The bottom line: Apples don't ripen nor improve in quality at home after they're picked
You may have seen on another website that apples will
ripen after being picked. This leads many consumers to
the (false) belief that if they have unripe apples at home,
they can let them ripen on the counter or in a cool place. This is actually pretty bad advice!
If you want the detailed answer with links to
references, click here. For just the summary, read on below!
What is "ripe"?
We use the term "ripe" to define when an a fruit or vegetable is at
it's best quality for eating. For an apple that means:
- Sweetness (sugar content)
- Appearance (bright, unblemished skin)
- Firmness, crispness, lack of mealiness
- Flavor, including soluble solids, titratable acidity and flavor
- Freedom from defects such as bruising, decay, stem or blossom-end
cracks, bitter pit, scald, internal browning, shrivel or watercore,
bright skin color intensity and uniformity
The bottom line
Apples aren't like bananas or avocados, which can be picked
substantially unripe and then left on a kitchen counter to ripe and
produce a good quality. While it is technically accurate to say that
some varieties of apples can continue to ripen after being picked, in
practice in a consumer's home, this generally is not true.
- First, the apples must reach a certain, specific level of
maturity to be able to continue to ripe under appropriate storage
conditions. Dr. Sherif at Virginia Tech tells us you must “pick the
fruit for storage at starch index 3-3.5 (e.g. show a clear core and dark
flesh in the starch iodine test).
Fruits picked before starch index 3 are usually immature and will never
approach the optimal sweetness level in the storage.”
very few consumers are able to perform this chemical test and accurately
assess the apples they have purchased.
- Next, the optimal storage conditions that produce successful
post-harvest ripening are both nuanced and specific to each apple
variety. The conditions that work for one apple don't for another. A
consumer would have to check the research for the specific variety of
apple he wants to ripen to achieve success.
- The storage conditions require controlling the temperature,
humidity and oxygen levels in the storage area precisely, something few
consumers are equipped to do.
- Finally, even under ideal storage conditions, some attributes
of apple quality still decline, even as sugar or flavor may improve.
Crispness is almost always at its peak at the moment of being harvested,
and is mostly likely to decline thereafter.
What does this mean for you at home?
- Keep your apples cool - between 30 and 40 degrees F.
- Better still, use a vegetable/fruit drawer in the refrigerator
and set the humidity level of the drawer to high.
- Keep in mind that not all apple varieties store well. Softer
summer varieties, like Gala and Delicious will not store as well or long
as later, firmer varieties like Fuji or Yates.
Apple growers work hard to harvest their apples close to peak
ripeness if the apples are being sold direct to consumers and
(generally) slightly before peak ripeness if they will go into storage
or if there is likely to be a lag time before they reach the consumer.
Leave the harvesting, ripening and storage to the apple orchard
professionals! ! Unlike stone fruits, apples are available all year-round
at most grocery stores. Buy enough apples to last only a few weeks, keep them
cold and buy more when you run low! That way you will always have apples at
their peak quality!
What this means to a consumer is this: the apples you buy should
be eaten promptly, proper storage may help maintain their quality as
purchased but will not improve it.
this page for how to properly store apples at home.
How to know when apples are ripe:
- Days from bloom: The most accurate method is to count the number of days since the tree bloomed in the Spring. Each variety of apple has a specific number of days to reach it's optimum ripeness. Of course, that can vary, based on weather conditions, but it's pretty accurate.
But if you do know know or remember the date the trees bloomed, here are the other ways to tell when to harvest the apples:
- Color. Color, both on the outside and and the flesh, is a useful indication of maturity. Depending on the variety, apples may be yellow, red, green or combinations of these colors at harvest. When the green has almost completely given way to yellow, a yellow variety is mature. With red blush or striped apples, the area where there is no red color usually changes from green to yellowish at maturity.
Some of the newer red strains are challenging, because they are red all over long before they are sweet and mature. In these, the change in the color of the flesh goes from greenish to white when they are ripe. Red Delicious spur-types apples are odd in that the greenish tint may take months in storage to disappear, but they are fine to eat before that!
- Ease of separation. Unless the orchardist has used a "stop-drop" spray, that causes the apples to stay on the tree, mature apples are separate easily from the tree with a, twist it upward with a rotating motion.
- Seeds: Cut a sample apple horizontally and look at the seeds. Usually, the seeds become brown the fruit is ripe. That's more true with later ripening varieties, like Fuji. With early season apple varieties, like Gala, , they may be ready to eat before the seeds turn brown.
- Fruit drop. When a few good, healthy apples drop to the ground, the apples on the tree are nearly mature. (rotten, buggy or diseased apples can drop at any time)
- Softness and flavor. The taste test never fails! When an apple becomes slightly softer and tastes sweet and juicy, it is mature. Some varieties, such as Delicious, become sweeter in storage; but that's different from ripening.
- The Iodine starch test. An apple is cut horizontally through the core and sprayed
with a mild iodine solution. Since the iodine turns the cells containing starch
dark, unripe apples turn dark, ripe apples remain white.
Penn State has a page that has more information about the iodine apple ripeness test.
Typical apple harvest dates
For more information, see "Predicting
Harvest Date Windows for Apples" by G. D. Blanpied and K. J.
Silsby, Information Bulletin 221, Cornell Cooperative Extension
Harvest tables. Finally, Maturity dates, that is, the usual date that a variety ripens in a given geographic area is usually know by a state's apple association, local county extension offices, university extension offices, and the orchards themselves. Below are tables of typical harvest dates for apple varieties in some of the common apple growing states: