How To Keep Coffee Piping Hot

Add cream:

1) Black coffee is darker, and dark colors emit heat faster than light colors. As such, “by lightening the color of your coffee, you slow the rate at which it cools,” if only slightly.

2) The Stefan-Boltzmann Law (apparently) says that hotter surfaces radiate heat faster� than cooler ones. So if you add cream to a cup of black coffee, it might lower the temperature of that cup of coffee. However that cup could still cool at a slower rate than a cup of hot black coffee.

3) Finally, and perhaps most importantly, “adding cream thickens the coffee (adds viscosity), so it evaporates slower.” And, in turn, less heat gets carried away by the evaporation.

(Video of cream being added to coffee in super-slow motion via Modernist Cuisine)