Making Yoghurt, dahi(दही), or curd at home

I decided to make yoghurt at home because the yoghurt sold in grocery stores in United States is very different from the yoghurt that I grew up eating at home in India. The grocery store yoghurt in US tends to be pretty bland and homogenized, sometimes thickeners are added to prevent separation of the liquid. Yoghurt made at home tends to be tastier and tangier, I am guessing higher amount of lactic acid, but I don't know.

Ingredients:

• 2 Cups of Whole Milk [I used Horizon milk, although any other brand would work. I would recommend using non-homogenized whole milk if you can find one, Strauss is a good brand. Raw milk would also be a good option, although it is expensive.]
• 2 teaspoons of Yoghurt [I bought 2% Fage Greek Yoghurt, which is probably one of the best commercially available yoghurt and has no additives in it].

Recipe:

• Bring milk to a boil in a pan, I used a stainless steel pot but any pot should suffice. 
• Let it cool to the point that you can tolerate the temperature when you dip your finger in the milk. For the more scientifically inclined who own a thermometer, the temperature needs to be around 115 Fahrenheit or 45 Celsius.  
• Add the two teaspoons of yoghurt and mix it with the milk.
• Keep in a warm place. I used the inside of an oven where the pilot light keeps it warm. During the summer, one can leave it outside but if you have an oven with a pilot light, then that is perfect. 
• After six hours or so, the yoghurt is ready. You can leave it longer up to 12 hours, it will just taste tangier. 
• Refrigerate and consume in two to three days. 
• Set a small amount and use it to make another batch. 

I will let you know if something unusual happens to my tummy.

Update: Nothing unusual happened to my stomach!