Excerpt from the judgement in a similar later case in Britain:
"I accept Mr. Hathaway?s evidence that the temperature settings for the Blickman and Bloomfield coffee machines were pre-set by the manufacturers and were as follows:
Blickman
Brewing temperature 86.66 C to 90 C (188 F to 194 F)
Holding temperature 86.66 C to 90 C (188 F to 194 F)
Bloomfield (up to September 2001)
Brewing temperature 78.88 C to 83.33 C (174 F to 182 F )
Holding temperature 75 C to 78.88 C (167 F to 174 F)"
So it's pretty obvious at least some of the machines have separate brewing and holding temperature settings. If not, I'm fairly confident McDonald's has enough of these things to tell the manufacturer whatever they want to do with one and get it.
The judge however wasn't having any of it, including the if it was a lower temperature it wouldn't have been as bad of a burn argument, because according to what was presented to him even the lower temperature they were asking for was still in the 3rd degree burn in 2 seconds range. However, he is of course not an expert in thermodynamics and can only go on what he is told. A model or experiment is only as good as the assumptions behind it. It doesn't sound like anyone bothered to rig up a human analog with temperature sensors, get it up to body temperature and with clothes on it actually pour the damn coffee on it.
This doesn't tell me whether they were applying a fixed heat source, say a thick metal plate, which would hold its temperature, versus a spilled liquid which would be losing its temperature rapidly in a dynamic situation which would give different results. I'm guessing the former. There's also the clothing which would also reduce the temperature before contact with the skin. Small differences, but we're talking about whether a temperature is reached in 2 seconds (you're screwed) or 10 seconds (you have time to go "FUCK!" a couple times, gather your wits, release your seat belt, and yank down your pants.
-Kevin