Ice, Cream... and Chemistry - American Chemical Society (2024)

FAQs

How to make ice cream in a bag in 5 minutes? ›

The amount of air added to ice cream is known as overrun. If the volume of ice cream is doubled by adding air, then the overrun is 100%, which is the maximum allowable amount of air that can be added to commercial ice cream. The less expensive brands usually contain more air than the premium brands.

An exothermic reaction is a chemical reaction that releases light or heat, otherwise known as energy . In this case, heat is released from molecules moving around, freezing cream into ice cream! More exothermic reactions include the burning of materials and explosions.

Icecream is a heterogeneous mixture because here solid ice (small crystals) are dispersed in a liquid (cream) medium. A heterogeneous mixture is made up of two or more than two substances that remain physically separate.

The dreaded freezer burn is formed when water in your ice cream melts and refreezes. To prevent this, the Passionate Penny Pincher suggests keeping your ice cream in a sealed bag in the freezer. It's also supposed to keep ice cream softer.

Step 1In a small resealable plastic bag, combine half-and-half, sugar, and vanilla. Push out excess air and seal. Step 2Into a large resealable plastic bag, combine ice and salt. Place small bag inside the bigger bag and shake vigorously, 7 to 10 minutes, until ice cream has hardened.

Have you ever bought something with vanilla ice cream in it (like an ice cream sandwich) and found that its edges are tinged yellow. That is because the ice cream at one point was not kept at the proper temperature.

The science behind this has to do with the way that salt lowers the freezing point of water. When you add salt to ice, it causes the ice to melt. This is because the salt dissolves in the water and creates a brine solution. This brine solution has a lower freezing point than pure water, so it causes the ice to melt.

When you add salt to the ice in the outer bag, the ice (at 0°C) is now above its freezing point – so it begins to melt. Melting requires energy, and in this case that energy comes from the flavoured milk mixture in the inner bag.

How does sugar affect the freezing point of ice cream? ›

Sugar lowers the freezing point of water, which makes frozen desserts fair game for changes in freezing point. Most desserts freeze between 29.5 to 26.6 degrees F (-1.4 to -3.0 C) depending on the concentration of sugar.

That is why ice cream isn't solid, but rather, a mixture of three states of matter: Solid ice, liquid sugar water, and air as a gas.

The two-bag method works because of the combination of salt and ice. Salt causes the ice in the bag to melt at a lower temperature than usual (if you've sprinkled salt on an icy sidewalk, you know the drill), keeping everything much colder for longer.

Take your zip-top bag and fill it with water until it is 2/3 of the way full. You can also opt for less water, but don't overfill it! You want room in the bag for the water to expand as it freezes. Put it in the freezer, ideally sort of nestled between some other things to give it a bit of shape.