A quality orchard harvests only mature peaches fruit that has attained full growth and development on the tree before being picked. When mature, peaches have reached their full sugar content. Peaches that are picked too early will never ripen properly and will instead become flabby and remain tasteless.
When you get your peaches home, sort by ripeness. Use the ripest peaches first and refrigerate those you do not plan to use quickly. Contrary to popular opinion, squeezing is not a good way to determine ripeness.
Instead, look at the background color. A yellowish undercolor, especially around the stem area, is the best indicator of ripeness. The amount of red blush is not a good indicator.
Also, look for peaches with good fragrance, a well-defined crease, and a plump, round shape.
To ripen peaches further, spread fruit out on a counter or table at room temperature, not in direct sunlight. Check often, since peaches can ripen quickly, even within several hours. Fruit also can be placed in a loosely closed paper bag at room temperature out of direct sunlight. Add an apple to speed up the process even more. This method works well for firm peaches, but check bag frequently, since mature fruit can spoil if not removed soon enough.