53Milk Shakes and Brain Freeze
Nothing beats a milk shake on a hot summer day. Its cool and
refreshing whether you suck it through a straw or spoon it into
your
mouth. But, it might also cause sphenopalatineganglioneuralgia
if
youre not careful.
As with many foods and drinks, what you call a milk shake
depends on where youre from. While most of America calls a
milk shake a milk shake, New Englanders may call it velvet
or
frappe, or even cabinet when in Rhode Island.
The basic ingredients in a milk shake are milk, ice cream,
and
flavoring, although over the years a variety of ingredients have
been
used to provide specific flavors, meet certain demands, or
minimize
costs. For example, some shakes at fast-food restaurants dont
even
contain milk or ice cream and are formulated to be inexpensive
and
quick to make.
Although the name is derived from milk, its the ice cream
that
makes a milk shake cool and refreshing. To make a shake, milk
and
flavors are added to ice cream and the mixture is whipped in a
blending
device. Ice cream already contains air, with up to half of the
volume of
ice cream made up of small air bubbles. When whipped with
milk,
even more air is incorporated to make a frothy shake.
Ice cream also contains lots of small ice crystals, which give
the
cooling sensation and also govern texture. More ice means
harder
ice cream, and low temperatures mean more ice thats why ice
cream right out of the deep freeze is hard enough to bend a
spoon.
To make a milk shake that can be sucked through a straw, ice
cream
needs to be warmed up a bit to melt some ice. Adding milk
and
whipping are sufficient to turn ice cream into a thick,
semi-fluid
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drink. To make a thicker shake, use more ice cream and less milk
so
there are more ice crystals.
In a sense, theres a continuum in thickness depending on the
amount of ice. Ice cream mix and fluid milk, with no ice
crystals,
are on the fluid end of the spectrum, whereas deep freeze
ice
cream, with most of the water in the form of ice, is on the
solid
end of the spectrum. In between, the milk shake leans toward
the
more fluid side with less ice, while soft-serve ice cream or
custard
leans toward the more solid side with more ice. A super thick
milk
shake is in between the standard milk shake and soft-serve
ice
cream.
Whats your favorite flavor of milk shake? Chocolate, straw-
berry, and vanilla are traditional favorites, but everything
from
bubble-gum grape to Cherry Garcia has been tried. Theres even
a
Krispy Kreme flavored milk shake.
One popular milk shake flavoring is malted milk, made by
adding malted milk powder to a regular flavored milk shake.
Ori-
ginally developed by the Horlicks brothers in 1873 in Racine, WI
as
an infant nutritional supplement, malted milk powder is a
combi-
nation of dried malted barley, wheat flour, and milk. Most
sources
cite a soda jerk at a Walgreens soda fountain in Chicago in 1922
as
the first person to add malted milk powder to a milk shake to
make
whats now known as the malted.
Regardless of flavor, ice-cold milk shakes can induce brain
freeze, or sphenopalatineganglioneuralgia. The deep cold of
the
milk shake, or any frozen product, causes the blood vessels in
the
roof of your mouth to constrict. This is followed by the
dilation of
the blood vessels to bring heat back into the area when the cold
is
removed. A neural signal generated by the blood vessel
dilation
causes a referred pain, meaning a pain felt somewhere other than
at
the source of the problem, in the head. A brain freeze headache
is
the result.
The exact location of the referred pain depends on where the
cold is applied in the mouth. This might explain why no two
brain
freeze headaches are exactly the same. Interestingly,
researchers
also found that brain freeze headaches are only induced in
the
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