There's a Japanese market on Sawtelle Boulevard with an entire aisle devoted to edible seaweeds. The first time I set foot in that aisle, I couldn't figure out what the differences were among the various plastic-wrapped packages. They all looked identical to me, and yet I wanted to try each one.
I've since learned that nori comes in a wide range of grades, from sheets that cost three-cents apiece, to expensive shin-nori grown in the Ariake Sea. Nori is judged on color (the deeper, the better), aroma, shininess (a prized quality), and softness (the very best nori begin to dissolve as soon as they are set on your tongue; the worst require serious chewing). In this case, price is a fair indicator of quality.
Nori has been cultivated and eaten in Japan since at least the 17th century. During the Edo period, wild red algae were first pressed and dried into sheet form, probably inspired by methods used in Japanese papermaking. Today, commercial production is highly sophisticated and well managed, thanks in part to the work of the British scientist Dr. Kathleen Drew-Baker, who established a comprehensive understanding of the seaweed's life cycle.
The process begins with seeding tiny algal spores on empty seashells set inside temperature-controlled tanks. From there, the young sprouts are transferred to nets suspended on the surface of the ocean. They grow rapidly and can be cut multiple times over the course of the winter harvesting season, although the initial cutting is the most valuable. Once harvested, nori is shredded, pressed onto wire screens, and dried in an oven that hovers just above 100°F. It is then carefully wrapped so that not a drop of liquid can get in. Sealed packages will keep in your pantry for a very long time.
Koreans know nori as gim (also spelled kim). Throughout the British Isles, closely related species of seaweed can be found growing wild along the seashore. These are traditionally harvested and made into laverbread, a Welsh delicacy.
However, the Japanese are by far the greatest consumers of nori, so I tend to follow their lead in terms of how to use it in the kitchen. Sushi is the obvious place to start. Save your finest nori for temaki, hand rolls filled with seasoned rice and chopped raw fish. One way to sample a few different kinds of nori is to quickly turn the dry sheets into chips. You can season them however you see fit -- a dusting of wasabi powder, a shower of sesame seeds, or both.
Makes about 35 chips
For these chips, you can use any kind of nori. Toasted and untoasted sheets will work equally well.
4 sheets nori
Rice wine vinegar, as needed
Toppings: sea salt, wasabi powder, sesame seeds
Heat the oven to 300°F.
Using scissors, cut the nori sheets into smaller pieces. Aim for 2- by 4-inch rectangles, but don't worry if the nori rips in strange directions and you end up with irregular shapes.
Brush each piece lightly with rice wine vinegar, then immediately sprinkle with sea salt, wasabi powder, and sesame seeds.
Transfer the nori to a rimmed baking sheet, spacing the chips so that they do not touch each other. Bake for 15 minutes.
Nori chips are most crisp the moment they come out of the oven. They will loose their crunch over the following 20 minutes to 3 hours, depending on the humidity.