"Lettuce" sounds the same in most European languages, which derive their word from the Latin lactuca. Lac meant milk to the Romans, and the slashed stem of a wild lettuce secretes a viscous, creamy sap. The suggestive appearance of this substance, and lettuce's annual tendency to bolt shoots of exceptional firmness and length, gave the vegetable a reputation as an aphrodisiac in ancient Egypt and after. "Perhaps it will put sap in your pizzle," says Trevor Howard as a soldier sits before a head of lettuce in the 1968 film The Charge of the Light Brigade.
The Romans better understood lettuce's true qualities. Its waxy secretion resembles and smells like the latex of the opium poppy, and it too has a mildly soporific effect. During the early stages of the Roman empire lettuce was eaten at the end of a meal to calm diners and help them sleep. As the centuries progressed and the citizens gave themselves up to lust and debauchery, they spurned lettuce as a food fit only for the savages of the continent beyond. Perhaps they thought it boring, and by then they had other narcotics in any case.
Lettuce originated in the Mediterranean basin, one of the vast Asteraceae or Compositae family that includes chicory, endive, certain thistles and a few tough-leaved plants such as dandelion. Many young shoots are edible in temperate Europe during spring, and wild lettuce must have been a relief after the privations of winter. The Sumerians were growing it by about 4,000BC, and the Greeks enjoyed it too. No lettuce recipes survive from the dark ages, but at least by the 1300s it had settled in Britain in its traditional role as a salad leaf. The summoner of the Canterbury Tales loves "garlic, onion, aye and leeks" – aye was perennial lettuce, the most common European form before extensive cultivation.
The world has witnessed remarkable growth in lettuce varieties since the middle ages, a fact that seems to have delighted Lucas van Valckenborch, who used them as a symbol of summer. There are four main families today: the floppy, round variety; the long-leafed cos or romaines of caesar salad; the dark, coarse loose-leaved versions such as lollo rosso; and the crisply banal cabbage lettuces, of which icebergs are the most notorious.
To these categories we might add such offshoots as the nursery droopiness of lamb's lettuce and the tsitsa of Japan. Modern lettuces offer much less narcotic sap than their ancestors, but if you grow your own and eat it once it's bolted you may find you feel sleepy afterwards. Generally speaking, the darker and more colourful the lettuce, the better it is for you. A romaine contains around five times the vitamin C and up to 10 times the vitamin A of iceberg.
Lettuce is the best of all salad plants, bringing crimpled textures and a large surface area for dressing to slick and smear. All lettuces balance beautifully with the bite of vinegar or lemon juice, the sweet fleshiness of ripe tomato and fat from oil or avocado. The French say you should always tear lettuce rather than chop it so as not to bruise the leaves, but Harold McGee points out that this is nonsense, and that chopping is far less destructive. Until Louis XVI, lettuce tended to be cooked in France: "à la française" can mean a dish is served with braised lettuce, often little gem nowadays.
John Evelyn, you'll remember, offered sage and puritan advice in Acetaria: A Discourse of Sallets:
"By reason of its soporiferous quality, lettuce ever was, and still continues the principal Foundation of the universal Tribe of Sallets, which is to Cool and Refresh … besides the effect it has upon the Morals, Temperance and Chastity."
Lettuce has never quite shaken off this pallid joylessness. It's not as exciting as meat, spice, egg or herb. It's food for poor people (lettuce sandwich was a weepingly grim dish of the Great Depression), linked intrinsically to an ascetic, miserable veganism. Not for nothing do some dismiss it as a proverbial rabbit food. "We don't wanna sit around and eat ledduce all day," barked a chunky Virginian shock jock when Jamie Oliver turned up to teach Americans how to eat.
But another Virginian, Thomas Jefferson, grew 19 varieties of lettuce at his farm at Monticello, and the vegetable is now the US's most popular after potatoes. The average American eats 30lbs of lettuce every year, five times as much as in 1900. Almost all of that is iceberg, of course, that flavourless and watery crunch so meet and refreshing in a burger. Icebergs barely taste of anything and attract a degree of snobbery, but they're useful in wraps.
Despite a number of experiments, and perhaps to my shame, I've never been wildly impressed with cooked lettuce. I've braised it in risotto and with peas and mint and, last year, had it in a useless salmon dish at Gordon Ramsay's relaunched Petrus. I like cream of lettuce soup and Larousse has a fine-looking method for soufflé of creamed lettuce with spring onion, but on the whole I like to go raw and floppy. Do you ever cook with lettuce, and which variety do you tend to buy?
