Although flour is the traditional thickening agent in
most cooking, cornstarch, also known as cornflour, is a fine,
powdery flour ground from the endosperm, or white heart, of the corn kernel.
People often wonder what the difference is between cornstarch and flour. Both
are starches, but cornstarch is pure starch, while flour contains gluten. The gluten reduces the thickening power of flour,
so lacking gluten, cornstarch has
twice the thickening power of
flour. Sauces thickened with cornstarch will be clear, rather than opaque, as with
flour-based sauces, and it doesn't cause lumps like flour.
How To Cook With
What are the advantages of using corn starch
rather than flour? Corn starch has
twice the "thickening power" of flour,
so it's necessary to use only half as much. Example:
If recipe calls for 1/4 cup of flour, use just 2
tablespoons corn starch. Corn starch thickens with a satiny smoothness
and glossy appearance. It adds no taste of its own
to mask the flavor of foods.
Recipes thickened with
corn starch have a brighter, more translucent appearance
than those thickened with flour. Corn starch also
blends more easily with liquids than flour
because it doesn't absorb liquid until it's cooked.
Cooking with corn starch is easy when you follow
a few simple guidelines. Gradually stir cold liquids
into corn starch until completely smooth, cook over medium-low heat.
Cooking over high heat can cause lumping, but avoid
stirring too vigorously because it may break
down and thin out.. Stir gently during while it
thickens, the starch granules will have swelled
to their full capacity in about 1 minute.
Using Cornstarch As A Thickener
Always mix a
slurry of cornstarch and a small amount (1/4 cup) of cold
liquid (water, stock, wine, etc.) until smooth, then add this mixture to the food
that you want thickened. Do not mix with liquids that are acid such as citrus juice or apple juice
it's thickening power is cut in half.
Do not boil a cornstarch thickened
sauce or it will thin out.
As as rule, I use 1 tablespoon of cornstarch to
thicken every 2 cups of liquid to a medium consistency. Cornstarch mixed
a little cold liquid, is stirred into the hot food during the final stage of cooking,
and it must be cooked to 203°F (95°C) before thickening begins. At that
point, it usually thickens fairly quickly and the sauce turns from opaque to
transparent, but sauces will thin if cooked too long, boiled or stirred too
If recipe calls
for this much flour
Use this much
||1/2 tablespoon (1
|1/4 cup (4
|1/3 cup (5-1/3
plus 2 teaspoons
|½ cup (8
||¼ cup (4
Are There Any Problems With Using Cornstarch?
Corn starch mixtures that don't thicken at
all, or thicken and then thin out during
cooling are disappointing. One or more of the following
may have caused the problem.
Too Little Liquid: If there is not enough liquid
(water, milk, juice) in the mixture, the corn starch
granules will not fully swell and remain thickened
when the mixture cools. Adding a little more liquid
(not more corn starch) is likely to solve the problem.
Too Much Sugar: A higher proportion of sugar
than liquid (water, milk, juice) in a mixture can
interfere with the swelling of the corn starch granules
and prevent thickening during cooking and/or cause
thinning during cooling. Adding more liquid (not
more corn starch) will often solve the problem.
Too Much Fat: An excessively high proportion
of fat or egg yolks in a mixture can interfere with
the swelling of the corn starch granules and prevent
thickening during cooking and/or cause thinning
during cooling. Adding more liquid (not more corn
starch) will usually solve the problem.
Too Much Acid: Acid ingredients such as lemon
juice, lime juice or vinegar will reduce the thickening
ability of the starch or prevent the mixture from
thickening. Increase the starch level slightly or
stir acid ingredients in after cooking.
Too Much Stirring: Excessive or rough stirring
with a wire whisk or even a spoon may break the
starch cells and cause the mixture to thin out.
Excessive Cooking: Simmering or boiling a corn
starch thickened mixture for an extended period
of time may cause the starch cells to rupture and
the mixture to thin.
Freezing: Freezing corn-starch thickened mixtures
will rupture the starch cells and cause the mixture
to thin out.
Cornstarch Thickens Sauces
When added to cooking foods, the heat causes the starch to bind the water molecules
and the individual starch granules
absorb liquid and swell. By the time the mixture nears boiling, the starch
granules will have grown to about ten times their size at room temperature.
At temperatures above 205°F, however, the
large starch granules start to shrink and as these swollen granules deflate, the sauce becomes thinner,
so do not let cornstarch
thickened sauces boil.
Uses For Cornstarch
often used in Oriental recipes because it results in a lighter, more clear gravy with a glossy sheen.
Besides thickening, cornstarch helps to prevent
eggs from curdling—certainly helpful in making custards,
flans,cheesecakes, quiche and other egg dishes.
It also causes heat to be transmitted more evenly
throughout the dish, and can be used to make a glaze.
Cornstarch can be used to "flour" pieces of meat for added crispiness
when browning. It is the best choice for thickening dairy-based sauces,
and it is also used in making custards, gravies and other