An ice cream maker is a device that turns and chills a central canister, allowing the custard mixture inside to become ice cream. In addition to this use, cooks can also this appliance to make sorbet, gelato, and dairy free ice creams. Many ice cream recipes are available using a wide variety of ingredients, and all of them can be made with a conventional ice cream maker.
There are three primary parts to the machine. An external drum opens so that a canister for the ice cream mix can be placed inside. A central churn is pushed into the drum, so that the mixture will be stirred. Traditionally, the canister holding the ice cream remains still, while the churn rotates around the inside, scraping down the sides and redistributing the chilled portions of the mixture. Alternately, some versions use a motor to rotate a frozen canister, while the churn stays still. Either way, as the custard is churned and chilled, it thickens, ultimately turning into ice cream.
Several techniques are used for chilling the mixture. The traditional method is ice, which is packed with rock salt to lower the freezing point, making it even colder. The ice is packed between the drum and the canister, and periodically replenished as it melts down. Home kitchen machines may also have a canister with liquid in its walls that can be frozen, so there's no need to add ice. Other ice cream makers use an electric cooling system, as is the case with the large continuous batch machines used by commercial ice cream companies.
A small hand cranked device will produce ice cream in around 20 minutes, although a team of people to crank it is highly recommended. After the ice cream is made, it is typically allowed to rest before being served. An electric machine may operate more quickly, and allows people to perform other tasks while the ice cream is being made.
To make classic rich custard style ice cream, a cook can beat five egg yolks together with 2/3 cup (about 150 g) sugar and heat the mixture over a double boiler, adding two crushed vanilla pods and 1 cup (236.5 ml) of half and half. The cook should heat the mixture until it thickens, strain it to get the vanilla pods out, and stir in 2 tablespoons (28.4 g) of butter and 1 cup (236.5 ml) of whipping cream, along with 1 tablespoon (17.7 ml) of vanilla. The custard should be allowed to cool before it is poured it into the ice cream maker, where it should be made following the manufacturer's directions. The flavor can easily be altered with the addition of inclusions like chocolate chips, nuts, fruit, and other flavorings such as mint, or rum.
To make sorbet, a cook can puree approximately 2 pounds (1 kilogram) of the fruit with 1/2 cup (118.2 ml) of citrus juice such as lemon or lime, and add a sugar syrup made from 2/3 cup (about 150 g) superfine sugar and 1 cup (236.5 ml) of water. The syrup should be heated on low until the sugar dissolves and then boiled for one minute before being allowed to cool. The sorbet mixture can be churned as directed by the manufacturer.