How to make home made yogurt from scratch

This will be the easiest thing you have ever done.  

Yogurt is just milk fermented with certain live cultures. 

You need to have some from a previous batch, some live whey, or the easiest, a small cup of premium plain yogurt.  Whole is best without any fruit. 

I use two pots.  One fits in the other to keep from burning the milk. You can use one but use medium heat and stir constantly so it doesn't scorch.  

Sanitize everything.  Boil water and turn the other pot so the steam cleans the one the milk goes in. 

Sanitize a spoon and thermometer. 

Place the smaller pot in the larger pot where the water is boiling. Make sure the boiling water does not overflow.

Add a gallon of whole milk.

Stir the milk every once a while until it reaches 180°F. This is when your milk will start to froth. Remove from heat. 

Put the pan in your sink with cold water  until it is 100°F.

Add 3 tablespoons of your store bought yogurt, whey or cultures from your last batch. 

Put the entire pot in your oven with the oven light on. This will keep the oven at 100°F. Let it do it's thing for seven hours.

7 hours later...

That liquid on the top is whey. 

Stir up the yogurt and put it in mason jars. 

Plastic is ok too but glass is best. 

 Put it in the refrigerator overnight.

DONT FORGET TO KEEP A CUP OF YOUR NEW BATCH SO YOU CAN MAKE MORE WITHOUT BUYING IT FROM THE STORE. 

The next day, you can put your yogurt in a colander lined with cheesecloth and let the whey drain out. This will cause your yogurt to be thicker. In an hour it will be Greek yogurt. Overnight it will be yogurt cheese.

You can use yogurt cheese as a mayonnaise. 

Keep the whey. We will be making homemade katchup tomorrow.