How does milk turn into cheese?

How does milk turn into cheese?

Much of the food we eat started out as something else. Bread comes from wheat, ketchup comes from tomatoes and cheese and butter come from milk. The process by which these foods are created is often a mystery to children, and by experimenting with making their own versions of these foods, they can begin to understand and have a greater appreciation for the fuel they are putting into their bodies.

 

Suggested Materials

Skim milk
Vinegar
Lemon juice
Coffee filters or cheesecloth
Clear 9 – 16 ounce plastic cups (4 cups per team)
Rubber bands
Plastic spoons
Measuring cups
Eyedroppers

 

Preparation
Make some cheese ahead of time so you are familiar with the process. See Make it Happen instructions.

 

For this activity, teams will each need 2 empty cups, 1 rubber band, 1 coffee filter or small piece of cheesecloth and a spoon. Prepare small cups of lemon juice and vinegar for each team (just a couple of teaspoons per cup).

 

1
MAKE IT
Matter
Opening Discussion
Ask your students to name as many different foods as they can that are made with milk. How do they think milk is turned into those foods? If cheese is not listed, you should mention it and ask kids to name all of the different kinds of cheese they know of. How are some of these cheeses different from each other (flavor, color, hard or soft, etc.)?

 

The Challenge
Can you make your own cheese?

 

2
MAKE IT
Happen
Doing the Activity
You may want to demonstrate this process to your students before having them attempt it.
Divide your class into teams of 2 or 3.
Measure ¼ cup of skim milk into one of the plastic cups.
If using eyedroppers (recommended), add a few drops of lemon juice to the milk. Do you notice anything happening? Keep adding drops until you see lots of clumping. If you are using spoons, add 1 spoonful of lemon juice and observe what happens (1 spoonful should be enough).
Pull a coffee filter or a piece of cheesecloth over an empty cup, then wrap a rubber band around the filter and the cup to keep the filter in place. Pour the milk/lemon mixture slowly through the filter into the cup.
Once most of the liquid has dripped into the cup below, remove the rubber band and carefully take the filter off of the top of the cup without spilling what’s on the filter. Very gently bunch the filter up and squeeze into the cup any liquid that is still inside the bunched-up filter, sort of like gently squeezing a sponge.
Open the filter back up and examine what is inside. What do you notice? Does it remind you of anything? Take a taste—what does it taste like?

3
MAKE IT
Click
Let’s Talk About It
After every team has made some cheese, stop your students and bring them together to share their observations with each other. What did they notice? How did the cheese taste? This discussion should last no more than a few minutes.

 

4
MAKE IT
Better
Build On What They Talked About
Have each team try making cheese with vinegar. Does it take more or less vinegar than it did lemon juice to make cheese? How does this cheese taste?

 

 

Suggestions
Explain that the liquid that filters through into the cup in the cheese activity is called whey. The cheese is also known as curds.
Try making cheese out of any other juices you can think of. More acidic juices will make the best cheeses.

 

 

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