Sea lettuce is a tasty green algae that looks just like its namesake. It prefers less salty water, so look for it further inland in Denmark's fjords, where it grows on rocks or floats freely in the water.
Where to find it
Like other seaweeds, sea lettuce can grow on rocks, but it is also wholly capable of living as a free-floating mass in open water. Seeking shelter from the wind and currents, free floating lettuce prefers shallow coastal waters, especially if they are nutrient rich. In fact, an unusually large amount of sea lettuce in one spot may be an indication that there’s a sewage pipe nearby.
When to find it
Sea lettuce tastes best in early spring. At the end of summer, it forms spores and turns a yellowish color before finally decomposing.
Leaves: April, May, June, July, August.
How to Spot It
Sea lettuce looks like a large bunch of curly-leaf lettuce. The free-floating version that bobs on the ocean waves can develop giant leaves up to a square meter in size. The leaves of sea lettuce that anchors directly onto underwater rocks are much smaller; rarely do they exceed 20 cm in length.
How to Pick It
It is best to pick fresh leaves directly from the rocks.
On the palate
Sea lettuce has a fresh, sweet ocean flavor—-often laced with clear notes of iron—-and a pleasantly soft and supple texture. It gets tougher and takes on a stronger flavor once dried.
Sea lettuce has no particular scent.
A lot of sand, mud, small shells, and snails can hide among the ruffled leaves of sea lettuce, so be very thorough when washing it. It tastes great raw, but is also good cooked. Just don’t freeze it, as that will turn it bitter.
You can use sea lettuce as an ingredient in salad, risotto, or soup. You may want to marinate the green leaves before adding them to your dish. The large leaves are also ideal for wrapping around fish or shellfish before poaching or grilling. You can substitute dried and ground sea lettuce for parsley or other herbs.
Store fresh sea lettuce in a sealed bag or airtight container inside the crisper drawer of your refrigerator. Place a moist dishcloth over it to keep it fresh and crisp. Rinsing the lettuce with fresh water will reduce its shelf life. If you want to store it for more than a few days, you’ll need to dry it and store it in an airtight container. Once rehydrated, the lettuce will keep for one day in the refrigerator.
Sea lettuce can be replaced with sea cellophane, which is thinner, lighter, and smaller than sea lettuce.
Risk of misidentifying the plant
There is no risk of mistaking the plant for another dangerous or undesirable plant.