If you're one of those people who can't stand cilantro and think the herb tastes like soap, stop reading now. But if you love cilantro, and wish you could put it on everything, you know that it's best enjoyed fresh—which is why it's so sad when fresh leaves of cilantro gets slimy before you have a chance to use it. The trick to keeping this herb fresh for as long as possible comes down to learning how to store cilantro properly. And fortunately, it's not that hard a skill to master.
Cilantro starts to wilt when it loses moisture, so the goal of any good cilantro storage method is to keep the leaves plump and hydrated. That's why food science wiz and writer J. Kenji López-Alt at Serious Eats recommends treating cilantro like freshly cut flowers. To store, simply snip off the bottom of the cilantro stems, and remove any leaves that have already wilted. "Transfer them to a large Mason jar with an inch of water in the bottom," López-Alt writes, then, "Seal the jar with the lid (if it fits), or cover the top of the jar with an overturned plastic bag sealed with a rubber band. Store in the refrigerator." If you use this method, you should be able to keep your cilantro looking good for up to three weeks.
If your cilantro does go limp, you can attempt to revive it. The experts at Cook's Illustrated recommend soaking lackluster leaves in cold water for ten minutes to bring them back to life. As they write in Cook's Illustrated Cookbook: 2,000 Recipes from 20 Years of America's Most Trusted Food Magazine, "we found that soaking herbs in water restores the pressure of the cell contents against the cell wall, causing them to become firmer as the dehydrated cells plump up."