This summer, our hill at the lake will be used in yet another ingenious way: to make ice cream for our root beer floats. I was tempted to buy the traditional ice cream maker, but there are so many choices; I quickly became overwhelmed looking at all the bells and whistles. And besides, I have all that boy power just dying to get put to use. Plus, the process of making ice cream by hand… literally…. in the can… is is a great way to introduce some lessons in science. There is the ice cream in a bag method; my boys would surely break the bag in the mixing process. So, I’ve decided to go with the ice cream in a can method.
- The first challenge is finding the can. Many recipes suggest using a coffee can, but who buys coffee in a can anymore? A better idea is to ask for an empty paint can from the paint store. You’ll need two: A quart, and a gallon.
- Ask your kids to tell you the freezing point of water — or teach them — 32 degrees F, or 0 Celcius. Then, ask them what happens when we put salt on icy sidewalks. Ask them to start thinking about why we need salt to make ice cream.
- In the small, clean can, add one cup of milk or half and half, one cup of sugar, and one teaspoon of vanilla.
- Optional: add one tablespoon of chocolate syrup — or frozen strawberries.
- Use a hammer to seal the lid tightly.
- In the larger can, combine the ice and rock salt. Use a thermometer to record the temperature of the rock and salt mixture.
- Use hammer again to seal the lid tightly.
- Take turns rolling the can down the hill, for about five minutes. This will “solidify” the ice cream.
- Explain what’s happening: the ice melts and combines with the salt. This “brine” has a lower freezing point — lower than 32 degrees.
- After five minutes of rolling, open the large can, and take the temperature of the ice. It will be colder than it was the first time.
- Open the smaller can. The colder brine was able to get the milk mixture cold enough to freeze to a solid, to create ice cream.
- You know you’re going to have to whip up another batch right now; the fun was really rolling the can down the hill.
- An instant way to eliminate the ice cream headache is to put your tongue on the roof of your mouth. Teaching a toddler how to do this is something you won’t soon forget.
Pictures to come…