J. Clarke wrote:
Chris Friesen wrote:

On the other hand, McDonanlds has served 10 billion cups of coffee
and she is one of very few that had a problem. Typically that
proportion suggests the problem lies with the user not the provider.

You could turn the argument around and say that all other coffee
providers serve it at a lower temperature, so the fact that McD's is
the exception shows that they may be doing something unexpected.

If in fact all other coffee providers served it at the lower temperature.
Starbucks doesn't. Dunkin Donuts, whose coffee is generally quite well
regarded, doesn't. Burger King and Wendys don't. Further, percolators and
drip coffee machines and espresso machines and most of the other kinds of
device that one would use at home to make coffee don't.

There's a difference between brewing temperature and serving
temperature. Coffee should be brewed at 205, but served at no more than
160 (and 140 is better).

Espresso machines would be a bad comparison, because the coffee cools
off so quickly after coming of the machine.

You make a good point about some of the other fast-food places serving
coffee almost as hot...arguably they would be at fault as well.

I think the best solution would be to serve the coffee somewhat colder,
but use a cup that insulates better so it doesn't cool off as fast.
Personally I drink my coffee in an insulated mug and it keeps its
temperature for hours.

Chris