When cut and left at room temperature, an avocado typically turns brown after about six hours. Ways to extend the freshness and slow down the browning process include keeping the pit intact; covering with a nonporous top; and rubbing the surface of the avocado with lemon or lime juice. Use all three methods simultaneously to keep a cut avocado fresh, with minimal discoloration, for up to two days in the refrigerator.

If you are working with avocado in a dish that will be served within a few hours, water is your ally. Avocado pieces immersed in water will stay fresh for up to four hours. For a shorter time, simply rinsing them with water helps delay browning. Save any leftover guacamole by pouring about half an inch of lukewarm water over the top of the dip, then covering and refrigerating for up to three days.