As long as they are kept at room temperature, tomatoes picked at the mature green stage will finish ripening in supermarkets and after you purchase them. Within a few days, they will soften slightly, turn red and—most important of all—develop their full flavor and aroma.

To avoid interrupting this process, place the tomatoes on a counter or in a shallow bowl at room temperature until they are ready to eat.

DO NOT REFRIGERATE THEM.

When tomatoes are chilled below 55° F, the ripening comes to a halt and the flavor never develops.

To speed up the process, keep tomatoes in a brown paper bag or closed container to trap the ethylene gas that helps them ripen. Adding an ethylene-emitting apple or pear to the container can also hasten ripening. Store the tomatoes in a single layer and with the stem ends up, to avoid bruising the delicate "shoulders."

Once they are fully ripened, tomatoes can be held at room temperature or refrigerated for several days. When you’re ready to use them, bring the tomatoes back to room temperature for fullest flavor.