Around here, if I’m lucky, can get a 6oz container of organic low fat yogurt for 80c. That’s about 1.33/ounce. With an investment of $2.99 for a half gallon of organic fat free milk, 3/4c of powdered milk, some 1/2pint canning jars, and some time, I’ve got 9 x 8oz containers of delicious low fat, organic, yogurt. Figuring the cost of electricity, gas, my time, and ingredients, this probably costs about 10c/ounce. No thickeners – but really thick yogurt, no preservatives, and tastes better than anything available in the shops.
Basic recipe is: 1/2 gallon of yogurt heated to about 160-190 degrees F, don’t let it boil. hold it until you see there’s less in the pot than you started. Cool to about 125F. remove 4oz and mix with 6oz of starter (buy one container of that organic yogurt, or use some from the last batch) and add to pot. put in jars and keep warm for about 4 hours. I use a dehydrator. a yogurt maker works. Or just wrap in a warm towel in an insulated container.