Football Ice Cream

Is it hot where you live in the summer? What if I gave you a recipe for making ice cream that doesn’t require an expensive ice cream maker, hours of churning, and can be made to any flavor you can dream up? (Even dairy-free if needed?)

If you’ve got a backyard full of busy kids that seem to constantly be in motion, then this is the project for you.  The best part is, you don’t have to do any of the churning work… the kids will handle it all for you!

This experiment is simple to set up (it only requires a trip to the grocery store), quick to implement, and all you need to do guard the back door armed with a hose to douse the kids before they tramp back into the house afterward.

One of the secrets to making great ice cream quickly is [am4show have=’p8;p9;p11;p38;p92;p23;p50;p80;p88;p101;’ guest_error=’Guest error message’ user_error=’User error message’ ] to be sure that the milk and cream is COLD.  I will make this particular recipe, it’s usually with hundreds of kids, and our staff will stuff the milk products in the freezer for an hour or two or under hundreds of pounds of ice to make sure it’s super-cold.

If you’re going for the dairy-free kind, simply skip the milk and cream and add a bit of extra time to the chill time of your substitute ‘milk’.  We’ve had the best luck with almond and soy milk. Are you ready?

Here’s what you need:

Materials:

• 1 quart whole milk (do not substitute, unless your child has a milk allergy, then use soy or almond milk)
• 1 pint heavy cream (do not substitute, unless your child has a milk allergy, then skip)
• 1 cup sugar (or other sweetener)
• 1 tsp vanilla (use non-alcohol kind)
• rock salt (use table salt if you can’t find it)
• lots of ice
• freezer-grade zipper-style bags (you’ll need quart and gallon sizes)

Download Student Worksheet & Exercises

How does that work? Ice cream is basically “fluffy milk”. You need to whip in a lot of air into the milk fat to get the fluffy pockets that make this stuff worthwhile. The more the kids shake the bag, the faster it will turn into ice cream.

Why do we put salt on the ice?

If you live in an area where they put salt on the roads, you already know that people do this to melt the ice. But how does salt melt ice? Think about the chemistry of what’s going on. Water normally freezes at zero degrees Celsius. But salt water presses lower than zero, so the freezing point of salt water is lower than fresh water. By sprinkling salt on the roads, you’re lowering the point at which water freezes at. When you add a solute (salt) to the solvent (water) to alter the freezing point of the solution, it’s known as the “freezing point depression”.

Tips: Don’t use nonfat milk – it won’t work with this style of ice-cream making.  if you’re adding fruit or chocolate bits, make sure you get those cold in advance too, or they will slow down your process as they heat your milk solution. (We usually add those bits last after the ice cream is done.)

IMPORTANT: Do NOT substitute dry ice for the water ice – the carbon dioxide gases build quickly and explode the bag, and now you have flying bits of dry ice that will burn skin upon contact.  That’s not the biggest issue, though… the real problem is that now animals (like your dog) and small children pop a random piece of dry ice into their mouths, which will earn your family a visit to the ER. So stick with the regular ice from your fridge.

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