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Select
Right Ventilation & Humidity
Watch humidity and
ventilation during the drying process very carefully. Humid air slows
down
evaporation. Food contains a lot of moisture and rapid dehydration is
desirable.
The higher the temperature and the lower the humidity, the more rapid
the
rate of dehydration will be. Make sure the ventilation around your oven
or in your food dryer is adequate, because moisture from the food
escapes
by evaporating into the air and trapped air soon takes on as much
moisture
as it can hold, and then drying can no longer take place.
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.
Note:
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.
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| Did You Know? |
Preservation
processes include:
* Heating to kill or denature organisms (e.g. boiling)
* Oxidation (e.g. use of sulphur dioxide)
* Toxic inhibition (e.g. smoking, use of carbon dioxide, vinegar,
alcohol etc)
* Dehydration (drying)
* Osmotic inhibition ( e.g. use of syrups)
* Low temperature inactivation (e.g. freezing)
* Ultra high water pressure (e.g. fresherized, a kind of “cold”
pasteurization, the pressure kills naturally occurring pathogens, which
cause food deterioration and affect food safety.)
* Many combinations of these methods
* Chelation
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