
  • Simmer kelp gently; boiling can release bitter compounds and a slimy texture.
  • Store dried kelp in an airtight container in a cool, dark place. It keeps for months.