ice cream maker or ice cream freezer is a machine
used to make homemade ice cream. There are both manual and
electric types of machine.
From Wikibooks, the open-content
An ice cream maker has to do two
things; the mixture has to be cooled, and during this cooling
process, the mixture has to be constantly churned to break up ice
crystals that form and introduce some air to the mixture so that
the resultant ice cream will have a smooth, creamy texture.
Whatever the type of ice cream maker, it is possible to make ice
cream of a texture that is ready to serve straight out of the
machine. However, some recipes, especially those containing
alcohol, need to have the freezing process completed in a freezer
before the ice cream is a firm enough consistency. Once ice cream
is in the freezer, it usually needs to be taken out of the freezer
between 20 and 30 minutes before serving to soften it, partly to
make it easier to serve and eat and partly because when ice cream
is very cold, the flavour is impaired.
Some machines, such as certain
low-priced counter-top models, require that the resulting mixture
be frozen an extra four hours or more (or overnight), depending on
the recipe, in order for the ice cream to harden to a desired
These machines take the form of
an inner bowl which sits in a larger outer bowl. The inner bowl
has a handcranked mechanism which turns a paddle (sometimes called
a dasher) to stir the mixture. The outer bowl is then filled with
a mixture of salt and ice which provides the cooling power. The
addition of salt to the ice causes freezing-point depression. As
the salt melts the ice, its heat of fusion allows it to absorb
heat from the ice cream mixture, freezing the ice cream.
This type of ice cream maker is
inexpensive, but inconvenient and messy as during the process the
ice and salt mixture melts and then the user is left with a lot of
salty water to dispose of. Also, between each batch of ice cream
the ice and salt mixture has to be refilled.
There are also very small manual
models which are pint-sized bowls whose walls are filled with a
coolant. The paddle is normally combined with a plastic top. The
mixture is poured into the frozen bowl and placed in a freezer.
The paddles then are turned by hand every ten minutes or so for a
few hours until the desired consistency is reached.
There are three types of electric
ice cream machine. Each has an electric motor which drives either
the bowl or the paddle to stir the mixture. The major difference
between the three is in how the cooling is performed.
Counter-top machines use a
double-walled bowl which contains coolant between the two walls.
This is frozen in a domestic freezer for up to 24 hours before the
machine is needed. Once frozen, the bowl is put into the machine,
the mixture is added and the machine is switched on. The bowl
spins, which stirs the mixture over a stationary paddle assembly.
Twenty to thirty minutes later, the ice cream is ready. The
advantage of this type of electric machine is low cost, typically
under $100. The disadvantage of the pre-frozen bowl approach is
that only one batch can be made at a time. To make another batch,
the bowl must be frozen again. For this reason, it is usually
possible to buy extra bowls for the machine, but of course these
take up a lot of freezer space.
Small freezer-unit machines sit
inside of the freezer section of a refrigerator and operate
similar to a food processor in slow-motion. The paddles turn every
few seconds to stir the mixture enough so that large ice crystals
do not form. Some of these machines require that the electrical
cord be plugged in outside of the freezer, which can be
cumbersome. Some refrigerators made after 1982 have a built-in
ice-cream maker as an accessory or a specialized electrical plug
for use with certain freezer-unit machines. The advantage of this
approach is that no pre-freezing of the appliance is necessary.
However, some people feel that this type of machine produces a
lower-quality ice cream because of its slow-motion method.
More expensive machines dispense
with the coolant bowl and instead have their own mini-freezer
built in. When using these machines, the cooling system is
switched on about 5 minutes before the machine is needed, and then
the mixture can be added and the paddle switched on. As with
coolant-bowl machines, ice cream is ready in 20 to 30 minutes. The
huge advantage of this approach is that use of the machine
requires no pre-planning, and batch after batch of ice cream can
be made. The main disadvantages are cost, as these machines cost
upwards of $300, and size. As well as being large, these machines
usually cannot be moved without waiting 12 hours to use the
machine again as moving the unit upsets the coolant in their
freezing system. For this reason, it is normal to keep these
machines permanently on the work surface, which can be impractical
in a smaller kitchen. Because of these disadvantages, these
machines are usually only for ice cream fanatics.