Break free from plastic - yogurt edition

I want to try to make my own yogurt. Here in SF, I can get Strauss milk in returnable glass bottles, thereby reducing my personal plastic consumption. I would factor in the energy that I would personally use in my home to make this yogurt, but I feel like that would be minimal compared with the overall life cycle of a plastic container of yogurt.

I met a woman at an SF Green Film Festival event who gave me this recipe. It sounds very easy, and I am going to try it out!

Here is the yogurt recipe. The overall idea is to make sure that the milk is the right temperature. Too cold and the bacteria won't grow, too hot and it will kill the bacteria. In my experience, too hot is far more of an issue. If you have a warm place other than your oven (on top of a heating vent in your house?) it doesn't need to be done in the oven. It's just finding a way to keep it warm for the 8 hours.

Ingredients: 

1 gallon milk
3 TB from 1 container yogurt (once you start, you can use last week's yogurt)

Heat milk to a boil, turn off immediately. - Allow to cool (usually takes around 1 hour) until you can hold your pinky finger in the milk for 10 seconds (it shouldn't be painful). - Stir in the yogurt - Divide into glass jars (I use big pickle jars, etc; make sure they're clean first) - Put in oven for 8 hours or overnight with pilot light on. If it's not warm in your oven, turn the oven on low until it heats up and then turn off (you can do this throughout the 8 hours, but in my experience, it doesn't need to be done a lot). You want the oven to be around 112 degrees, but it isn't an exact science. - After 8 hours, check that the yogurt has formed. If you leave longer, it will become more sour (just depends on how you like it). You can now move to the fridge!

To make greek yogurt, strain the yogurt in cheese cloth for 1 hour - 2 hours... the longer you strain the thicker it will be.