Stretchy Mozzarella – chemical reactions

Stretchy Mozzarella – chemical reactions

Short description
Full description
Short description

Stretchy Mozzarella – chemical reactions

Type of resource:  Digital book/Video

Web address

Language: English


It takes chemistry to transform milk into mozzarella, which is called a pasta filata, or stretched paste, cheese.

Scientific concept introduced

Reactions: exploring chemical reactions between different materials.

Creative and critical thinking

Critical Thinking:
- Analysis
- Explanation

Mathematical reasoning


Scientific thinking

Drawing conclusions

Learning how to learn

Following guidelines
Turn taking in groups


Oral Language skills
Fine motor skills through preparation of food
Pre-reading skills
Collaborative skills through group Work
Safety in the kitchen

Full description

Stretchy Mozzarella – chemical reactions

Overall aims

To enable pupils to explore the chemical reaction between different materials

To develop pupils’ skills in listening and following instructions

To develop pupils’ cooking skill of mixing and stirring

To develop pupils’ skills in observing and predicting

To develop pupils’ skills in sharing and turn-taking

To develop pupils’ skills in measuring

To develop pupils’ skills in recording

Vocabulary - keywords should be understood

Bland, chewy, cooked, crunchy, flavorful, lumpy, raw, smooth, soft, sweet, texture

Expected learning outcomes (operational aims)

The child will be enabled to:

- follow instructions for making mozzarella

- explore how different ingredients react with one another

- practice stirring

- separate milk into curds and whey

- practice the skill of stirring

- make observations about how ingredients react and change

- work together in small groups

- graphically record their results

STEM skills - to which the learning unit is related to


Asking questions

Observing and making predictions


Analyzing the results involved in the process of making glue




Drawing conclusions


Hand-eye coordination

Fine-motor skills



Oral Language

Cooking skills of stirring and mixing

Following rules of safety

Group work


Teaching methodologies/activity outline

Making mozzarella from milk

Teacher Note: Do not use ultra-pasteurized milk to make cheese. Regular pasteurized milk will work fine. You can purchase cheese-making supplies online or at a bricks-and-mortar brewing supply store. Rennet, the set of enzymes used to make milk into cheese, is generally not vegetarian, but you can get vegetarian versions that will work to make mozzarella. Read the label to see how much to add per gallon of milk. Cut tablets with kitchen shears, not a knife.

1. If using calcium chloride and lipase, add both to 1/2 cup (120 ml) cool water and stir. If not using calcium chloride and lipase, put aside 1/2 cup (120 ml) water for Step 6.

2. In another small container, add the rennet to 1/4 cup (60 ml) water.

3. In a separate bowl, add the citric acid to 1/2 cup (120 ml) water.

4. Pour the milk into the large pot or pan. Add the citric acid solution from Step 3.

5. Stirring over medium-high heat, bring the milk to 90°F (32°C) and remove from the heat.

6. Add the calcium chloride/lipase solution or water from Step 1. Add the rennet solution from Step 2 and stir the mixture for 30 seconds.

7. Stop stirring, cover the pot, and let the mixture rest for 5 minutes.

8. With a knife, cut the curds in the pot into a grid and set them back on the stove, heating them to 105°F (41°C), stirring gently so the curds stay together.

9. Remove the pan from the heat and stir carefully for another 5 minutes.

10. Use the slotted spoon to move the curds out of the pot and into a microwave-safe container.

11. Microwave the curds on high for 1 minute and pour off any liquid. Use a spoon to fold them over a few times.

12. Microwave the curds for another 30 seconds and repeat until they reach 135°F (57°C).

13. Sprinkle the salt over the curds, and when the cheese is cool enough to touch, fold the curds over, stretch them, and repeat.

14. As you work the cheese, the texture should change; the cheese will feel harder to stretch and look glossy.

15. When the cheese is ready, mold it into several small balls, or one big one. Store it in the refrigerator until you eat it.


It takes chemistry to transform milk into mozzarella, which is called a pasta filata, or stretched paste, cheese.

Milk contains a unique group of proteins called caseins, and some casein molecules have tails that cling to water, keeping them suspended in milk, along with fat and other milk proteins. Heating milk and adding acid creates the right conditions for rennet, a chemical called an enzyme, to chop the tails off the caseins. Without tails, the caseins lose their love for water and clump together, trapping fat and some water to create curds.

One advantage of using rennet instead of a harsher acid like lemon juice to make cheese is that it creates a more neutral environment. This allows specific microbial cultures to be grown in cheese for extra flavor.

Assessment of learning

Pupil observation sheet

Equipment and materials to be used in learning unit (tools, ingredients etc)

- Saucepan

- Strainer or coffee filter

- Spoon

- Video

Kind of setting

Kitchen or classroom with cooking facilities (ie hot stove).

References - source

Digital Book
Liz Heinecke, Kitchen Science Lab for Kids: 52 Family Friendly Experiments from Around the House, Quarry Books, 2014


Stretchy Mozzarella – chemical reactions

1. Usefulness for STEM education - integrating content of different disciplines

Cross-curricular character of the resource 


The range of S-T-E-M subjects included 


The presentation of possibilities of including artistic activities (STEAM approach)



2. Expected learning outcomes

Consistency (links) with preschool core curriculum


Communicativeness of description


3. Methodology of teaching

Clarity, communicativeness of instructions for teachers


Meaningful learning - using practical life problems


Original idea 


The level of ease in implementing the methodology to preschool age children




The level of ease in preparing necessary ingredients, materials and equipment needed



4. Sustainability

Ecological characteristics of materials/ results


Supporting healthy eating habits 


Low ecological footprint


Possibilities of inclusion (respecting cultural diversity and food intolerances)


5. Class management

Using differentiated forms of work - individual, team work etc.


Individual work





Team work





Whole group




6. Time management


Short activity (10-15 minutes)




Medium activity (20-30 minutes)




Long activity (1 hour or more)




Very long activity (1 day or more)

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