Dry your food with a solar food dehydrator
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[edit] Solar food drying
Solar food drying is fun, easy and free. With renewable sunshine, you can dry as much as you like, as often as you like. Solar food drying is a far more practical way to dry your garden produce than most people would think.
A good, high-performance, solar dryer is designed to harness the sun efficiently and will work amazingly well in almost any part of North America, and at most times of the year.
Using the sun to dry food may be the oldest form of food preservation, dating back thousands of years. For many prehistoric people, dried fruits, berries, grains, fish and meat were essential to surviving the cold winters. Hanging or laying food out in the open air and sunshine was the simplest method available for drying and preserving the food collected over the summer. But open-air sun drying has many limitations.
Solar drying is a big step forward over sun drying. "Solar dryer" is used to refer to a durable, enclosed, weatherproof design that takes advantage of solar energy design principles to efficiently dry food. "Sun drying" refers to simply placing food out in the open sunshine to dry.
You can learn all the latest about this exciting solar application from the new book,The Solar Food Dryer: How to make and use your own high-performance, sun-powered food dehydrator, by Eben Fodor (2006) from New Society Publishers.
Drying is an excellent method of food preservation that maintains a high level of flavor and nutrients, while providing a convenient, compact, easy-to-store supply of your favorite produce. Solar food drying is an ideal application for solar energy. Solar radiation passes through the clear glass top of a wooden dehydrator box, then the heat trapped by the box dries the food. The dehydrator also may have an absorber plate inside, which indirectly heats your food and creates a convection current of air that enters a vent at the bottom of the dryer (see illustration). The cool, fresh air that enters the vent heats up, circulates through the dryer, then exits through a vent at the top. As your food dries, moisture is carried away with the hot air. For more information see here. ALso see Solar food dehydrator related FAQ's
[edit] Why dry
Locally-grown produce -- whether from your garden or the local farmers' market -- is seasonal. The prime season begins in May and ends in October. If you want to enjoy this goodness all year long, solar food drying is your ticket to health and happiness!
[edit] How To Dehydrate Food By Solar Drying
Dryer racks
Food dryer
Dehyrator
Dried foods
Recent efforts to improve on sun drying have led to using homemade solar drying units. Using a solar drying unit also uses the sun as the heat source.
Below is a picture of a typical homemade solar food dehydrator. Fast drying is key to good food quality and to maximizing your productivity as a food preserver. Most of the work in food drying goes into the food prep: washing and slicing. The rest is easy. You can dry some foods in one day and a full load of even the wettest foods in just two days of sunshine with a good solar dryer.
[edit] Pasteurization of Certain Sun or Solar Dried Foods
Sun or solar dried fruits and vine dried beans need treatment to kill any insect and their eggs that might be on the food. Unless destroyed, the insects will eat the dried food. There are two recommended pasteurization methods:
1. Freezer Pasteurization - Seal the food in freezer-type plastic bags. Place the bags in a freezer set at 0°F or below and leave them at least 48 hours.
2. Oven Pasteurization - Place the food in a single layer on a tray or in a shallow pan. Place in an oven preheated to 160°F for 30 minutes. After either of these treatments the dried fruit is ready to be conditioned and stored.
[edit] Tips for Fast Solar food drying
Fast drying is key to good food quality and to maximizing your productivity as a food preserver. Most of the work in food drying goes into the food prep: washing and slicing. The rest is easy. You can dry some foods in one day and a full load of even the wettest foods in just two days of sunshine with a good solar dryer.
Fast drying requires three things: heat, air movement, and proper food prep. Here are my tips to fast solar drying:
Maximize solar heat input to your dryer
Start your solar drying on a day with a good sunny forecast. You need a sunny day on the first day of drying to get most of the moisture out and start the preservation process.
Clean the glass glazing with a damp cloth before each drying session to remove any dust. Dust on the glass can easily reduce your solar gain by 10% to 20%.
Get maximum solar rays by adjusting your dryer to face the sun. I usually adjust it three times: for morning sun, midday sun, and evening sun.
Optimize air flow
Airflow is necessary to remove moisture and replace moist air with dry warm air. Solar dryers rely on natural convection instead of mechanical fans to move the air. Warm air rises, so controlling the top vent on the dryer regulates air flow.
Adjust the venting on your dryer to allow maximum airflow, while also maintaining adequate drying temperatures. Drying temperature is up to you, but I like to dry at 120 to 140 degrees F because food dries faster at higher temperatures.
Proper food prep
Proper food prep will greatly speed drying. Slice all food to a uniform thickness so that each piece will dry at about the same rate. Generally, I try to keep all foods to a thickness of 1/4 inch maximum.
Cut through fruit and vegetable skins so that the flesh is exposed. Skins can greatly impede drying.
Load food so that there is a little space around each piece of food to facilitate air movement. Overloading the dryer will slow drying and will not save time.
This is all you need to get great results. If the weather gets partly cloudy on the second day, you will still get good results, even if you need to take an extra day, since your food already has most of the moisture removed and the preservation process has started. However, if your weather turns overcast or rainy, make use of the backup electric heating on the SunWorks dryer to finish off the sun's work.
