I'm Sandra Lee for a night

In my tireless efforts to give the kid memorable lunches, I wanted to give her some special caramel dip for her apples.  I ventured into the deepest, darkest bowels of the corpus of internet urban cooking legends ... the potentially (as in potential energy) explosive transformation of sweetened condensed milk into caramel.

sweetened condensed milk + heat ------> caramel

This transformation is filled with challenges: search, finding authority, chemistry, processed foods, momblogger stories and visions of Sandra Lee obliterated all over her chiffon peach-decorated kitchen.  Irresistible.

Too tired to plow through the billion or so anecdotes, I did read two statements with great frequency:
boil the can - it doesn't explode, and
boil the can - it does explode

I chucked a can of generic sweetened condensed milk into boiling water COVERED BY ONE INCH, and covered the pot with a 3 pound cast iron lid and let it simmer for 3 hours.  Fearfully, I peeked once in a while to insure the level of water never went below the surface of the can.  This instruction is repeated as if it were the unpublished 11th commandment.  No one knows what happens if that level drops below the top of the can.  But, I think if it does, Nader is elected President of the United States (and Sandra Lee gets in a serious kitchen accident).  

During the 3 hours, the can bulged a bit.  Not good.  After 3 hours, I cautiously took the can and let it rest in the kitchen sink overnight covered with the several pound cast iron dome.  The next morning, I opened it and scooped out some heavenly caramel for my daughter's dip.  

I would never do this again if my life depended on it - and I won't hesitate to run my silly Firedome to 1100°F.  This is dangerous.  I feel lucky there was no accident last night.

Oh, and my daughter?  She likes the Marzetti caramel dip way better.  This transformation is one processed food to another, so, there's not one iota of virtue doing it.  I don't pull the phd chemist credential often, but as a "technically qualified person," this shit's dangerous.  If you must make this, pop open the can and cook it in a double boiler.  You'll dirty a bunch of pans, make caramel, and you'll feel like Sandra Lee.