Every year at day camp, we have an outdoor cooking station.  We’ve done sous vide omelettes, hamburger foil packets, hash browns, and of course, ice cream in a bag.

For this yummy treat, you will need:
Sprinkles
A one gallon plastic bag
1/4 cup of rock salt
A quart ziplock freezer or storage bag
1/2 teaspoon of vanilla
2 tablespoons of sugar
1 cup of half-n-half (almond, oat, or soy based unsweetened creamer works too)
3 cups of ice

1. Pour the sugar, vanilla, and half-n-half into the the quart bag.
2. Add anything else you want in your ice cream (see the variations below).
3. Seal the quart bag, making sure to squeeze out as much air as possible and making sure it is well sealed.
4. Gently massage the bag to mix the ingredients.
5. Pour the ice and rock salt into the gallon bag.
6. Place the quart bag inside the gallon bag.  Squeeze as much air as possible out of the gallon bag and seal it.
7. Shake the bag and gently bounce it on a counter or table for 15 minutes or until the ice cream is thick and ready to eat.  The more you mix it, the creamier your final ice cream will be.  If your fingers get too cold, put a small towel around your bag or wear mittens.
8. When ready to eat, wipe off the outside of the quart bag before opening it.  This will remove most of the salt water so it doesn’t get into your ice cream.
9. Spoon your ice cream into a bowl and add the sprinkles!

Variations:

• Chocolate Ice Cream: Add a 1/2 tablespoon of baking cocoa powder and an additional 1 tablespoon of sugar to the quart sized bag before mixing it up.
• Strawberry Ice Cream: Chop a medium sized strawberries into small pieces.  Add them to the quart sized bag before mixing it up.
• Other fruit flavors: You can chop up any berries and most other fruits you like!  However, do not use citrus fruits or other acidic fruits.  The acid in the fruit may curdle your half-n-half.

Other Notes:

• Why Ziplock baggies?  We’ve tried many brands for this activity.  The store brand baggies tend to leak at the seams, which either allows salt water to leak into the ice cream (yuck!) or allows salt water to leak all over your counter (ewww!).  We have not tried Glad brand bags.
• Can you use plastic containers instead?  Yes!  This is a great way to reduce plastic waste. You can put your quart baggie, ice, and salt into a large bowl that has a tight fitting lid.  Shake the large bowl well, just like you would do with the gallon bag in Step 7.
• Why do you need salt? If you tried to turn half-n-half into ice cream with just plain ice, the ice would melt long before the half-n-half froze.  When you add salt to the ice, it lowers the freezing point of the water.  So as the salty ice begins to melt, it pulls heat from anything nearby – like the mixture in your ice cream bag!  This is why they put salt on the roads in places where it snows.  The salt lowers the freezing point of the water (melted snow) that is on the road.  This helps keep that water from turning into dangerous ice.
• Why do you need to shake and bounce your bag? Ice cream is an emulsion.  That means it’s a mixture of several things that don’t normally like to mix – like oil and water!  When you shake the baggie, the fats and water in the half and half break up into tiny drops that are all mixed together.  If you stop mixing, the tiny drops group together until the fats and water are separate again. When you keep shaking while also making it freeze,  the little drops of water form ice crystals that break into smaller crystals.  These small ice crystals mix with the little bubbles of milk fat and become trapped as the mixture freezes, forming an emulsion!  The more you mix it, the smaller the crystals will be and the creamier your ice cream will be.