I found this in the newspaper. It's been changed slightly for back country. I had a hard time deciding if this was food, camping, or science... Enjoy!
How it Works
When you add salt to ice (or snow) you lower the freezing/melting point. Thus ice that normally melts at 0C now melts at -5C. This means that all the energy needed to change ice to water (heat of fusion) is sucked from somewhere like your ice cream. Meanwhile your ice cream turns solid because it is donating all that energy to melt the ice, but then freezes because its freezing/melting point is higher. Nifty eh?
On With the Ice Cream!
Enough with the science, let's cook...or uh, bake...ummm, mix and shake I guess???
Stuff to put in/use
Ice Cream
- 1 cup milk
- 2 tbsp coffee whitener (Only needed if your using powdered milk)
- 2 tbsp white sugar
- 1/2 tsp vanilla extract
The Magic
- 1 large freezer ziploc bag
- 1 small freezer ziploc bag
- 3-4 handfuls ice or snow (not too picky here, ice is better)
- 1/2 cup course table salt
How to put it all together
- Reconstitute the milk if your using powder. I can't tell you the ratios because they are all different.
- Put the milk, coffee whitener, sugar, and vanilla extract into the small ziploc bag. Squeeze out the air before sealing the bag.
- Put the ice, salt, and small ziploc bag into the large bag. Squeeze out the air and seal.
- Massage the bags vigorusly for 10-15 minutes.
- Eat the contents from the small bag, making it plainly obvious how amazingly good it is.
Flavors
Experiment! Honey, chocolate chips, fruits, maple sugar, lemon/lime juice, etc, etc. Or go fancy and look up custard based ice creams. Denser creams are even better (half and half, whipping cream, whole milk).