CORVALLIS, Ore. - Perfectly ripe pears are a luscious treat. But how many times have your pears sat on your counter, then stayed rock hard, got gritty or rotted without getting sweetly ripe?
Unlike apples, most pear varieties do not ripen nicely while still on the tree. Pears that are allowed to become too mature or to ripen on the tree develop a coarse, mealy texture and often have core breakdown.
Whether you grow pears at home, or buy them in the store, it is sometimes challenging to know when to pick them, then how long to ripen them to perfection. And how do you tell when a pear is ready to eat?
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, says pears are tricky, but not really difficult, to ripen just right.
Pears picked when slightly immature will ripen with better quality than pears that are over mature when picked. To tell if a pear is mature, a general rule of thumb is that, while still on the tree, most mature, ready to ripen pears will usually detach when "tilted" to a horizontal position from their usual vertical hanging position. Bosc pears always are difficult to separate from the spur.
"Unlike apples, which are ready to eat from the day they are picked, pears must go through a series of changes before they can deliver their full splendor," explained Sugar. "Pears do not ripen on the tree to our liking. If allowed to tree-ripen, pears typically ripen from the inside out, so that the center is mushy by the time the outside flesh is ready."
"Commercial pears are harvested when they are 'mature,' he continued. "In pear language, that means they are picked when they have reached the point where they will ripen to good quality, sometimes with a little help, but definitely OFF the tree.
"So the frequently heard notion that pears are picked when they are still hard and green as a convenience for enduring the long truck ride to market misses the point," Sugar quipped.
Once commercial pears are picked, growers cool them down to about 30 degrees F. They don't freeze at this temperature, because the fruit sugar acts like an antifreeze.
"The colder the pears are, the longer they'll stay in good condition," said Sugar. "In fact, they actually need to be cooled in order to ripen properly."
Bartlett pears need to be cooled only for a day or two, and winter pears such as Anjou, Bosc and Comice require 2 to 6 weeks for optimal effect, he said.
"Without this chilling process, a mature picked pear will just sit and sit and eventually decompose without ever ripening," explained Sugar.
The pears sold in the grocery store or delivered by companies such as Harry and David are mature and have already received their postharvest chilling. They are ready to ripen, according to Sugar.
"Pear ripening must be closely watched," he warned. "There is a relatively narrow window between 'too hard' and 'too soft' where the perfect pear texture lies."
Sugar recommends ripening pears at 65 to 75 degrees F for the following times: Bartlett, 4 to 5 days, Bosc and Comice, 5 to 7 days; and Anjou, 7 to 10 days. The longer the time the pears have spent in cold storage, the shorter the time to ripen them, he said.
"As ripening begins, pears produce ethylene gas, a ripening hormone, inside the fruit," explained Sugar. "This speeds the ripening along. The ripening time gets shorter as the time since harvest passes."
Pear lovers can "kick start" the pear ripening process by putting freshly bought or newly harvested 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 quickly begin producing their own.
How do you tell when a pear is ripened to perfection?
"Hold the pear gently but firmly in the palm of your hand, as a baseball pitcher might hold the ball while studying signs from the catcher," recommended Sugar. "Apply the thumb of that same hand to the pear flesh just below the point where the stem joins the fruit. 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."
And what is the best way to eat a perfectly ripe pear?
"After years of study, scientists have found that a really juicy pear is best eaten while naked, in the bathtub, so that you needn't be concerned about the abundant juice streaming down your chin," he laughed.
For more information about the timing of picking and storing various varieties of pears, refer to OSU Extension Service's publication, "Picking and Storing Apples and Pears," (FS 147) online. Or call 1-800-561-6719 to purchase a printed copy.
To learn how to identify those pears in your garden or farmer's market, visit the Pears USA website.