1/2gallon(about 2 ltr or 2 quarts or 8 cups) Milk(Fat)
1/4cupYogurt as starter(Starter yogurt can be from your previous batch or you can buy Plain Yogurt from the grocery store.)
Bring Milk to a boil on the stovetop(use heavy bottomed pot) or microwave. I uaully turn off my stove when it comes to boil but If you have a candy thermometer, bring milk to approx 180 degrees Fahrenheit.
Allow Milk to cool to slightly warmer than luke warm (approx 115 degrees F on a candy thermometer).
Do not add starter yogurt into hot milk or yogurt bacteria will die and yogurt will not set.
Add Starter Yogurt to the Milk and blend together with a hand blender or whisk.
Keep your pot in a warm area of your house to get great result.
If it is cool in your house, preheat oven to 180 degrees F and switch oven OFF. Make sure that oven is just warm enough and not hot. Sometimes, I just turn on the light in the oven and with the heat of light, yogurt comes out nice(Try and you will sure love the idea!). So basically you need warm environment to make yogurt.
Place container with milk into warm oven(if using oven) and set timer for 3 1/2 hours.
After 3 1/2 hours, remove yogurt from oven and store in refrigerator. Do not keep longer than 4 to 5 hours...unless you want soury yogurt.