Don't mean to correct ya Christian, but it's actually surface area, not mass. Get a lifesaver and put it in your mouth, an ice cube works too and uses the same principle. It's kind of tasty, or cold to begin with. Crunch it up and it becomes more tasty, or cold. That's because there is more surface area to draw the sugary goodness or coldness from. If there were more fins, there would be more cooling effect, but the designers juggle the cooling effect with structural integrity (or resistance to getting fiddlesticked up).
Now go enjoy that tasty lifesaver.