Here is a short little movie my girls made showing how to make yogurt. . . They watch a lot of cooking shows.  Here's the recipe.

Homemade Yogurt (makes 4 pints)

Supplies: 

Four 1 pint glass jars with lids

Candy Thermometer

Cooler and a blanket that will fit in the cooler

Ingredients: 

7 Cups of Milk

1/2 C instant powdered milk

1/2 c yogurt (plain or vanilla without preservatives)

Optional: 

1/2 c Sugar

1 Tsp Vanilla

Directions: 

1. MIX all ingredients EXCEPT yogurt  (milk, powdered milk, sugar, vanilla)
2. Heat to 180 degrees. (use a thermometer or look for little bubbles around the edges of the pot)
3. Pour into a bowl to cool.  Let cool until between 115 and 110 degrees.  (about an hour)
4. Measure out yogurt and let it sit on the counter to warm to room temperature.  DO NOT add it to the milk yet.  
5. When the milk mixture is between 115 and 110 degrees add the yogurt and stir until combined.  
6. Pour the milk plus yogurt mixture into the jars and put on the lids.  
7. Incubate: Put the jars into cooler, wrap a blanket around to add insulation.  Do not disturb for 6-9 hours.  Your goal is to keep the temp at about 90-100 degrees for the entire incubation time.  
8. You are done!  You did it!  Refrigerate as normal. 

  

If your yogurt did not set up - the temp when yogurt added to the milk was too hot or too cold or your yogurt starter did not contain live cultures.