Dehydrating Foods: Part One
'Tis the season of bustling Farmer's Markets and busy roadside stands. This is when I get the most use out of my dehydrator. Whether I am saving the last of my herbs before the frost, or am saving space because all that I preserved earlier in the season has over-flowed my cupboard, that dehydrator comes in mighty handy. I think I've mentioned before that mine is an Excalibur that is many years old, and has withstood a great deal of wear and tear. But it's still going strong.
How is food preserved and made storable by dehydration? By removing the moisture from foods, the growth of bacteria, yeasts, and molds is inhibited. Enzyme action is slowed, but not inactivated by dehydration.
Drying foods is a slow process. Patience is absolutely necessary. If you try to accelerate the drying time by increasing the temperature of your dehydrator or oven, you can cause what is called "case hardening." Case hardening occurs when the outside of the food cooks, leaving moisture, which will later cause mold. For dehydration to preserve foods successfully, the food must dry slowly, from the inside out.
Always use fresh, fully ripe fruits and vegetables for dehydrating. Cut away any bruised or damaged parts, and slice thinly, no thicker than 1/8-1/4 inch. If the food is too thick, it will either not dry completely, causing it to mold in storage, or getting too tough to use. In addition to the condition and moisture content of the food, there are three environmental factors that you must take into consideration when dehydrating: temperature, air flow, and humidity.
Because you are trying to remove moisture from the food in order to preserve it, high humidity is counter-productive to your interests. Good air flow can cut drying time and is essential when drying high moisture-content foods, such as tomatoes. One of my first attempts at dehydrating was with tomatoes, and it was a total flop. I was using a dehydrator without a fan, and filled my trays with fresh tomatoes. Although I rotated my trays often, and had the dehydrator well ventilated, my tomatoes molded. I was so disappointed. The moral to this story is: I now use my fan-less dehydrator only for things like herbs, which have little moisture to begin with, and put all my fruits and vegetables in a dehydrator with a thermostat and fan. That fan and thermostat are absolutely necessary if you are attempting to dry foods in an area with high humidity, so keep that in mind if you are shopping for a dehydrator.
Latest Articles