Thursday, November 29, 2007

Drying Methods

Dehydrator drying produces the best quality dried products, so it’s not surprising that it’s also the most popular drying method. Dehydrator drying also gives you greater flexibility than other methods because it does not depend on dry, sunny days or take over your oven. A variety of electric dehydrators are available for purchase. A dehydrator should have a heat source, a thermostat, and some method of air circulation. If you buy a dehydrator, follow the directions that come with it.

Buying a Dehydrator

Before you buy a new or used food dehydrator, check to see that it has all these features:

Instruction manual.

Thermostatically controlled temperature dial with settings between 130° and 150°F.

(If you plan to dry meat jerky in your dehydrator, the dehydrator must be capable of maintaining a temperature of 145°. Contact the extension educator in your county for instructions on how to safely prepare meat jerky.)

Fan or blower to distribute warm air evenly.

Shelves made of stainless steel or food-grade plastic. (Galvanized screening is not food-safe.)

Easy loading and unloading features.

Outside cabinets made of hard plastic, aluminum, or steel. The highest quality dehydrator has double-wall construction with insulating material sand wiched between the walls to reduce the amount of heat lost during use.

Enclosed heating element.

Appropriate number of trays for your use. Most food dryers come with 4 to 10 food trays.

Source of replacement parts.

Sun Drying

Sun drying works best when the temperature is in the 90s, the humidity is low, and air pollution levels are low. A major advantage to sun drying is its low cost. Drying trays, netting to protect against bugs, and food to dry are your only investments.

Sun drying makes you dependent on the weather, however. If it is sunny one day and cloudy the next, you will have to finish drying by another method. That’s because spoilage can occur while the drying food still has enough moisture for microbial growth. Also, you should bring the food inside on cool nights. Another disadvantage is time. What dries in 6 to 8 hours in an electric dehydrator may take 2 to 4 days in the sun.

Solar Drying

Solar drying is like sun drying, only better. The sun’s rays collect in a solar box so that, compared with sun drying, drying temperature is higher and drying time is shorter. The shorter drying time gives microorganisms less chance to cause spoilage.

If you do not want to buy or build a solar box, you can use the back window ledge of an automobile where the sun shines through. Crack the windows slightly to allow air flow so temperatures do not get too hot. Cover the trays with netting to keep bugs out.

Oven Drying

You can use your oven to dry small amounts of food at one time. You’ll have little or no investment in equipment and you won’t have to depend on the weather.

Although oven drying produces a safe, generally tasty product, don’t expect top quality. Oven-dried food is more brittle and usually darker and less flavorful than food dried in a dehydrator. Another disadvantage of oven drying is its energy cost. Oven drying takes two or three times longer than drying in a dehydrator.

Before drying in an oven, test the oven temperature with an oven thermometer for about 1 hour. Prop open the oven door as you would when actually drying fruit. The oven should maintain a temperature of 130° to 150°F.

If the oven cannot maintain a temperature in this range, you will not have high-quality dried food. If the oven is too hot, your food will begin to cook instead of dry. If it is too cool, your food may not dry fast enough and spoil instead.

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