Iceland moss

Overview

Iceland moss, Cetraria islandica, is an upright, leaf-like lichen that resembles a moss. It is a lichen, a partnership of a fungus and an alga, and not a moss or a mushroom. Lichen taxonomy places it in the Parmeliaceae. Carl Linnaeus described it as Lichen islandicus in 1753, and Erik Acharius placed it in Cetraria in 1802.

It is pale chestnut in colour, sometimes greyish-white, and grows to about 7.6 to 10 cm, with flattened, fringed lobes. It is an Arctic-alpine species found in northern mountains and on the lava slopes of western and northern Iceland, and it also grows in northern Britain and Ireland and across the Arctic of North America.

Constituents

Lichenin, a starch-like polysaccharide, makes up about 70 per cent of commercial material and is the reason the lichen thickens liquids. The bitter taste comes mainly from cetraric acid. Other constituents include fumaric acid, lichenostearic acid, lichesterinic acid and protolichesterinic acid, with thallochlor, a modified chlorophyll, giving the colour.

Food use

All parts of the lichen are edible, according to Wikipedia. The dried lichen is soaked before use, and boiling reduces the bitterness. As a thickener it can be added to milk or grain dishes, and it can be dried and stored for later use.

For centuries it was used widely in breads, porridges and soups in Iceland and other northern countries. Its use has since declined, and it now appears mostly in folk remedies and in a few Icelandic dishes. The catalogue records the historical use as processed for breads, porridges and soups, and it marks the individual record for inspection because the traditional processing and the compound exposure both need separate research.

Safety

The sources read here do not establish a safety assessment for regular food use of Iceland moss. Wikipedia gives no explicit safety warning, and the catalogue asks for the traditional processing and compound exposure to be researched before any use is recommended. Medicinal use, which the sources connect with cetraric acid as a bitter tonic, is outside the scope of this food record.

This page does not give a dose, a preparation for daily eating, or a verdict that the lichen is safe to eat.