The first is iceberg, also known as crisphead. It has a round, compact pale-green head and will last for over a week in the refrigerator because it is 90% water. Generally the mildest of the lettuces, iceberg lettuce is valued more for its crunchy texture than for its flavor. It is typically eaten cold and raw in salads, sandwiches, hamburgers, tacos, and in many other dishes. Iceberg lettuce can be very satisfying when garnished with a heavy dressing such as Buttermilk-Blue Cheese.
The second type of lettuce is romaine or cos lettuce. The heads consist of long pale-green leaves that are crisp in texture. When preparing romaine, it is best to discard the dark outer leaves as well as the darker tops of the inner leaves. The crispest, most flavorful parts of the romaine are the lighter leaves near the center. You will sometimes see these labeled as romaine hearts. Romaine pairs well with other crunchy salad ingredients such as cucumbers and onions, as well as fruit and nuts.
The third type of lettuce is the butterhead variety. It it also sometimes referred to as butter crunch lettuce. Butterhead lettuces have small, round, loosely formed heads with soft, buttery-textured leaves ranging from pale green on the outer leaves to progressively smaller pale yellow-green on the inner leaves. The flavor is sweet and succulent. Because the leaves are quite tender, they require gentle washing and handling. There are 2 main varieties of butterhead lettuce.
The fourth type of lettuce is the loose-leaf variety. This variety of lettuce does not form a compact head. The leaves on a head of loose leaf lettuce arrange themselves around a central stalk and are generally large and curly. The leaves are soft, tender, and mild in flavor. To use a whole head, you can twist the base of the lettuce to separate the leaves. Loose leaf varieties include red leaf, green leaf, Ruby, and Oakleaf.