What exactly are Slurpees made of? I know heavily sugared things aren't particularly thirst quenching, but somehow you'd think even lots of sugar couldn't make ground-up ice not thirst quenching. But it does. What's in there, anyway?
-- Drinking, but still thirsty in the Backcountry
The magikal Slurpee is a concoction of colored, flavored sugar water and a blast of carbon dioxide. (Ditto the Icee.) It is flash-frozen soda pop with a higher sugar-to-water ratio than the liquid stuff in a can. Into the back of the big Slurpee vat go the liquid and gassy ingredients; and through the wonder of technology, out comes very, very cold slush. There's no crushed ice in the recipe.
Inside the Slurpee vat the secret machinery continually mixes the sugary, bubbly stuff in a freezer compartment that keeps it fluid and at brain-freeze temps. It doesn't crystallize into slush until it comes out of the tap. To freeze properly, the sugar balance is critical. That's why you won't find diet Slurpees. At least not yet. But they're working on it. (Oh, whoopee...) No sugary drink will ever quench your body's thirst because it takes a large amount of water to metabolize even a small amount of sugar. Any "refreshing" feeling you get from a cold, sweet drink is just temporary and just in your mouth.