Select Right Temperature

Food contains a lot of water, therefore it is very important to select right temperature and drying method. Successful drying depends upon the removal of enough moisture from the food to prevent spoilage and it must be done as fast as possible at a temperature that does not seriously affect the texture, flavor and color of the food. Drying process should never be hurried by raising the drying temperature. The optimum temperature for drying food is 140ºF. For the first part of the drying process, the air temperature can be relatively high, that is, 150 to 160 degrees F (65 to 70 degrees C), so that moisture can evaporate quickly from the food. Watch the process very carefully, and as soon as surface moisture is lost (the outside begins to feel dry), the air temperature must then be reduced to about 140 degrees F (60 degrees C). For the best results use a thermometer to check the oven temperature to make sure it stays at 140 F. Check the temperature about every half hour, because it is very important to keep the oven temperature at 140 degrees F.

If you use higher temperatures to long the food will cook instead of drying. If the food cooks on the outside and the moisture cannot escape the food may harden on the surface and the food will eventually mold. 

If the temperature is too low at the beginning, the food may undergo undesirable micro biological changes before it dries adequately. 

Keep in mind that heat is not the same in all parts of the oven or dryer and stirring the pieces of food frequently and shifting the racks in the oven or dryer are essential for uniform drying.

To speed the drying process you can increase only the air flow (not temperature).

Lighter load dries faster than a full load. Keep in mind that some food needs to be turned over occasionally for successful drying. Stirring occasionally prevent foods from sticking to the trays and also helps the food to dry evenly.

It is very important to watch whole drying process carefully, because toward the end of the drying process the food can scorch easily (each fruit and vegetable has a critical temperature above which a scorched taste develops).

Never use the broiler unit of an electric oven because the food on the top tray will dry too quickly. The best solution for oven drying is a proper model of convection oven that has a timer and controllable temperature starting at 120 degrees F.

Real Cooking

Did You Know?

It is good idea to keep the oven door open (for electric oven 5 to 6 inches, for gas oven 2 to 3 inches) during drying for ventilation. A block of wood (or something else) will help to keep the door open so that moist air can escape while the heat stays in the oven. 

If your oven do not have a fan, you can place an electric fan in front of the oven door, it will help to keep the air circulating. Be careful because this is not a safe practice for a home with small children.

In general, do not attempt to dry food on rainy days when the relative humidity is high. The drying process will take much longer than on low humidity days. Humid air blown across the food contains more water vapor than dry air, so the humid air cannot hold as much of the water being removed from the food. FREE Recipes