At the conclusion of yesterday’s story, the Hamburg sandwich (aka: hamburger) had just began it’s rise to fame at the 1904 World’s Fair in St. Louis. At the same event another famous food was born… the ice cream cone. Not ice cream itself, mind you, just the cone. Apparently the guy at the booth ran out of dishes and on a whim started to roll up waffles to put the ice cream in.
Interesting… but not what I wanted to tell you about today. Rather, my mind got to wondering how ice cream works. If I put a bottle of milk in the freezer it would end up as a solid block of white ice. What keeps ice cream so deliciously soft? To answer that question, the internet introduced me to Professor Douglas Goff, Ph.D. who is an honest-to-goodness professional ice cream scientist. His article told me all the secrets.
Ice cream is suspended in a frozen balancing act. Milk is the primary ingredient, and that is mostly water. (which, in case anybody asks, is what cows drink) Dissolved in the water is plenty of sugar. As a result, the freezing point of that water is “depressed”. When this mix is frozen, some of the water turns to ice, but that just leaves more sugar for the remaining water. Eventually it finds the balance. At -16 degrees Celsius, the optimum temperature for serving up ice cream, about 28% of the water remains unfrozen due to the dissolved sugar.
As another illustration think of a popsicle. That’s just water and sugar stuck in the freezer, but it doesn’t freeze anywhere near as solid as pure ice cubes. It is, however, tougher than that creamy ice cream, so there must be more to it than sugar.
The other thing that keeps ice cream deliciously edible on a moment’s notice is air. After milk, air is the second most prominent ingredient. Technically, ice cream is a foam. The mix is whipped and stirred while freezing to make all the difference between ice cream and a creamsicle.
I’ll leave you with one handy ice cream tip: Eat it now! Between the non-freezing sugar solution and being an oil-and-water emulsion, ice cream is fragile. Every time it gets warm and re-frozen more ice crystals form, and it gets more icy and less creamy. Of course, now you’re eating it in the name of scientific research.
- Source: Finding Science in Ice Cream
P.S. Today one budding scientist will be personally researching the ice cream and cake cohesion factor in the presence of flame. Happy birthday to Blanche!
