Apples

Apples are the edible fruit of trees in the Malus genus (in the rose family). Commercially grown apples are from the species M. domestica which was domesticated from the wild form M. sieversii, a tree that originates in the mountains of Central Asia. Most other species of apples are small, green, and too sour to eat though they are often used in cooking.

There are a number of commercial varieties found in the supermarket including Honeycrisp, Fuji, Gala, Golden Delicious, Granny Smith, and Red Delicious. Since apples are generally not grown from seed, instead being grafted onto rootstocks, most apple varieties are genetic clones of each other. Different apple varieties may vary in their optimal storage/preservation procedures.

Optimal temperatures
Honeycrisps are best stored between 36-40°F, while Fuji, Gala, Golden Delicious, Granny Smith, and Red Delicious apples are best stored at 30-34°F. Honeycrisps are very sensitive to low temperatures and rapid cooling or cold storage can cause injury. Gala apples soften quickly and should be cooled rapidly.

Pathological disorders
Blue mold (caused by Penicillium expansum) and gray mold (caused by Botrytis cinerea) are the two most common decay-causing diseases on apples. Both of these infect wounds and so fruit injury should be avoided as much as possible. Other important procedures are cooling quickly and sanitizing with chlorine water (most tap water has chlorine in it).

Using
Since apples store and transport relatively well, they're great for giving out as standalone snacks. However, apples can also be hard to chew threw which can make them inaccessible for some folks. In addition, you may have just been given too many apples that you don't know what to do with. Luckily, there are a large number of ways apples can be cooked, prepped, and preserved to deal with these issues.

Dried apple slices
Drying apples is a great way to store apples that might otherwise go bad. The can be enjoyed as a snack all on their own or mixed with other ingredients for trail mix, granola, or as a yogurt topping. They can also be used in making desserts such as cakes. Dried apples can also be rehydrated later for usage in baking or desserts. Fresher apples will make more tasty dried apples.

Drying apples is best done with a food dehydrator, but can also be done in an oven on really low heat for a very long time. Either way the process involves coring apples and dipping the slices in an acidic solution of water and either lemon juice, vinegar, or citric acid for 10-30 minutes. This is to prevent browning. Peeling can be skipped if used for snacking or trail mix, but you may want to peel if you plan on using them for cooking later. Then the apple slices must be dried by patting with a towel. If there is too much moisture on them they could end up steaming in an oven instead of drying. This is not as much of a concern if using a food dehydrator however since the air is cycled.

Another, much less common, method of drying apples is to string up the apple slices (or put them on a stick) and air dry them over a stove or fire. Depending on the environment, this can take several days, but is the traditional way dried apples were made.

Seasonality
Apples require a cold enough hours of total cold days in the winter to set fruit. These are the fruiting seasons for apples in some of the top-producing states in California:

Apple production
The countries that produce the most apples are China, the US, Poland, Italy, and France, in that order. In the US, only 5% of apples are imported, mostly in the late season. Apples require a certain amount of cold hours in the winter in order to set fruit so states like Florida and most parts of Texas don't produce apples. Instead states like Washington (which produces around 60% of US apples), New York (~10%), Michigan (~8%), Pennsylvannia, California, and Viriginia produce the most apples.

In 2016, Washington produced 85% of all organic apples in the US. Gala, Fuji, and Honeycrisps are the most popular varieties for organic production while the most popular for conventional agricultural production are: Red Delicious, Gala, Granny Smith, Fuji, Golden Delicious, Honey Crisp, McIntosh, Rome, Cripps, Pink Lady, and Empire apples.