Supermarket apples are often picked when not fully tree ripened. The reason is mainly to do with picking while the flesh is very firm to prevent bruising and other cosmetic damage that would eliminate it from displaying on the grocery store shelf. The home gardener and small farmers can afford to let the apples remain on the tree longer, when the flesh may become too soft for wholesale purposes. An apple that you know from the supermarket as a green apple turns out to be golden yellow and red when fully tree ripened at home. For example, Golden Delicious is not a pale green mildly sweet apple, but a genuinely light golden skinned apple with a glint of ruby red. It's one of our richest and most delicious apples. The sugars are much higher if they are fully tree ripened, but more importantly, they are more complex and rich.
Most apples are ready to pick when they separate easily from the tree and the fruit comes off when you give it a gentle lift and twist. Another indicator is the color of the seeds in the core. When apples are ripe, the seeds turn dark brown. If you're not convinced an underripe apple will taste green or starchy, while ripe apples are sweet and juicy. Overripe apples get mealy. To avoid pulling out the stem when you harvest, don't yank the apple to pick it; instead hold the apple in your hand, tilt it upward, and twist to separate it from the branch with a rotating motion.
Early ripening apples often do not store well. The late ripening varieties are best for storage.That said, all apples continue to ripen in storage and become, sweeter, though proper refrigeration slows this process. That means an apple is its most tart right off the tree. If a particular variety istoo tart for you, store it in the fridge for a couple weeks and then try it. A good keeping apple will continue to develop a more complex flavor upon storage. Some apples, such as Arkansas Black, Goldrush, Hauer Pippin and Newtwon Pippin can be kept for 8 and 10 months. Apples keep best at temperatures around 32-34 degrees, which is colder than most refrigerators are typically set. If you are going to be keeping your apples for more than a week, it is a good idea to keep them hydrated by putting a damp sponge or cloth with them in the plastic bag. Remember, moisture up, temperature down.