The Secret to Ultrasmooth Ice Cream: Liquid Nitrogen [Video]
Its texture is at once ice-cold and silky. But how does basic chemistry make this frosty, popular treat a reality?
A soft, creamy treat: Because of its ultralow boiling point: –196 degrees Celsius, liquid nitrogen can be used to flash-freeze food without damage to cells. Image: Wikimedia Commons
Last year Americans spent roughly $20 billion on ice cream. With the return of fair-weathered spring, grocery stores are once again stocking up on the popular, refreshing treat.
Rather than heading to the grocery store, you can concoct super-creamy forms of this American favorite almost instantly at home, provided you have a key ingredient: liquid nitrogen. Yale University professor of mechanical engineering and materials science Ainissa Ramirez demonstrates how to make the treat—while conducting a mini science experiment—within minutes.
Liquid nitrogen, aka LN2, is an odorless, colorless, nonflammable element famous for its extremely low boiling point: –196 degrees Celsius. Because it vaporizes at such a low temperature, the gas it emits is frigid. Food-makers can therefore use the stuff to flash-freeze fresh items, such as herbs, which prevents water inside from forming large ice crystals that would damage cell membranes. It’s also used to give ice cream its velvety texture.
In this video, part of her Science Xplained series, Ramirez shows how just a few drops of liquid nitrogen can rapidly transform a bowl of milk or cream into a thick, frozen dessert.
http://www.scientificamerican.com/article.cfm?id=secret-ultra-smooth-ice-cream-liquid-nitrogen
