How to Make Boozy Slushies in an Ice Cream Machine
Here's why I love ice cream so much: when you screw up and get something that's structurally unsound, it's usually salvageable. Vanilla ice cream that's gone icy? Blend it into milkshakes—or a root beer float. Just try that with pie.
If you're making sorbet, especially with a thin base ingredient like citrus juice, you have a relatively small margin for perfect scoopability. On one side lies bland iciness; on the other there's oversweetened slush that will slump off your ice cream scoop into a puddle.
But that's okay, because where sorbet fails, slushies begin. And the easiest (and most fun) way to make them is with booze.
To see why, let's recap how sorbets work. A sorbet is a frozen syrup whipped with air. As it chills in the ice cream maker, the water freezes into ice crystals that get broken up by the machine. Sugar molecules break up those crystals too, but they also form a syrup with the water and lower its freezing point below 32°F.
As more ice crystals freeze, the remaining water forms a more and more sugar-dense syrup until you have a suspension of air and tiny ice crystals in super-cold syrup that won't actually freeze. The amount of sugar you add is directly proportional to the sorbet's final texture, and if you add too much, you get slush that won't hold its shape. You'll also have super-sweet puddles of sugar syrup that never froze and won't integrate into the already-saturated suspension of crystals.
In a slushy, you want an icy slush that won't hold its shape, but you also don't want it to be tooth-achingly sweet. And that's where alcohol comes in. Like sugar syrups, alcohol has a lower freezing point than plain water, and adding it to a sorbet syrup will soften the final sorbet, since it's less frozen than it would have been otherwise. Add enough alcohol and you get a slushy, with two key advantages over sugar alone: 1) you can use less sugar, so your slushy can be lipsmackingly tart with a less syrupy texture. And 2) since you're using less sugar, you won't find those syrup puddles on top of your frozen base.
If you're making boozy slushies, you'll probably want to adjust just how boozy they are for each person you're serving. Once you have a frozen slushy base, it's easy to add in additional alcohol for each serving.
The recipe below makes a rather tart lemon slush with a faint kick of whiskey for a take on a whiskey sour. You can then stir in additional whiskey per serving to your taste—as low as an extra tablespoon or as high as 50/50 whiskey and slush if you like. The room temperature alcohol you add will affect the flavor of your slushy far more than the alcohol frozen into the base.
For an additional layer of flavor and sweetness, line the bottom of your serving cup or bowl with a spoonful of red wine syrup, which will make your slushie the frozen approximation of a New York sour. Use any wine you like, but sweeter and less oaked are ideal. With this tart a slushy, the extra syrup goes a long way.
If whiskey isn't to your taste, you can follow this procedure with gin. Or use light rum and swap lime juice for the lemons for a homemade slushie daiquiri. Have any more slushy ideas? Let us know in the comments.