How do you ripen an avocado quickly?

The reliable method is a paper bag with a banana or an apple. Ripening is driven by ethylene, a natural plant hormone that fruits emit as they mature, and bananas and apples are strong ethylene producers, so sealing an unripe avocado in a paper bag with one traps the gas around it and accelerates the process, typically cutting ripening from several days to one or two. Keep it at room temperature, not the fridge, which slows ripening down, and check daily by pressing gently near the stem; it is ready when it yields slightly.

Skip the internet shortcuts that promise a ripe avocado in ten minutes. Microwaving or baking a hard avocado only softens it by cooking, producing a warm, off-textured result that tastes nothing like a properly ripened one, since real ripening involves flavor and fat changes that heat cannot fake. There is no genuine instant method for a rock-hard avocado. Once one is perfectly ripe, you flip the problem, moving it to the refrigerator halts ripening and buys you two or three more days before it turns brown and mushy.