Important: Safety Warning
This page prescribes plants as medicine according to pre-modern medical theory. Several of the plants named are toxic, correct identification is difficult, and the doses given have no scientific basis. Do not ingest or apply any preparation described here.
This information has been left in for historical purposes but should not be acted upon.
Home › The Nursery and Sick-Room › DECOCTION OF ICELAND MOSs
DECOCTION OF ICELAND MOSs
Boil 5 drachms of Iceland moss in 1½ pints of water down to a pint, and strain. Used in consumption and dysentery. Dose: 1 to 2 ounces.
A sick-room preparation rather than a dish, but it is still a set of instructions for making something to drink. The measurements are apothecary, not kitchen.
- DrachmsAn apothecary drachm is one-eighth of an apothecary ounce, roughly 3.9 g, so 5 drachms is about 19-20 g of dried moss. Dry lichen is extremely light and bulky; that weight fills a surprisingly large measure.
- PintsIf the book is British, 1½ imperial pints is 30 fl oz reduced to 20. If American, 24 fl oz reduced to 16. Either way the point is reducing by a third, which is what you should watch rather than the clock.
- Iceland mossNot a moss but the lichen Cetraria islandica, still sold dried by herb suppliers and eaten as a food in Iceland. It carries bitter lichen acids, which is why traditional practice soaks it in cold water, sometimes with a pinch of baking soda, and discards that water before decocting.
- The textureIceland moss is usually given as roughly half lichenin and related starches, so a strong strained decoction sets to a weak jelly as it cools; reheat gently to make it pourable again.
- Simmer, do not boil hardA slow simmer gives the mucilage time to come out of the lichen, whereas a rolling boil reaches the target pint before much has been extracted, and risks scorching the residue at the bottom of the pan.
- StrainingPress the softened lichen against the sieve to recover the thickened liquid, which clings to the plant material. A jelly bag or muslin gives a cleaner result than a metal strainer.
- Yield and doseAbout a pint, with a stated dose of 1 to 2 fluid ounces, that is 2 to 4 tablespoons. Made without preservative it should be treated like any thin broth and kept refrigerated for a day or two at most.
- The medical claimConsumption meant pulmonary tuberculosis, and this decoction does nothing for it or for dysentery. Read the entry as a demulcent drink for a sore throat and a historical document, not as treatment.
Iceland moss earned its place in nineteenth-century sick-room chapters through the apothecary rather than the cook. It appears in European pharmacopoeias from the eighteenth century onward as a bitter mucilaginous drug, prized because a lichen that grows on bare northern ground could be dried, stored indefinitely and boiled into something nourishing and soothing. In Iceland itself it was genuine famine and everyday food, washed, dried and beaten into flour for bread and porridge or cooked with milk. By the time this book was compiled, the sick-room section of a general household manual still carried a residue of the domestic dispensary: decoctions, gruels, barley waters and beef teas, set down in apothecary drachms and doses because the housewife was expected to compound them herself. Its reputation against consumption was traditional and never demonstrated, and that reputation receded as tuberculosis came to be understood as a bacterial disease, though the drug itself lingered in a number of pharmacopoeias as a demulcent well into the twentieth century.