I have been making this for 2 years now. All you need is a thermos, dry milk, Water and 1/4 cup of fresh Yogurt for your first starter. 

Thick Yogurt Recipe

4 cups of warm water (110 deg to 115 degrees F) temperature is very important (to warm it kills the starter to cold it doesn’t work either) 

2 1/3 cups instant nonfat dry milk

1/4 cup fresh, unflavored yogurt (this is your starter you can use your homemade later as a starter as long as it’s not over 5 days old) Organic is best but regular works too. Reach for the one on the back of the shelf with the newest date. Fresh is very important. Yes, you can use flavored but all your recipe will be flavored slightly. Make sure the yogurt is active bacteria, those sweet kids yogurt crap won’t work

Combine water and dry milk in a medium-sized bowl and mix thoroughly. Stir in the yogurt or starter. Incubate using any method you like. But I do this and it is quite reliable.

Thermos method. 

Once starter has been stirred into the lukewarm milk, pour it into a wide-mouth thermos, put on the lid, and let it sit 4-6 hours before refrigerating. I wrap in a bath towel to retain more heat. The temperature is controlled for you. Do not disturb. if you disturb it it will separate and look like cottage cheese. it’s ok to eat but it look gross. You can use pure yogurt culture I find it at health food stores but I don’t like it as well. It takes longer. 

When you go to check it take the lid off slowly and tilt it until it looks thick, if not put it back on and wait another hour or so. 

The yogurt will keep 8 days under refrigeration or you can freeze it.

Make new within 5 days with your homemade yogurt as your starter. 

YOu can put yogurt in a mason jar or colander lined with a coffee filter and it will drain the whey off. Then you will have a more greek style yogurt. Thick! or Yogurt Cream Cheese some call it. I use this for dips and sour cream replacement.