CENTRAL POINT, Ore. - Perfectly ripe pears are a luscious treat. But often, pears go straight from rock hard to gritty or rotted, completely missing the sweet, ripe stage.
Unlike apples, most pear varieties do not ripen nicely while still on the tree. If they become too mature or ripen on the tree, they can develop a coarse, gritty texture and the core can break down.
"Pears are tricky but not really difficult to ripen just right," said David Sugar, who has spent most of his career studying fruit physiology at Oregon State University's Southern Oregon Research and Extension Center in Central Point.
Pears develop the best quality when they are picked "mature" but have barely begun to soften toward the "ripe" eating stage.
"Commercial pears are harvested when they are capable of ripening to good quality, but the actual ripening takes place off the tree," Sugar said.
A mature pear on the tree will snap briskly and cleanly off the branch when tilted to a horizontal position from its vertical hanging position. Bosc pears, however, can be difficult to separate from the branch spur on which they grow. Bartlett pears will begin turning yellow as they mature, but this is not so with other common pears like Comice, Anjou, or Bosc.
"Pears must go through a series of changes after harvest before they can deliver their full splendor," Sugar explained. "If allowed to tree-ripen, pears typically ripen from the inside out, so that the center may be over-ripe by the time the outside flesh is ready."
When commercial pears are picked, growers cool them to about 30 degrees. They don't freeze at this temperature, because the fruit sugar acts like antifreeze. "The colder the pears are, the longer they'll stay in good condition," Sugar said. "In fact, they need to be cooled to ripen properly."
Bartlett pears need to be cooled only for a day or two, while winter pears such as Anjou, Bosc and Comice require two to six weeks at cold temperatures for optimal effect, he said.
"Without this chilling process, a mature-picked pear may sit and decompose without ever ripening," he said.
Pears sold in the grocery store were picked when mature and have already received their postharvest chilling, so they are ready to ripen. But their ripening must be closely watched, Sugar warns.
He recommends ripening pears at 65 to 75 degrees for the following times: Bartlett, four to five days; Bosc and Comice, five to seven days; and Anjou, seven to10 days. In late fall and winter, ripening time gradually decreases. As pears soften toward perfection, the sweet pear aroma intensifies.
"As ripening begins, pears produce ethylene gas, a ripening hormone, inside the fruit," explained Sugar. This speeds ripening and aroma development. Pear lovers can "kick start" the process by putting freshly bought pears in a paper bag with a ripe banana or an apple, both of which give off copious quantities of ethylene gas. The bag keeps the gas near the pears, which soak it up and are stimulated to begin producing their own. If you don't want a pear to begin ripening right away, keep it in the refrigerator, until you want it to ripen.
How do you tell when a pear is ripened to perfection?
Hold it gently but firmly in the palm of your hand and press your thumb just below the point where the stem joins the fruit, Sugar advised. When the flesh beneath your thumb yields evenly to gentle pressure, it is time to eat your pear. If you have to push more than slightly, it is not ready yet.