Easy, Illustrated Instructions on How to Make your Own Slushy Magic Slush Making Cup
There was a mini-crisis the other day when our daughter's Slushy Magic disappeared.
Slushy Magic, for anyone who doesn't know, is a plastic cup which can quickly freeze juice and transform it into a fun icy slurry. I was skeptical before we tried it, but sure enough, it works!
The cup contains three soft cube-shaped bags, each about the size of a chicken egg. These bags are filled with a mysterious cold-conducting fluid.
When a cold drink is poured into the cup, the very low temperature of the cooling cubes freezes the drink into a slushy mix of juicy ice.
This freezing happens in about 90 seconds, and the cold transfer is assisted by vigorous shaking.
The shaking might not be vital, but the ice crystals probably also taste better when they smashed into a small size.
Obviously this contraption is a hit with the kids, so when we couldn't find it, a deep sorrow descended upon our household.
I visited Amazon.com to find a replacement. There I discovered several generic versions of the product, and stumbled upon to aumont's review of the Super Slush Cup.
At the bottom of her three star review, she wrote
Interesting note: they seem to be filled with salt water.
Depite conducting one hundred ice-related experiments over the years, I hadn't thought to reproduce the Slushy Magic. I had assumed that the cubes were a technological breakthrough, but they weren't. The cooling cubes were just regular salt water! Of course they used something innocuous, those soft cubes are bound to break open and leak into kids' drinks. One minute later I was mixing my own vat of salt water and decanting it into two ziplock sandwich bags.
As for a shaker cup, I needed something large, but with a tight lid. These are uncommon. Target offered a few durable cups, but they were approximately the same price as a new Slushie Magic. These homemade saltwater bags were also going to be a tough fit for any tall cup. I opted instead for a flat tupperware container. I assumed my kids weren't going to care about the shape of the container, and the tupperware satisfied my requirement for a slush-tight seal on the container.
When the kids awoke the next morning, the slushy tupperware container magic was ready to try. Ferris shook it up and it worked like a charm!
The original Slushy Magic does a pretty cool trick: The three cooling cube-bags use up most of the volume of the cup, so the amount of juice it has to freeze is fairly manageable from a heat-transfer perspective: perhaps just 4 or 5 ounces.
If the juice wasn't refrigerator cold to begin with, or if you tried to add more juice than recommended, it was doomed to fail.
The faux Slushie Magic worked really well! It only took a few seconds before everything was frozen. Unfortunately one of the bags had a tiny leak, which resulted in a disgusting salt slush. My next try would employ sugar water in the cooling bag, slightly more expensive, but unable to ruin the taste of a drink.
How to make your own Slushy Magic Cup
1. Mix one cup of sugar into two cups of water. This will be the cooling fluid.
2. Mix throughly. The water will turn thick and clear.
3. Pour the sugar water into a ziplock sandwich bag. You can use a friend or a funnel if you don't want to spill the first one all over the counter.
4. Seal the bag, squeezing out most of the air. Having too much air in the bag will keep the icy syrup inside from cooling your juice when you are shaking them together. You could also use a Seal-a-Meal device, if you have one.
5. Find a suitable Tupperware, plastic or glass container. It should have a well-sealing lid. I recommend a boxy rectangle, and I happened to have the perfect size.
6. Put the Tupperware, syrup bag and lid in the freezer for four or five hours. Put the juice into the refrigerator. After this period of time, the syrup bag will be frozen or nearly frozen.
7. Pour about one cup (8 ounces) of cold juice into the container, on top of the syrup bag. Resist the urge to fill the whole container. Having three ounces of slush is better than having 16 ounces of really cold apple juice. Seal the lid.
8. Enlist a child to shake the Tupperware. It only takes a minute. Do not shake babies.
The shaking keeps the ice crystals small and aerated, and makes sure the coldness of the syrup bag has an effect on all of the juice. Shaking doesn't create coldness. If there isn't enough coldness in this package, vigourous shaking isn't going to freeze anything.
That's it! Ice cold juice slush! You can use a straw or a spoon. You will have to work around the syrup bag to scrape all of the slush out, but that's part of the fun.
If the sugar bag has a leak, this will be extraordinarily sweet slush. Your kids won't mind at all.