The Secret to Making Soft Crushed Ice, Sonic-Style

In high school, I frequented the local Sonic Drive-In for good reason: Two of my best friends worked there, the outdoor patio serves as a decent hang-out spot in a pinch, and their soft crushed ice. Sonic's ice, which is famous in places where Sonic is common (i.e., the South and the Midwest) is more cloud layer than pack of icebergs.

It floats merrily along the top of a limeade like a sky full of cumulus on a sunny day. Riddled with holes, the pellets give immediately when you chew them—it's extremely satisfying ice. And in 2005 in Knoxville, Tennessee, you couldn't get it anywhere else.

As an adult, I encounter crushed ice more frequently in its favorite cocktail—the Mint Julep—than at Sonic. Not that I drink them all the time, but with the Kentucky Derby fast-approaching (the actual race is this Saturday), it seemed a good time to find a way to get soft crushed ice at home.

And for the purists out there, I know that a julep tastes just dandy with regular crushed ice, which isn't the same as soft crushed ice—the latter is just my personal preference. So before I go on, let's define some terms (that I've made up) to distinguish between ices:

• Hard ice: What typically comes out of your freezer, clear through and rock-hard until melted. Available in many shapes and sizes depending on the tray you use. Large cubes of hard ice are advantageous when only the slowest of melts is desired (see: whiskey on the rock(s)).
• Crushed ice: Tiny pieces of hard ice, some shard-shaped and some pebbly-looking, which are solid enough to be crunched but small enough to melt away quickly. Traditional in a julep. Can be made from hard ice in a crushed ice machine, in a Lewis Bag, or with a muddler or mallet.

• Slushie ice: This is what's in your frozen margarita, your kale smoothie, and your Slurpee. Make slushie ice by putting any drink through a blender with plenty of hard ice until the machine runs smooth.
• Soft ice: Medium-sized pellets aerated with many tiny holes, making them at once cube-like but also easily crushed between chompers. Becomes softer the longer it spends in a beverage. The most satisfying of ices.

Mint Julep

View Recipe

When I poked around for a trusty internet hack about how to make soft ice, I found mostly recommendations to hit up a Sonic (they sell big bags of the stuff, from their special ice machine, because people are obsessed with it). Others posted all the good ice crushing machines of the world, from muddlers to plug-in contraptions. But it was on a thread at MetaFilter that I got the best suggestion: Use carbonated water to suspend bubbles in normal ice cubes, which will make them aerated and therefore "soft."

I'll cut to the chase—it works. Here's how to make soft crushed ice at home:

1. Carbonate some water.

Or buy the fizziest bottle you can find (a big 2-liter of club soda would do the trick if you need lots of drinks for a derby party). The bigger the bubbles, the better.

2. Freeze it.

A medium-sized cube, about a half-inch to 3/4-inch squared, is just about the perfect size for soft crushed ice (fits in mouth easily, doesn't melt too fast so you get some super-soft ones at the end of your beverage)—but it's also nice to have some tiny snowier bits floating in between them for those first sips.

Depending on how large you like your pieces, fill regular ice cube trays half or all the way full before moving onto the next step. They'll only need a few hours to set, but they'll still be soft on Saturday if you freeze them today and leave them in the freezer for days. They'll be cloudy when you pop them out.

3. Crush it.

You can makeshift a Lewis bag by fashioning a satchel from a tea towel and smashing the soft ice cubes in it with a mallet, but I opted for a muddler and heavy glass. Just give each cube a resounding whack rather than smashing them to bits. Having some tiny pellets in the mix is no bad thing. Now scoop it all into a glass, top with beverage, and slurp away.

Big chunks are totally fine—they won't melt as quickly. (The larger pieces from this test lasted for the entire time it took me to drink the glass of water, and the best part is that they get softer and softer over time.)

Even non-ice crunchers can enjoy soft ice. I handed the above glass to my colleague Caroline, who has better manners than I do and doesn't chew her ice, and she tried crunching it. "I am not afraid of cutting the inside of my mouth on it," she said of the soft ice, and also that it reminded her of snow, was more "pebbly than glassy," and that she could envision being very happy with "a cocktail poured over a mound of it, sno-cone-style."

So if you're thinking of throwing a Derby party, or even just pouring a julep this coming Saturday, give soft ice a try. You might not know what a Sonic is, but that won't matter a bit.

How do you like your ice? Let me know in the comments.