Thanks to all that replied to this.  Of special note was the observation
that the system behaves like an RC circuit.  Very nicely put, Harold.

After doing some research, which led me to finding out what a joule is
(and watt-hour, calories, erg, BTU, etc), I figured out that method 1
bellow is the best for my specific need. Explanation follows the
diagram:

 |   |      |   |
 |---|------|---|
 |   |      |   |
 |   | milk |   | 
 |   |______|   |
 |              |
 |    water     |
 |______________|
  ^^^^^^^^^^^^^  <- heat

1) heat water to the temperature I want milk to reach and then keep
water's temperature constant until milk reaches the same temperature
2) heat water to a higher temperature than I want milk to heat and then
let it cool down while milk heats up with the heat given off by water
until eventually both reach the same temperature

For my purposes, it is important that the center of the milk reaches
temperature X without any of its mass going above X, and method 1 does
just that.  With method 2, if not carefully monitored and controlled,
the mass surrounding the center of milk can raise above X before the
center reaches X.  Therefore, for simplicity sake, method 1 is better.

Another complexity that I found during my research is that the specific
heat of the milk will change as time goes by because it will solidify
(will change from milk into cheese).  This also adds the small problem
of not being able to keep stirring the milk while it heats up as I can
do with the water to maximize the heat transfer.

Thanks again.


-Mario

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