Ingredient of the Week, September 1: Lettuce
Lettuce is a member of the sunflower family.
Darker Green lettuce leaves are more nutritious than lighter green leaves.
Americans eat about 30 pounds of lettuce every year. That’s about five times more than what we ate in the early 1900s.
In the United States, lettuce is the second most popular fresh vegetable.
Almost all lettuce is packed right in the field.
About 25% of all iceberg lettuce is made into fresh cut salads.
It is eaten either raw, notably in salads, sandwiches, hamburgers, tacos, and many other dishes, or cooked, as in Chinese cuisine in which the stem becomes just as important as the leaf. Both the English name and the Latin name of the genus are ultimately derived from lac, the Latin word for “milk”, referring to the plant’s milky juice. Mild in flavour, it has been described over the centuries as a cooling counterbalance to other ingredients in a salad
The earliest depiction of lettuce is in the carvings at the temple of Senusret I at Karnak, where he offers milk to the god Min, to whom the lettuce was sacred. Lettuce was considered an aphrodisiac food in Ancient Egypt, and appears as such in The Contendings of Horus and Seth. Later, Ancient Greek physicians believed lettuce could act as a sleep-inducing agent. The Romans cultivated it, and it eventually made its way to the Papal Court at Avignon, France. Christopher Columbus introduced lettuce to the New World.
Types of Lettuce
There are six commonly recognised Cultivar Groups of lettuce which are ordered here by head formation and leaf structure; there are hundreds of cultivars of lettuce selected for leaf shape and colour, as well as extended field and shelf life, within each of these Cultivar Groups:
Butterhead forms loose heads. Its leaves have a buttery texture. Butterhead cultivars are most popular in Europe. Popular varieties include Boston, Bibb, Buttercrunch, and Tom Thumb.
Chinese lettuce types generally have long, sword-shaped, non-head-forming leaves, with a bitter and robust flavour unlike Western types, for use in stir-fried dishes and stews. Chinese lettuce cultivars are divided into “stem-use” types (called celtuce in English), and “leaf-use” types such as youmaicai
Crisphead, also called Iceberg, forms tight, dense heads that resemble cabbage. They are generally the mildest of the lettuces, valued more for their crunchy texture than for flavour. Cultivars of iceberg lettuce are the most familiar lettuces in the USA. Bruce Church founder of Fresh Express, was responsible for popularizing the idea of shipping lettuce across the US continent from Salinas, California, to the spots on the East coast. Using ice they carefully covered the heads of lettuce and shipped them year around and all the way as far as Maine, as the train pulled into each stop, folks would call out excitedly, "The icebergs are coming, the icebergs are coming!" The name stuck. Before that people had to depend on what they could grow locally and preserve from the gardens.
Looseleaf has tender, delicate, and mildly flavoured leaves. This group includes oak leaf and lollo rosso (Red Leaf) lettuces.
Romaine , also called Cos, grows in a long head of sturdy leaves with a firm rib down the center. Unlike most lettuces, it is tolerant of heat.
Summer Crisp, also called Batavian, forms moderately dense heads with a crunchy texture. This type is intermediate between iceberg and looseleaf types.
Some lettuces (especially iceberg) have been specifically bred to remove the bitterness from their leaves. These lettuces have high water content and so are less "nutritionally dense" than are the more bitter lettuces and those with darker leaves. While all lettuces contain antioxidants and vitamin K, romaine and looseleaf lettuce contain five to six times the vitamin C and five to ten times the vitamin A of iceberg. Romaine and butterhead lettuce are good sources of folate. Lettuce naturally absorbs and concentrates lithium. Lettuce is a low calorie food and is a source of vitamin A and folic acid. Lactucarium (or “Lettuce Opium”) is a mild opiate-like substance that is contained in all types of lettuce. Both the Romans and Egyptians took advantage of this property by eating lettuce at the end of a meal to induce sleepMany people are under the impression that iceberg lettuce contains no nutrients making it a waste of time to eat it and a waste of money to buy it. While it is true that iceberg lettuce is mostly water, it also contains protein, vitamins, minerals and fiber. One cup of this classic salad favorite delivers a significant dose of vitamins K – a nutrient commonly found deficient in the modern diet. Iceberg lettuce is also a good source for vitamin A which is essential for eyesight health.
Selection and Storage
Lettuce is a delicate vegetable and great care should be taken when selecting and storing. Most lettuce is showcased on ice or in refrigeration. When selecting your leaves, be sure that they are fresh and crisp, with no signs of wilting, slim, or dark spots or edges. Remember when selecting your lettuce that the darker outer leaves are the most nutritious.
Lettuce tends to keep well in plastic bags in the crisper section of the refrigerator. Iceberg lettuce keeps the best, lasting around two weeks, while Romaine, ten days, and butterheads types and endives lasts approximately four days. The very delicate greens don't last very long, so it's best to buy only as much as you need at one time and use immediately.
Salad greens should not be stored near fruits that produce ethylene gases (like apples) as this will increase brown spots on the lettuce leaves and increase spoilage. Greens that are bought in bunches should be checked for insects. Those leaves that have roots should be placed in a glass of water with a bag over the leaves and then placed in the refrigerator.
Generally lettuce is eaten raw, so consider removing any browned, slimy, or wilted leaves. For all lettuce types, you should thoroughly wash and 'dry' the leaves to remove any dirt or lingering insects. If you eat lettuce often, it's wise to invest in a salad spinner. Simply rinse the leaves and place in the spinner to remove the excess water.
In addition to their most common use in salads, you can also braise, steam, sautè and even grill certain lettuce varieties to create a wonderful and different taste treat. Try halving a head of radicchio or romaine lengthwise, and brush on some extra virgin olive oil, and grill until they soften and just begin to brown-absolutely delicious.
What's your favorite type of lettuce? Do you eat it in salads or on sandwiches?