Ice cream freezer

A domestic ice cream maker is a machine used to make small quantities of ice cream for personal consumption. Ice cream makers may prepare the mixture by employing the hand-cranking method or by employing an electric motor. The resulting preparation is often chilled through either pre-cooling the machine or by employing a machine that freezes the mixture.

An ice cream maker has to simultaneously freeze the mixture while churning it so as to aerate the mixture and keep the ice crystals small (less than 50 μm). As a result, most ice creams are ready to consume immediately. However, those containing alcohol must often be chilled further to attain a firm consistency.

Some machines, such as certain lower-priced countertop models, require the resulting mixture to be frozen for additional time after churning is complete.

Around 1832, Augustus Jackson achieved fame for creating multiple ice cream recipes and pioneering a superior ice cream preparation technique and decoration.

In 1843, Nancy Johnson of Philadelphia received the first U.S. patent for a small-scale hand-cranked ice cream freezer. The ice cream freezer was a pewter cylinder.

Dubbed the "Queen of Ices", English culinary entrepreneur Agnes Marshall was granted a patent for an ice cream machine that could freeze a pint of ice cream in five minutes.

These machines ice and salt mixture must be replenished to make a new batch of ice cream.

Some small manual units comprise a bowl with coolant filled hollow walls. These have a volume of approximately one pint (500ml). The paddle is often built into a plastic top. The mixture is poured into the frozen bowl and placed in a freezer. The paddles are hand-turned every ten minutes or so for a few hours until reaching the desired consistency and flavor. Nancy Johnson invented the first hand-cranked model in 1843. She then sold the patent to William Young, who marketed the machine as the "Johnson Patent Ice-Cream Freezer."

There are four types of electric ice cream machines. Each has an electric motor that drives the bowl or the paddle to stir the mixture. The major difference between the four is how the cooling is performed.

Counter-top machines use a double-walled bowl with a solution between the walls (typically distilled water and urea) that freezes below 32°F or 0°C. In a domestic freezer, this requires up to 24 hours before the machine is ready. Once frozen, the bowl is put into the machine, the mixture is added and the machine started. The paddles rotate, stirring the mixture as it gradually freezes through contact with the frozen bowl. After twenty to thirty minutes, the solution between the double walls thaws, and the ice cream freezes. This type of machine has the advantage of being relatively inexpensive; however, a pre-frozen bowl makes only one batch at a time. The bowl must be refrozen to make another batch. Multi-batches require extra bowls for the machine, which require extra freezer space.

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Wikipedia