1 October 2019


Two books about edible seaweeds recently arrived on the editor’s desk. Ocean Greens by Lisette Kreischer and Marcel Schuttelaar (The Experiment) explores the world of edible seaweed and sea vegetables and includes 50 vegan recipes. Bren Smith’s Eat Like a Fish (Murdoch Books) is more of a rollicking tale of the adventures of a fisherman turned restorative ocean farmer growing edible algae. They have inspired us to take a closer look at these “vegetables” that are used as ingredients and flavourings in sauces, soups, salads, stews and side dishes and as sources of food additives such as carrageen (a thickener), and agar agar (a gelling agent).

Ocean Greens        Eat Like a Fish

WHAT ARE EDIBLE SEAWEEDS? They are marine algae. There are more than 20,000 species of algae and humans have enjoyed hundreds of them for thousands of years. They have been especially important foods through coastal Asia, in the British Isles, and places as different as Iceland and Hawaii says Harold McGee in On Food and Cooking. There are three broad groups: green, red and brown.
Seaweed salad
WHAT’S IN SEAWEED? Seaweeds absorb nutrients from water. Fresh seaweed is around 70–90% water, 6% protein and 5% carbohydrates (including dietary fibre) and has negligible fat. They are rich sources of some vitamins and minerals. Importantly, they are a good source of iodine, a naturally occurring mineral that is needed by the thyroid gland to synthesize thyroxine, an important hormone that regulates metabolism. They also can absorb toxic metals so they are regularly monitored by Food Standards organisations.

HOW DO YOU PREPARE THEM? Some seaweeds can be eaten raw; others are better cooked, dried, baked or roasted. Here’s what Lisette Kreischer and Marcel Schuttelaar recommend:

  • Fresh seaweed: rinse thoroughly, then gently squeeze out any excess water and pat dry with paper towels. 
  • Dried seaweed: Soak following the packet instructions. It expands considerably when rehydrated. For example, 5g dried wakame equals 40–50g fresh. 
Good Carbs Cookbook author, Kate McGhie, recalls her Mum and Nan often used seaweed as a substitute for lettuce or spinach in salads. They combined it with crisp chopped apple, golden shallots and sometimes shredded cabbage and nuts for contrast all tossed in a tangy dressing. Yotam Ottolenghi is a seaweed fan. “Sea lettuce and aonori (green laver) are the most widely used of the green group – sea lettuce in salads and soups, aonori in powdered form,” he says. “Red algae, meanwhile, tend to have a deeper, sulphur-like aroma. Nori, the most common of these, is the traditional sushi wrapper, while dulse – a purplish leaf that turns green when cooked – develops a distinct aroma of bacon when fried. The generally milder brown algae include in their number kelp, kombu (essential in dashi) and wakame, the vibrant green leaves in miso soup and in salads.”

HOW MUCH SEAWEED SHOULD YOU EAT? The authors of Ocean Greens, Lisette Kreischer and Marcel Schuttelaar, recommend consuming edible seaweeds in moderation as part of a diverse and well-balanced diet. They suggest around 5–10g dried seaweed a day is plenty.

WHAT SEAWEED IS THAT? It’s easy to get confused as there can be numerous common names for the same product. We have put together this simple guide for GI News readers.

Brown algae
The main uses of brown seaweeds are as foods and sources for alginates.

Red algae
The main uses of red seaweeds are as foods and sources for agar and carrageen.

Green algae
The main uses of green seaweeds are as foods.

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