Shaking ice cream in a bag
Also searched as: homemade ice cream with kids, ice cream without a machine, salt and ice experiment
In short: With ice cubes, salt and two bags, milk turns into ice cream in ten minutes.
Like a fridge you shake: salt makes the ice colder, and shaking keeps the ice cream fine.
- 250 ml milk, or half milk and half cream
- 2 tbsp sugar, a little vanilla sugar
- one small and one large zip-lock freezer bag
- 2 handfuls of ice cubes
- 4 tbsp coarse salt
- gloves or a tea towel
The salt brine gets very cold: do not hold it with bare hands for long.
How it’s done
Put milk and sugar in the small bag, press out the air and seal it well.
All steps as a list
- Put milk and sugar in the small bag, press out the air and seal it well.
- Put ice and salt in the big bag.
- Put the small bag inside and seal the big one.
- Wearing gloves, shake and knead hard for 5–10 minutes.
- For comparison, do a second try with ice but no salt.
What you see
With salt, the milk turns firm and creamy after a few minutes, and the big bag gets ice cold on the outside and fogs up. Without salt, the milk stays liquid.
makes the ice melt and lowers the freezing point of the resulting brine far below 0 °C. This brine draws heat out of the milk until it freezes. Shaking keeps the ice crystals small, which is why the ice cream turns creamy.
Sources · 1
- Harold McGee: On Food and Cooking (2004)