How Is Yogurt Made?

Ingredients in Yogurt

Yogurt is milk that has been thickened through the introduction of certain bacteria. It is a tart food that is enjoyed the world over. Making yogurt requires few ingredients but takes great care and concentration, since it needs to be cooked at very specific temperatures.

Heat and Thicken Milk

First take an amount of milk equal to the amount of yogurt you want to make. You can start with cow milk, sheep milk or goat milk. Heat the milk to 200 degrees Fahrenheit for at least 10 minutes. It can be heated longer (up to 30 minutes) for a thicker yogurt. Immediately following this, rapidly cool the milk to 112 degrees.

Add Bacteria

After cooling the milk, add yogurt starter, which includes the two following bacteria: Streptococcus thermophilus and Lactobacillus bulgaricus. Other bacteria can be added in as well to create certain types of yogurt. Once the bacteria is added, incubated the mixture at 100 degrees Fahrenheit for a minimum of four hours. During this time, the bacteria devour the sugars in the milk and release lactic acid, which thickens the milk and gives it the tart flavor unique to yogurt. The longer the milk is incubated, the more tart the yogurt will be when it is finished.

Cool and Store

After incubating, the yogurt must be cooled in a refrigerator or similar environment. This will help the yogurt to set and the flavor to settle throughout the yogurt. The yogurt can then be kept refrigerated before spoiling for up to 10 days.