Why do lettuce turn brown

But removing the air is exactly the opposite of what lettuce needs. Lettuce actually needs a good amount of airflow, in addition to a bit of moisture, in order to stay crisp. That's why restaurants store their lettuce in special perforated bins that allow for air circulation while it's held in the fridge.

Removing the air does help prevent oxidation, which is what causes lettuce to turn brown but has nothing to do with lettuce staying crisp. In any case, oxidation isn't something you should have to worry about as long as you buy fresh lettuce and use it within a few days. Trim off the end of the stem and separate the leaves. Fill up the sink or a very large bowl with cold water and submerge the leaves.

Gently swish the leaves around in the water. Any grit will sink to the bottom of the sink. Remove the clean lettuce , or empty the bowl and repeat this step for especially dirty lettuce. Now you're going to want to dry the lettuce. The best way to do this is in a salad spinner. But don't cram the leaves into it. Cut them in half or smaller so that you don't bruise them trying to squeeze them in.

Salad-spin until all the water has drained away. The leaves will still be slightly damp—that's what you want. Take the basket out of the salad spinner and cover the leaves with damp paper towels. Transfer the basket to the fridge. 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:. 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.

In other words, the damaged fruit or vegetable is trying to protect itself. The argument is that historically damage was caused by insects and fungi and that at the first sign of such damage the enzymes would swing into action to ward off further destruction. The problem is that nobody has clearly demonstrated that the brown pigments really do have antifungal or insecticidal properties.

But there certainly is some interesting chemistry there. Enter your keywords. Sign-Up Here. What to read next Why does plastic stay wet in the dishwasher whereas glass comes out dry? Is it true that the Beatles wrote a song about LSD? Is it true that you cannot eat polar bear liver?