Due to recent work requirements, I was entasked to investigate the making of ice cream without an ice cream maker but just SALT and ICE.
Despite understanding the theory, I am totally clueless on cooking up an ice cream and decided to do some research online and decided to extract the recipe from this webby:
What you need
½ cup sugar
¼ teaspoon salt
1 cup milk
3 beaten egg yolks
1 tablespoon vanilla extract
2 cups chilled whipping cream
Optional: I change the flavouring to Baileys as I have plenty of this liquor at home =)
1) Pour 1/2 cup of sugar into bowl.
2) Add in a 1/4 teaspoon of salt
3) Add in a cup of milk. Stir the mixture a little. At this point of time, it is not possible for all the sugar to dissolve. So dont bother.
4) Separate the egg yolks and egg white. We will only need the egg yolks for the ice cream. Whip the egg yolks after separation from egg whites.
5) Boil some water in a pot or pan and one the water is boiling, place your bowl of mixture in (3) in. (Do remember to use a low heat). Ensure there is no direct contact between the bowl of mixture and pan/pot. We only need gentle heating.
6) Add in the egg yolk slowly and stir it in well.
7) Finally once bubbles are formed at the edge of yor mixture, it means the eggs are more or less quite cooked and you may remove the mixture out from the pot. Do not wait till the whole mixture is boiling!
8) Add in a tablespoon of vanilla essence.
9) I was a little adventurous and wanted to fast forward to try making a liquor flavoured ice cream, so I added Baileys. YOu may add any amount of Baileys according to your own liking. Well we(Ah li was awake at the point of time and she helped me with the ice cream making experiment and documention) added lots!
10) Finally, add in the 2 cups of whipped cream. Your ice cream mixture is now ready for the freezing process.
11) Now to prepare the "ice-cream maker". Pour about 1 cup of salt on top of a big bowl of ice cubes. You may also opt for crushed ice for better surface contact and results.
12) In order to make the process faster, we did the ice-ream in batches. So we pour the ice cream mix into a smaller bowl (about 1/4 volume of the total ice cream mix). For us we did it the wrong way so we initially use the original big bowl instead of a smaller ones.
13) Place the bowl in for better contact. Start stirring. You may also keep turn the bowl and let it revolve in the ice bath.
14) Here is the actual picture of the right bowl that we use in the end. Much smaller then the one used previously.
15) Our ice cream is forming!!! At this point of time, there isnt a need for your ice cream to be completely frozen like the one we have in the tub. But it is ready to be place in the fridge for the final freezing stage.
16) The salt plus ice mixture makes the temperature drops lower than 0 degree celsius and even the water vapour in the surrounding air is being frozen up!
Not clear about why is that so??
"Salty water freezes at a lower temperature than plain water. But the ice is made of plain water, so it melts at 0 degrees Celsius. Since the ice keeps melting, but the water no longer freezes (because there is only salt water, which doesn't freeze at 0 degrees), the temperature goes down.
The heat gained by the ice as it melts is no longer offset by the heat given up by freezing water (since the water is no longer freezing back onto the ice). The heat gain has to come from somewhere else. It comes from the ice cream and your hands.
The sodium and chlorine in the salt split apart into charged ions, and these ions attract water molecules to form weak chemical bonds.
The resulting compound has a freezing point of -21.1 degrees Celsius (-5.98 degrees Fahrenheit). This is 21.1 degrees colder than ice (37.98 degrees Fahrenheit colder than ice).
When people put salt on the ice on a sidewalk or a road, the ice mixes with the salt, and the mixture of the two solids (ice and salt) produces a liquid, but the sidewalk actually gets colder than it was before.
If we add a different chemical to the ice, such as calcium chloride, we can get an even lower temperature (-29 degrees Celsius, or -20 degrees Fahrenheit).
The final Baileys Ice Cream!!!
Yep this is not our typical 1 solid piece of ice but the creamy frozen texture.
Let me just SAY.........................................,
We are on the road to getting customised home made ice cream for Christmas *victory grinz* this year!!!!