Making Yogurt

Materials Needed

• Half-pint carton of milk• 500 ml beaker• Powdered milk• Heat source (Bunsen burner, hot plate, etc)• Thermometer (0-100°C)• Starter yogurt culture (any non-flavored yogurt)• Incubator• Refrigerator

Procedure

• 1) Pour the half-pint carton of milk into a beaker.

• 2) Add 11g of powdered milk to the beaker and stir. Heat to 96º C, stirring constantly. Do not boil! Keep the heat at low to medium.

• 3) Cool milk to 46º C while continuing to stir.

More Procedure

• 4) Add 5 ml of starter yogurt culture to the empty milk carton. Pour the cooled milk into the carton and staple shut. Label the carton with date and student name.

• 5) Place in an incubator at 39º C until it coagulates (6-8 hours).

• 6) Remove the carton from the incubator and cool to 10º C in a refrigerator.

What to do for incubator?

• Option 1: Buy a yogurt maker. Directions included!

• Option 2: Buy a heating pad and a cooler. Set the heating pad on low (=39ºC).

The final product

• You can add your own jam or fruit to flavor your yogurt.

• I suggest you also add at least one teaspoon of sugar to the yogurt! It is a little tart at first without it. (1 teaspoon sugar=8 oz yogurt)

• The yogurt may not taste the same as it does in the store, but nothing is perfect!