How can I determine ripeness of an unknown pear on my property?
Answer: There are several indicators of ripeness or impending ripeness, including the following:1) The abscission “scar” on the stem breaks cleanly when you push up and away on the fruit. This is a spot on the stem that is bigger than the rest of the stem and usually shows a thin but clear line around the stem. This is where the fruit is attached to the spur on the limb, and when the fruit is “physiologically” ripe, it will break cleanly away from that spur right at the abscission scar, leaving a full stem with a little knob at the top. “Physiologically ripe” for pome fruit (pears, apples, quinces) means that the seeds are mature, and the fruit continue to ripen after it is picked. It does not mean that it will taste super ripe or sweet, just that the seeds are ripe and that the fruit will continue to ripen off the tree.2) The seeds are brown and hard and difficult to cut with a knife.3) The flesh will give just a little to thumb pressure near the stem.4) There is no starchy flavor or astringency. You’ll probably have to compare ripe and unripe fruits to see this, but there is actually a starch test. However, since this is an unknown variety, we can’t say with too much accuracy how to interpret the test. Here is information on the starch test from the University of Kentucky:”Starch-iodine Testing: As fruit mature, starch is converted to soluble sugars. Iodine turns starch black; therefore, an iodine solution can be used to determine the amount of starch remaining in the fruit. A solution of 10 grams of potassium iodide and 2.5 grams of iodine in 1 liter of water should be used. During mixing and use of this solution, make sure the area is well ventilated?iodine fumes are toxic. This solution should be stored in a plastic or glass container as it is corrosive to metals. Providing the container is well stoppered, the solution will keep for long periods of time. Fruit should be cut in half through the equator and the cut surface dipped or sprayed with the iodine solution from a plastic spray bottle. The starch patterns will develop in approximately 1 minute. As fruit mature, starch clears from the core first, followed by the cortex. These patterns will be slightly different for each variety. The starch index at which fruit should be harvested depends on the intended length of storage. As a guide, fruit destined for storage should be harvested at a starch-iodine index of 4 to 5, whereas fruit for immediate sale should be harvested at an index of 6 to 7. As with any indicator of fruit maturity, the starch-iodine index should be used in combination with other maturity tests.”5) Testing soluble solids with a refractometer. Again, since we don’t know the variety, this test would be somewhat useless this year, but if you have a refractometer already, you could begin to take readings on sequential days and compare the readings to your own taste test, write it down somewhere in a record book and you will have begun to provide a guideline for future harvests.6) Taste. This isn’t quite as easy as it sounds with European-type pears because so many of them reach their highest sugars and flavors after being “cured” off the tree. In fact, some of the old varieties with grit cells, like Keiffer, can barely be eaten when they’re ready to come off the tree but must be cured before the grit cells disappear. 7) Number of drops around the tree. Unless there’s just been a big windstorm, you can guess that fruit is ripening just by the rate of dropped fruit around the base of the tree. Obvious, perhaps, but this is still useful because some fruits just don’t look ripe or, like Keiffer, don’t “feel” ripe because of the grit cells. So if you see a bunch of drops, but the fruit is still hard and gritty, don’t be fooled. This fruit is likely ripe and just needs curing on your table top.For more information on all aspects of pear production, consult the ATTRA publication Pears: Organic Production, available at https://attra.ncat.org/attra-pub/summaries/summary.php?pub=7.