Cilantro, a flavorful herb which grows from coriander seeds, is a classic ingredient in Asian, Caribbean and Latin cuisine. Though very inexpensive in the summer months, fresh cilantro has an annoying tendency to turn brown and wither within a matter of days. It doesn't have to be that way. With the skillful application of boiling water, you can make cilantro last a lot longer.
Fill a large soup or stock pot with water and place over medium-high heat. When the water boils, add 1 tbsp, of salt. Don't add salt before the water boils or it can pit the surface of your pot. Adding a lid helps speed up the boiling process.
Fill a large bowl with water and add enough ice to make an equal ice-water mix. This ensures the water will be cold enough. Set the bowl aside, but keep it within easy reach of your stove-top.
Remove any rubber bands or string holding the cilantro bunches together. Drop the cilantro into the boiling water and cook for no more than 30 seconds, or until the color turns slightly brighter green. Boiling water releases the chlorophyll in the leaves of green plants.
Remove the cilantro from the boiling water using a spider or strainer with a handle. Immediately submerge the strainer in the ice water. This stops the cooking process and sets the green color of the cilantro.
Allow the cilantro to sit in the ice water until it is cool to the touch. Then, remove it and lay it out on paper towels to dry. Once it is dry, transfer it to a zip-lock bag and place in your refrigerator. Use it within seven days.
You can use this method, known to cooks as "blanching and shocking," to preserve pretty much any fresh herb.
Don't use cilantro that is slimy or has a strong flavor. This indicates spoilage.