Two of the Best Slushie Machines of 2025 for the Cool Summer

No and yes. Slushies rely on the beneficial properties of water: Sugar (and salt) dissolved in water reduces its freezing point below 32 degrees Fahrenheit. Why? Soluble substances like sugar are helpful for confusion. Sugar molecules move randomly, resist melting into ice, and interfere with water’s ability to form hydrogen bonds and become crystalline. Some water molecules freeze, but sugar water does not. Tada! Slush.

When you try to make a slushie with sugar-free candy, or anything without sugar, ice crystals form easily. A stainless steel cooler is filled with ice and paddled on an auger, and the ice cubes or hunks are collected in the slushie machine. The cylinder starts to vibrate, then the machine vibrates, then in the end you can break your machine: Low sugar problems in these devices have not been very reliable, alas. So don’t do this!

That doesn’t mean you have to have huge calories if you want to make a slushie. Not all artificial sweeteners cut down on cold properly, but what Ninja recommends for slushies is allulose, a rare but naturally occurring sugar. 70 percent are as sweet as essential sugars but are not properly processed by the human digestive system. This means they are low in calories and won’t cause insulin spikes – but as with most non-digestible foods, be aware that side effects can include bloating or GI distress for some.

For easy use in a slushie, buy it allulose water. Powdered versions are also available, but to use them, you need to make a simple liquid by heating the powder in water until it dissolves, and then cooling it. If you try to throw allulose powder into your machine with Diet Coke, it won’t dissolve, and you’ll still make ice. Alternatively, I still got ice when I tried this on the Ninja, and had to stop my machine.