THIS EXPERIMENT MUST BE CARRIED OUT IN HYGIENIC CONDITIONS IN THE HOME ECONOMICS DEPARTMENT (APPLIED CONSUMER SCIENCE DEPARTMENT).
USE FRESH INGREDIENTS FROM THE SUPERMARKET, NOT MATERIAL THAT HAS BEEN STORED IN CHEMICAL CUPBOARDS.
USE APPROPRIATE PERSONAL PROTECTIVE EQUIPMENT WHEN USING LIQUID NITROGEN
1. You don’t need a strictly measured recipe but here’s a guideline:
Pour 600mL of cream and the same amount of milk into a large metal mixing bowl.
Add castor sugar to taste (probably quite a large amount, 1-2 cups?) and stir with a wooden spoon to dissolve as much as possible.
Add a splash of vanilla essence (or some recipes use chocolate/strawberry topping to taste).
Pour in some liquid nitrogen – we used a few hundred mL over two or three pours, using a stainless steel thermos filled from our Dewar – and stir vigorously straight away. Don’t add it all at once or parts of it will freeze too hard.
Once made it can melt quickly so eat fast!
2. Generally, we use the cheat’s method because it’s much cheaper and easier.
2L vanilla ice cream (Buy the vanilla ice cream, let it melt and transfer to large metal bowl.)
1 cup Smarties
250ml Choc sauce
Large flat wooden spoon
1L liquid nitrogen
Mix choc sauce into ice cream.
Slowly add liquid nitrogen whilst stirring with wooden spoon adding the smarties as it begins to thicken.
Continue adding liquid nitrogen until completely frozen.
Spoon into small cups.
(Making up an ice cream recipe using cream, etc would just require following the recipe, until it is ready for freezer, then using the liquid nitrogen instead.)
If there is a little nitrogen left over, staff can have a treat with a sorbet. –melt 1 cup sugar in 1 cup water in microwave. Mash up a punnet of strawberries or other fruit. Mix, then and add liquid nitrogen.
3. Buy some tubs of cream (approx 2 tubs for about 20 people for a spoon size taste each) put them in a stainless steel bowl. Add flavouring if desired, we use strawberry, pour in liquid nitrogen and start whisking taking all safety precautions such as goggles, mitts, etc. It doesn’t happen instantly but takes at least 10 minutes and the resultant ice cream tastes different and doesn’t have the same texture as the commercial product, however the kids love making it.
4. Allow 2 litres per class to fully melt (takes a few hours).
Then pour in the liquid nitrogen while stirring icecream. Kids will love it!
5. Buy a tub of ice cream and allow it to melt, or:
Prepare the night before:
3 eggs lightly beaten
50g caster sugar
Evaporated milk 410ml
Heat milk, chocolate, eggs and sugar in double saucepan, stirring constantly until mixture coats the back of a spoon.
Just before adding nitrogen:
Whisk evaporated milk and add. Whip cream and add.
Mix in nitrogen as quickly as possible while the mixture is still well aerated.
Note: the volume of liquid nitrogen is approximately the same as the volume of the ice cream mixture (1 litre)