IN THE LAB

LIQUID NITROGEN & ICE CREAM

A Barnard chemistry student explains the science behind making ice cream in the lab

 

WARNING!
Never, ever do this without a Barnard chemistry student present.

 

INGREDIENTS:

• Cream
• Sugar
• Vanilla
• Fruits / chocolate / nuts (anything to be mixed in and to flavor the ice cream at the end)
• Liquid Nitrogen

PREP TIME:
10 minutes

INSTRUCTIONS:
Pour the cream, sugar and vanilla together into a bowl.

Wearing goggles, gloves, and full laboratory attire, slowly — and with great care — start to pour the liquid nitrogen into the cream.

Continue to add the liquid nitrogen until the mixture starts to thicken, but not so that it is too hard, for several minutes. The blender will start to have difficulty turning.

Then add your special ingredients (strawberries or any other fruit of your  liking, chocolate chips, or nuts are always a nice addition) stirring them in with a wooden spoon.

 

A few questions for our Barnard chemistry student:

How is this different from the pint of Ben & Jerry’s or Haagen Dazs I buy in the store?

We’ve actually noticed that using the liquid nitrogen does make the ice cream melt faster. But I also think it’s because we use lighter cream now. The first time that the Chemistry Society tried this, it was pretty hard, and we’d used heavy cream. This time, using the fat free and half-and-half cream mixture made it a bit more crystalline.

Is this safe—some people might read this and wonder if it’s ok to consume nitrogen.

Nitrogen makes up most of the atmosphere, so we breathe it in all the time. It has a very low boiling point, making it very cold. You have to make sure that it boils away  before you eat it, because there’s a danger of frostbite.

How cold is it?

Well, the melting point of ice is 0° Celsius. And the boiling point of liquid nitrogen is -196° Celsius, so it’s super cold.

—Dimitra Kessenides