The most traditional way to dry dates is to leave them out in the sun for a prolonged period of time. Though this method is the most straightforward, it also tends to be somewhat inconsistent — the results depend on the specific weather conditions, as well as the size and moisture of the fruit. Using a professional food dehydrator is usually the best way to ensure standard results. People who do not want to invest in one of these appliances can sometimes get similar results by slow-drying dates in a warm oven. An important part of the process is finding a method that works for you, then experimenting until you get just the right results.
People who live in date-growing regions have dried the fruit using only sunlight for centuries. In most cases, simply setting the dates outside on a tray for a prolonged period of time — usually several days — will cause them to shrivel and dry. Slicing them in half and removing the tough central pit often speeds the process.
If you're using this method, it's usually a good idea to dry dates under some sort of screen or protective shield to prevent contamination by birds or insects. A number of farms and food manufacturers sell drying screens, but fancy is not always necessary. Even setting the fruits on an enclosed porch or breezeway is usually sufficient, so long as they are still getting direct sunlight.
Dates tend to grow in hot, almost desert-like climates where the sun shines intensely for most of the day. If you live in a cooler or moister place, sunlight drying might not be as successful. At the very least, you may find yourself constantly moving the fruit to the warmest places.
Using a Food Dehydrator
A professional food dehydrator is often the fastest way to dry dates, though it can also be the most expensive. Commercial dehydrators are often very large, sometimes the size of an entire room; home-use models are typically much smaller, and can usually fit on a countertop. They work by controlling the atmosphere and air quality, artificially creating a very arid environment. At the same time, they mechanically suck moisture out of the drying chamber, often dehydrating dates and other foods in a number of hours.
The Warm Oven Approach
Buying a food dehydrator is often very expensive, and unless you are planning to dry a lot of things, it may not be a good choice for you. Instead, you can try putting the dates in a warm oven. Heat it to about 150°F (about 66°C), and arrange the fruit on a baking sheet lined with parchment paper to prevent sticking.
The fruit should be left to dry for about a day. It is usually a good idea to shut the oven’s power off intermittently, as the idea is not to cook the dates but rather to dehydrate them. Additionally, it's best to not leave an oven on long stretches of time. Check on the dates periodically, and turn them every few hours to make sure that all sides are exposed to the heat evenly.
Vitamins and Other Additives
Some dried fruit experts recommend coating dates in a concentrated vitamin C mixture in order to help them keep an attractive appearance after drying. The vitamin helps improve the elasticity of the fruit’s skin, and can lead to a shinier, more appealing dried fruit. Vitamin additives may also help speed the dehydration process by wicking moisture from the inside out.
The easiest way to add vitamin C is to soak the fruit in a mixture of vitamin C powder, which is commonly sold in health food stores, and water. Breaking open a few oil-based vitamin capsules may also work.
General Tips and Tricks
It is always important to carefully select the dates you will use in drying. They should be fully ripe, but should not show any signs of spoilage. Thoroughly washing and drying all fruits before you begin will reduce the chance of contaminants.
Paying attention to the pit is also important. Dates can be dried whole quite successfully, but the process is often a lot faster if the thick inner pit has been removed. Most food processing facilities have machines that will automatically pit the fruit, but you can achieve similar results at home with a paring knife and a bit of patience.