A process of reducing the moisture in food, food dehydration concentrates flavors and allows for longer shelf life. It’s probably the oldest method of food preservation; with a history that might go something like this: One Tuesday, around 14,000 years ago, Ugg and Una absent-mindedly left a piece of fruit on a rock on a breezy, sunny day, and returned on Friday to find that it had dried out instead of growing mold. When they were still nibbling bites of the fruit the following Monday, they knew they had discovered something really useful.

Many cultures throughout history have used dehydration to preserve large amounts of food for later use. Especially in places where food is abundant in summer and hard to fi nd in winter, having stores of dried goods could be the difference between survival and starvation.

Even in the modern world, where food ships globally, and you can fi nd strawberries in Toronto in January and tomatoes in Buenos Aires in July, dehydrating food still has its place. It’s a convenient way to store food — especially large quantities — for a long period of time. It concentrates flavors, and can create chewy textures in plant-based foods that can mimic the mouthfeel of meat (hello, mushroom jerky!).And it makes food lighter and more economical to transport. While a dedicated dehydrator can make the process easier, it’s not a requirement.

Nutritional Disadvantages of Dehydrating Food

Dehydrating food can save money, energy, and time. It can concentrate flavors and prevent spoilage and waste. And it’s free and easy todo, if you’re willing and able to use sun or air-drying techniques. At this point, you might be thinking, let’s dehydrate everything! Why not?

Sugar Concentration in Dried Fruit

Well, there are a couple of downsides to dehydrating foods as well. The first is specific to fruits: the sugar concentration and glycemic index go up with a lack of moisture. This means that the sugar found in fruit can absorb more rapidly in your body and cause a spike in blood sugar, especially if you eat that dried fruit by itself.

It’s nothing personal, just math. If fruit is mostly water, and that water is removed, there’s now a lot more sugar per unit of weight. And speaking of weight, since there are four calories per gram of sugar, you are now dealing with a much more calorically dense food. Which means it’s easy to overdo it if you’re concerned about overall caloric consumption, or are sensitive to large quantities of fruit sugar. It’s way easier to snack through a one-pound bag of banana chips than it is to eat

If you’re getting your dried fruit from the store, check the label to see if there’s added sugar on top of the naturally occurring variety. Yougenerally won’t see sugar added to raisins or apple rings; more commonly, manufacturers enhance sour or tart fruit, such as cranberriesand cherries, with sugar.

Destruction of Nutrients

A second concern is there may be destruction of certain nutrients in the dehydration process. Vitamin A is destroyed by exposure to light, and vitamin C is destroyed by heat. Treating fruit with sulfite before dehydrating can mitigate these losses, but has the side effect of destroying thiamin and can also trigger allergies for some people. Blanching, or briefl y boiling vegetables prior to dehydration, can also result in some loss of vitamin C and B-complex vitamins and minerals, as all these nutrients are water-soluble.

It’s not all bad news, though. It turns out that dehydrating is comparatively one of the gentlest methods of preserving food, as it protects more nutrients than alternate methods such as canning or pickling. Can Take a While and third, dehydrating food takes much longer than eating it raw, or cooking it. Although prepping food for dehydration doesn’t take much more time than prepping it for cooking, the drying process is lengthy, depending on the drying method used and the size and amount of moisture in food pieces. Most drying methods take at least four hours, and often much more. Sun drying requires the most time. And using an electric dehydrator is quickest.

Energy Usage

And finally, certain methods of dehydration, such as freeze drying, electric drying, and oven drying, use energy, which incurs additional costs and causes environmental impact.

Whatever method you use, store dried foods in a cool, dry, dark place for maximum shelf life. Recommended storage times for dried foods range from four months to a year, depending on the ambient temperature. Because food quality is degraded by heat, the higher the temperature, the shorter the storage time. For example, most dried fruits can last for a full year at 60ºF, and just six months at 80º F. Vegetables have about half the shelf-life of fruits.