Source code ?

 This is about source code of a sort.  Not computer source code, it's yogurt.  That sweet stuff, mixed with fruit in the dairy case at your grocery store is actually living bacteria.  All you need to do to make your own yogurt is to save a little (two tablespoons, 1/8 cup) and then introduce that starter to some milk.  In no time you will have cloned up a nice supply of yogurt, but you have to add your own fruit and sweetening.

First, heat up 1/2 gallon of water to about 120-130 F and then pour it into 4 old cleaned out salad dressing bottles.  Then those are put into a nice styrafoam cooler with a wire rack placed on top.  Then  heat up a little over 1 quart of milk to 185 F on the stove.  Then cool it down to 120-130 F.  Then add that little 1/8 cup of "source code" to the warm milk, mix well and pour into six half-pint jars and screw on the lids (I use canning jars but any glass jars with lids will work).  

Then put those 6 jars into the cooler on top of the wire rack

the jars in the old Omaha Steaks cooler

, put the cooler lid on tight.  Then sit tight for roughly 4 hours or so (overnight is OK) and  you should end up with 6 jars of plain yogurt.
opened a jar of active cultures, that's a canning lid on the left

  After it cools down I put it into the fridge at least overnight.

Instead of paying Dannon all that money for Activia (and sending Jamie Lee Curtis' kids to college ?), you can just buy Dannon (or Yoplait, or whichever you prefer) once and keep saving that little bit at the end for the next batch.  Also, no need to deal with all those little plastic containers.  BTW, those blue lids for the canning jars are from mayo jars (the house brand not Hellman's).

As for milk, I usually buy one with fat, normally 2%, skim will work but it has a different, less smooth texture.  Chocolate milk didn't work for me as yogurt, it didn't jell.  Strawberry pink milk made nice smelling yogurt but they don't sell that here anymore.

And yes, powdered milk will work fine, Nido is a nice milk (full fat) although fortified.  If I use powdered milk along with distilled water I only heat the milk to 120-130 F since both the powdered milk and the distilled water should be free of bacteria/yeast or whatever other little bugs that 185 F heating gets rid of.

Finally, yes, sometimes you'll lose the recipe, the yogurt gets too old or the milk wasn't sterilized well enough or ? anyway, a batch won't jell.  Just buy another container of yogurt and start again.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm