Wilted lettuce can be revived to crispness with a surprising method

The common sight of sad, limp lettuce leaves in the refrigerator often leads to them being tossed. However, these seemingly lifeless leaves are usually just dehydrated, not spoiled.

Lettuce, like most leafy greens, is about 95% water. Once harvested, the plant loses its natural water source and begins to dehydrate, causing it to lose its structure and signature crispness. This wilting occurs as the water-filled vacuoles within plant cells shrink, reducing the internal pressure that keeps the plant tissue firm.

The most widely recommended method for reviving wilted greens is to submerge them in ice-cold water for 15 to 30 minutes. This process, known as osmosis, allows the cells to rehydrate. The cold temperature also slows down the enzymes that contribute to further decay.

However, a less intuitive method, favored by some professional chefs, involves using warm water. Submerging the wilted leaves in water between 104 and 122 degrees Fahrenheit (40-50 degrees Celsius) for a similar duration can also be effective. After this warm bath, the leaves are drained, wrapped in a damp cloth or paper towel, and chilled in the refrigerator to regain their crispness. This "thermal shock" is believed to more efficiently rehydrate the cells.