Temperature vs Yogurt Science Fair Projects

Temperature

Temperature impacts chemical reactions in food. It usually acts as a catalyst or as a retardant.

Objectives/Goals

The objective was to identify how the temperature of the milk influences the time it takes for the milk to turn into yogurt.

My goal was to solve my mother's problem in identifying the optimal temperature and time to convert milk into fresh, firm, and tangy yogurt.

Methods/Materials

Materials: 1 thermometer, 12 x 2/3 of a cup of 1% milk, 12 tablespoons cultured yogurt, 4 heat resistance cups, an oven, 12 labels, Measuring Cup

Procedure: 1. Pre-heat the oven to 80F. 2. Using the measuring cup, pour 1% milk into the cup until it is filled 2/3rd. Then transfer the contents of the measuring cup into a microwavable safe bowl. 3. Then microwave the milk till it boils. 4. Repeat step 2 and step 3 for 3 more bowls. 5. Cool the boiled milk in the first cup to 120F, transfer one tablespoon of cultured yogurt into the milk and put the cup into the oven. 6. Repeat steps 5 for the remaining three cups, each time cooling the milk by ten degrees less than the previous cup at the time of adding the cultured yogurt. 7. Place the cups one by one into the oven with the oven light on, thereby maintaining an ambient temperature of 80F. 8. Based on my pre-test experiment I would check the status of the milk in the cups after, say about 6 hours. Then every 15 minutes after that. 9. After a cup has been turned into yogurt I would record it on my data table.

Results

I conducted my experiment at four different temperature points (120F, 110F, 100F and 90F) and carried out 3 trials at each point.

With 120F as the setting temperature, it took an average of 5:04:20 hours for the milk to turn into yogurt. At 110F it took 4:43:00 hours, at 100F it took 4:11:00 hours, and at 90F it took 4:48:20 hours to turn into yogurt.

Conclusions/Discussion

My research guided me to conduct the experiments with the temperature of the milk in the range of 70F - 118F. The ambient temperature was maintained at 80F during the process of curdling the milk into yogurt.

My conclusion is that the optimal temperature for the milk to turn into yogurt is at 100F. My experiment yielded no inconsistent data in relation to my hypothesis.

I was thus able to identify the optimal temperature of 100F to create fresh, tangy yogurt with a firm. 3rd party contributor