(that's Fahrenheit of course) For that matter......0 degree F aluminum cubes doesn't cool a room temp liquid as much. frozen H2O cools liquid off much much much much faster and more (in total temp drop terms) than equal surface area "cubes" of aluminum, cooled to -20C. (I've done the experiment). I assume this is due to the phase change of the ice.......but part of that escapes me, especially the absolute temp. sink. Can anyone set me straight on this issue? Thanks in advance!