Each glass container begins with powdered milk and water mixed more concentrated than you would for milk, with a little bit of yogourt added. The yogourt then grows in the milk until the mixture is thick, or the yogourt has "set up".
Here is the heater! Just a lightbulb that my father (Heber Jones) screwed into an empty, repurposed, tin oil can and a large window is cut out of the side. The heat is reflected up, but the can on it's side is also a suitable support for the pan. Use a 40W non-eco bulb to generate just the right amount of heat for the yogourt to grow.
I first became interested in making my own yogourt because I hated all the plastic containers that were generated as waste from buying yogourt. I recently started buying skim powdered milk from Binn Inn (a local wholesale food place), refilling a bucketful, so there also isn't packaging from buying the powdered milk. (And you can reuse some yogourt from the last batch for the next!) I do it to avoid the rubbish, but it's also pretty economical money-wise, works out to be about 45 cents a serving.
Here is the recipe for the yogourt - it makes about 8 small glass jars of yogourt:
260g of skim milk powder
1.15 L warm water (1 litre plus 150 mL)
1 cup of yogourt
*The milk powder I use calls for 100g powder to 1L water to mix up regular milk. When you're making yogourt you are concentrating the milk by 2.25 times.
Mix together and pour the mixture into 8 glass jars. Place the jars in a warm water bath in a pot or pan, and place the pan onto your yogourt heater. Takes about 6 hours, or until the yogourt has set up thickly. Remove from the water bath and refrigerate.
Fresh yogourt! Once you try it, it's really easy. Go try it now!
Mix together and pour the mixture into 8 glass jars. Place the jars in a warm water bath in a pot or pan, and place the pan onto your yogourt heater. Takes about 6 hours, or until the yogourt has set up thickly. Remove from the water bath and refrigerate.
Fresh yogourt! Once you try it, it's really easy. Go try it now!
PS - I asked my parents the other day about reusing yogourt from your last batch to start the next, what happens over time. They said that in time other "bugs" get into the yogourt, and you need to buy a fresh starter from the grocery store. I asked, what did they do in the old days? Apparently they would see what would grow spontaneously, if someone had a good strain they would share it around. Strange to have to depend on the grocery store...