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Introduction to food drying-Part 2




NECESSARY FACTORS
In general, when drying at home, heat and moving air must be combined to 
accomplish the goal. 
You must have:
1) heat adequate to extract moisture, but moderate enough so that it 
doesn’t cook the material
2) currents of air dry enough to absorb the released moisture and carry 
it off

These conditions can occur: 
· outdoors  - naturally or with constructions which intensify the sun’s 
effect and maximize air flow 
· indoors - in electric food dryers or conventional ovens.
 
DIFFERENT WAYS TO DRY FOODS

OUTDOOR METHODS:
I - Sun and Air
Most food-drying experts agree that this method is only possible in the 
most sun-drenched regions with prolonged low humidity (e.g. 
Mediterranean, southern California) - if you do not live in an area with 
such a climate you may want to consider the other methods.
· prepare and pre-treat foods according to individual instructions
· spread prepared food on food-drying trays, be sure to protect with 
covering, place in sunlit area where air can circulate underneath the 
food - stir the food periodically during the day to allow for even drying
· expose food to open air and sun but not full sun lest the food 
“case-harden” i.e., cook the outside to form a crust that prevents the 
inside from drying well
· bring indoors before dew falls and return to direct sun the next 
morning
· test for dryness after it has finished cooling at the end of the second 
day - suggested testing techniques follow

II - Solar Dryer
Those who live in wetter, cooler regions: take heart. There are ways in 
which to dry foods using the sun.  The Solar Survival Food Dehydrator, 
trademarked by Leandre and Gretchen Poisson is designed for climates 
which are not ideal for open-air sun drying.  Through the use of a 
particular design which maximizes solar exposure and air circulation, and 
a fiberglass-reinforced plastic sheet glazing material called Sunlite 
(also trademarked), this dryer is suitable for cooler, wetter climates. 
It is easy to build and many of the materials required are inexpensively 
bought or even found for free. For more information see “Resources.”

INDOOR METHODS:
I - Electric Dryers
There are different types of electric food dryers on the market. 
Generally speaking, they can dry food rather quickly - often taking only 
12 hours to complete the task.  Since electric food dryers are all 
different, it is best to consult manufacturer’s instructions for specific 
drying procedures.

II - Using an Oven
A conventional oven can be quite effective in drying foods.  It does take 
somewhat longer than drying with an electric dryer but the expense of 
buying a special appliance is avoided.
Rules of Thumb:
· shield the food from the broiling element with a cookie sheet if 
necessary 
· leave the oven door ajar to allow for air circulation, unless your oven 
is vented (i.e., such as most gas ovens)
· maintain temperature of 60 C or 140 F - monitor with thermometer if 
necessary
· keep batches small