When you make a salad with lettuce, you expect it to be a green -- not brown -- side dish. Brown leaves aren't usually harmful to eat, but they sure can make a salad look unappetizing. Whether you're storing lettuce for several days or just trying to transport it to a potluck, you can keep your greens from turning brown with a few simple tricks.
If you rupture the cell walls of lettuce leaves, which can happen if you cut or bruise the leaves, they come in contact with the air. This causes a chemical reaction that turns the leaves brown. Homegrown lettuce can also turn brown on the tips out in the garden when exposed to harsh weather conditions or improper soil. The ripening chemical known as ethylene, which many fruits including bananas produce naturally, can also hasten browning of lettuce leaves.
Start with a quality head of lettuce -- avoid any that look wilted or limp. Excessive moisture is the enemy of lettuce -- but the right level of humidity leads to crisp leaves. Keep whole heads of lettuce intact. Wrap them in a lightly dampened paper towel, and then in a plastic bag or sealed storage container. Small leaves should be washed immediately and thoroughly dried. Then place them along with several paper towels in a sealable plastic bag or box. Place the wrapped lettuce in a very cold section of the refrigerator, such as a vegetable drawer. When stored, keep the lettuce away from high ethylene-producing fruits, including apples, pears and peaches. When packaged this way, lettuce can last as long as 10 days before wilting and browning.
Cut leaves are likely to brown before whole leaves. You can purchase special knives that allegedly delay browning on cut leaves, but their effect is barely any better than when lettuce is cut with traditional stainless steel knives.
You're best off tearing the leaves by hand because it follows the natural leaf veins and leads to less harmful cell rupturing, which encourages browning.
A salad transported to a potluck that's fully mixed and dressed is far more likely to wilt and turn brown than one that's mixed at the event. So instead prepare each item separately:
- Clean the lettuce, dry it and separate the leaves from the head, tearing or cutting them into bite-size pieces. Place the pieces in a large bowl and cover with plastic wrap.
- Chop up any vegetable additions, such as bell peppers, carrots and tomatoes and place into a separate container.
- Transport items that brown easily, such as avocados or apples, whole and chop at your destination -- or leave them out entirely.
- Place any croutons, nuts or dried fruit in a separate baggie or container.
- Mix the salad dressing, and bring it in a jar or tupperware shaker.
Only when you've arrived should you mix the salad ingredients. This ensures all the elements maintain their proper texture and the lettuce stays crisp and green.