Ice Cream in a Can
With a couple of coffee cans and just a few ingredients, you can make your own ice cream. Kids will love this "magic" recipe that turns a liquid solution into cold and creamy ice cream. Plus while you are rolling the can back and forth to make the ice cream you can work in a quick science lesson. Discuss the changing states of matter, chemical reactions, and the properties of ice and salt while working for your dessert.
On their own, each ingredient would not stay isolated in a smooth, continuous form. In order for these four ingredients to turn into ice cream, they all must be frozen and whipped simultaneously and then kept cold so that the ingredients don't glom together.
Salt is added to the ice because salt lowers the freezing point of water, making the melted ice/salt colder than the original ice. This extra-cold ice/salt mixture surrounds the ice cream can freeze the cream inside to create your ice cream treat.
There are actually two opposing chemical reactions happening at the same time. As you roll the can back and forth, the ice/salt mixture in the larger can (a solid) turns into a liquid (melted ice). When ice absorbs energy, it changes the phase of water from a solid to a liquid. The ice absorbs energy from the ice cream ingredients and also from your hands as you roll the can. Conversely, the liquid ingredients inside (milk, cream) are turning into a solid (ice cream) as the molecules in the liquid slow down and eventually freeze in place.
- Ice Cream
- 1 1/2 cups whole milk
- 1/3 cup Imperial Sugar Extra Fine Granulated Sugar
- 1 cup heavy whipping cream
- 12 cups crushed ice
- 2 cups rock salt
- 3 pound tin coffee can
- 1 pound tin coffee can
- duct tape
- rubber bands, clear plastic wrap
- optional - toppings such as chocolate chips, m&ms, etc.
NOTE: For this recipe to work, the cans need to be aluminum and it can be tough to find coffee in a true tin or aluminum can anymore. Most coffee cans are now made of plastic or cardboard. If you aren't having any luck on the coffee aisle, you can try the canned fruit and vegetable aisle.
- Mix milk, sugar and cream in the smaller can.
- Seal can with lid and secure with duct tape.
- Place the small can inside the larger can and surround with about 6 cups of crushed ice and 1 cup of rock salt.
- Attach lid to the larger can (if you have one). If not, you can use several layers of plastic wrap. Secure the wrap with a couple rubber bands and then wrap tightly with duct tape.
- Grab a friend and roll the can on the ground back and forth to each other for about 15 minutes. (We suggest you do this over some newspapers or a towel just in case there are any leaks.)
- Remove the small can from the larger one. Discard melted ice and salt mixture.
- Open the small can and stir the ice cream. Be sure to scrape the ice cream from the sides.
- Place the lid on the top and secure with duct tape and place back in larger can.
- Surround small can with remaining 6 cups of ice and 1 cup of salt.
- Secure top of large can with lid, plastic wrap, rubber bands and duct tape.
- Roll back and forth with a friend again for another 10 minutes.
- Open and enjoy immediately.
- If you want to make flavored ice-cream, use chocolate or strawberry whole milk instead.
- Not all types of salt work the same. The larger the salt crystals, the more time it takes to dissolve. This keeps it colder, longer. You could make several batches of ice cream experimenting with table salt, kosher salt and rock salt to see how much more or less time it takes to make the ice cream.
Fun Fact: Ice cream is made up of four ingredients....
- Ice crystals - Ice is created when the water in the milk and cream begins to freeze, making the solution more solid.
- Fat - The milkfat adds richness, density, and smoothness as well as stabilizes the base mix.
- Sugar - Sugar adds sweetness, texture, and body. Sugar also lowers the freezing point so that the ice cream does not freeze rock solid.
- Air - While it may be invisible, it's very important to the ice cream mixture. The tiny air cells trapped in the mixture determine the final consistency of the ice cream. Less infused air makes for a denser, richer ice cream.