How Does an Ice Cream Maker Work?

People who live in cold climates understand that salt is a great way to melt ice on sidewalks and driveways. But the same people might not understand that salt is also a key ingredient in making things freeze!

How can this be?

We’ll look at the basic process and relate it to how an ice cream maker works. The common ice cream maker, whether hand-cranked or with an electric motor, is used to make ice cream at home rather than buy it in the grocery store. There are a few methods for using home ice cream makers but they vary only a bit from one to another.

Ground Rules

In the best of all worlds, an ice cream maker causes the mixture to harden, approaching a frozen state. Yet the paddles in the container must keep the mixture stirred to prevent ice crystals. In addition, this constant motion makes the ice cream smoother. It could freeze solid or in clumps without consistent churning/stirring.

In decades past, families would make ice cream in the backyard or the park and take it from the container almost immediately. In some cases, the family decided to pack the container tightly in ice and cover the top area with a blanket to allow the ice cream to harden just a bit. Then it could be served in almost perfect form.

The inside container is filled with the mixture and the paddles are inserted. This sits in a larger container, often wood, sometimes plastic. The space between the inside container and the larger container is filled with ice, with salt occasionally mixed in. Salt is used to change the freezing point. Salt melts the ice and this process causes some of the warmth from the ice cream mixture to be drawn out. This significantly lowers the temperature of the mixture inside the container and it hardens more rapidly.

New Technology

While many of us have experienced the cranking of ice cream when it is made manually, others have moved to a similar ice cream maker that uses an electric motor for stirring the mixture. This saves wear and tear on the elbows. (Some people may remember having to sit on the top of the ice cream maker to hold it still while Dad or an uncle made the final few turns of the hardened ice cream.)

Electric machines use a motor to drive the stirring paddles. Some chill the cream mixture in a double-bowl formation. Others are the same as the hand-cranked model, with an internal, metal container and an outer plastic or wood container. Some of the smaller, electric models can produce ice cream in half an hour or less. In the past, the manual models would produce ice cream in a period of 90 minutes to two hours, with a lot of hand-cranking in the meantime. Most of the electric units and hand crank units make larger amounts of ice cream, while electric models designed for counter-top use make smaller amounts.