Home Made Ice Cream

Homemade Ice Cream in a Plastic Bag

Objectives:

a. To become aware of the use of Chemistry in food preparation, particularly, in ice cream.

b. To be able to understand colligative properties of mixtures, particularly, freezing point depression and its role in ice cream manufacturing.

c. To be able to mix and test various solute and solvent properties in order to form a desired mixture/product.

Materials/Ingredients:

1 quart size Ziploc

1 gallon size Ziploc

Ice

Rock salt

Milk

Vanilla Extract

Chocolate Milk

Sugar

Oreo

Procedure:

Mix all the ingredients in a 1 quart plastic bag, seal and place it on another 1 quart plastic bag. Make sure to keep the containers air tight. Place the mixture in a gallon size bag filled with ice drizzled around with salt. Always squeeze the air out of the bag. Wrap a towel around the bag then shake it for around 7-8 minutes. This should freeze your mixture which will be good enough for serving.

When making ice cream, the temperature around the ice cream mixture needs to be lower than 32 F (approximately 0 degrees Celsius) in order for the mixture to freeze. Salt mixed with ice creates a brine solution that has a temperature lower than 32 F. When you add salt to the ice water, you lower the melting temperature of the ice down to 0 F or so. The brine is so cold that it easily freezes the ice cream mixture.