Photo by Marla Aufmuth
Kombu is the Japanese term for the genus Lamaria, a category of brown algae or "kelp." There are many varieties: winged kelp, sugar kelp, horsetail kelp, Devil's Apron... The leaves are often large and leathery; it’s all edible, but some have better tastes and textures than others.
Step 1: Check Your Tide Book
Collect seaweed when the tide is low. Once it’s dry on the beach, insects may be breaking it down, so collect in the water, just below the tide line. Avoid any that look like something has been chewing on them.
Step 2: Snip Sparingly
Don’t yank seaweed from the rock it’s anchored to. Kombu has about five or six "fingers" or leaves on it. Don't snip more than a few off. A good rule of thumb when wild crafting is to never take more than 1/3 from each plant so it can grow back.
Step 3: Rinse Off in Ocean and Trim Messy Ends
The cold, flowing salt water is a good place to first rinse the seaweed. Remove any grit or living creatures like snails. Trimming the ends is easiest when it's wet, and there's no point in carrying added weight back. (But if you do trim them later, they make great fertilizer for your garden.)
Step 4: Rinse With Fresh Water and Store
I've heard a lot of debate about whether or not your should rinse seaweed in fresh water. Some people claim it takes away the saltiness. Other's have said it shocks them into producing more salt. And some people think it makes no difference. I do rinse with fresh water, and then dry on a pasta rack or my laundry line. Then you can store these in a plastic bag for a really long time. (Over a year and still counting).
I'm going to be posting more instructables on using kombu, but to start, you can check these out.