What is blanching and why is it a must?
Blanching is the scalding of vegetables in boiling water or steam. Blanching slows or stops the action of enzymes. Up until harvest time, enzymes cause vegetables to grow and mature. If vegetables are not blanched, or blanching is not long enough, the enzymes continue to be active during frozen storage causing off-colors, off-flavors and toughening.
If you spend the time growing the vegetables,
pulling weeds, picking and preparing for the freezer,
the blanching time may be regarded as a pain - but it’s
necessary if you want fresh garden flavor later.
Blanching time is crucial and varies with the
vegetable and size of the pieces to be frozen.
Under-blanching speeds up the activity of enzymes and is
worse than no blanching. Over-blanching causes loss of
flavor, color, vitamins and minerals.
The most convenient way to blanch vegetables is in a
large kettle of boiling water. Allow one gallon of water
per pound of vegetables. Bring the water to boil and
lower vegetables into the water, allowing the water to
continue boiling. Cover and start counting the blanching
time. I like to use the side burner on my outdoor gas
grill for this task. It keeps the heat and steam outside
and my kitchen cool.
As soon as blanching is complete, cool the
vegetables quickly and thoroughly to stop the cooking
process. To cool, drain the vegetables in a strainer,
then plunge the vegetables into a container of ice
water. Cool vegetables for the same amount of time as
they are blanched.
Drain thoroughly and freeze.
Karma Metzgar, C.F.C.S. Northwest
Regional Director, University of Missouri Extension
Last update: Tuesday, May 05, 2009