The deeper we whisky lovers get into our passion, the more we care about the details. Close attention is paid to how a whisky is made, the maturation technique, and, for cocktails, the freshness of the ingredients used. So it follows that taking care when adding ice to our prized whiskies also matters. And that means learning how to make it as clear as possible.
“The benefit of clear ice is that there is more control of the water content and temperature you are looking to achieve,” says Sean Meagher, head bartender at Wm. Farmer & Sons in Hudson, New York. Jordan Hughes, founder of High-Proof Preacher and a bar industry photographer well-versed in the home-bartending game, agrees that quality ice matters as it can play a crucial part in your cocktail or rocks pour. “So it makes sense to use the best ice I can make, or get,” he says. “There’s also an aesthetic benefit—everyone loves the look of clear ice—but [controlled] dilution is probably the biggest benefit in my mind.”
Nobody likes watered-down whisky, and large ice allows for a slower rate of dilution because its surface area to mass ratio is significantly smaller than that of a piece of smaller ice, or multiple cubes. While clear ice doesn’t necessarily melt slower than cloudy ice—assuming they’re both the same size and shape—the pristine water from clear ice adds a silkier mouthfeel to your dram and has fewer impurities. Plus, the artisanal touch of a clear chunk of ice that you handcrafted will always impress friends and guests—the visual appeal alone is worth the effort.
Now, on to what makes ice clear, and how to make it.
The Science Behind Clear Ice
Without turning this into a physics lesson, here’s what to know about clear versus cloudy ice. Cloudiness is caused by light being dispersed. Ice made at home or in most commercial freezers has lots of mineral impurities and air bubbles frozen in relatively small ice crystals. These impurities and small crystals create many surfaces within the ice that scatter light; since the light cannot travel in a straight line, the ice appears cloudy. This is where directional freezing comes into play.
The directional freezing method—made popular by alcohol writer and educator Camper English, founder of Alcademics and Cocktailsafe.org—replicates the way water freezes in a lake: from the top down, and typically at a slow rate. In a lake, the water freezes this way because it is insulated by land on all sides; as a result, 99% of the water’s impurities are pushed to the bottom, leaving the purest ice at the top. Sounds simple enough, but most ice molds freeze from all sides, creating cloudiness in the end result.
It doesn’t matter what kind of water you use, whether boiled, distilled, or filtered: None of these variations affect the clarity of the ice. “This is not true now nor has it ever been true!” English says. “Boiling water does not make clear ice. It may make ice a little bit clearer than without, but it makes no significant difference compared to using directional freezing.” There are two methods of directional freezing to try at home—one more involved than the other, but both equally as effective.
Making Clear Ice the Easy Way
The easiest way to get clear ice is simply to buy an ice mold designed for directional freezing. “I used to do the whole cooler method [see below],” says Elliott Clark of Apartment Bartender. “But I got tired of the hassle, so now I just use clear ice molds.” These molds are indeed hassle-free, requiring nothing more than patience as they take 24 hours to fully freeze “True Cubes or Wintersmiths are what I use at home, and they’ve never let me down,” says Clark. True Cubes yield four 2-inch cubes, while Wintersmiths has a variety of mold options that includes spears for long drinks (like a Whiskey Ginger), spheres, and two different-sized cubes
Making Clear Ice Using the Cooler Method
The cooler method is the “OG” clear ice-making technique for home enthusiasts. One of the benefits of using this method, rather than buying a clear ice mold, is that it typically yields more ice. The downside, however, is that it takes a bit more work to harvest the ice—you’ll have to cut it into serving-size cubes yourself.
Start with an insulated cooler, like the kind you’d take to the beach or on a picnic; make sure it will fit in your freezer. “Just fill it with water and put it in the freezer without the lid,” English says. “The first part to freeze [at the top] will be clear and the bottom of the block will be cloudy.” The process can take several days, but English says the clear ice can also be pulled out before the whole block freezes, after 1-2 days.
When it comes to cutting the large ice block, Hughes recommends a few key tools: a serrated knife (he recommends buying something affordable from a store like HomeGoods or Marshalls), a cutting board, and some cut-resistant gloves, like these from Stark Safe, for safety. “Some sort of hammer or wooden mallet is also helpful for making the cuts,” he adds.
How to Cut the Giant Ice Block
1. Take the cooler out of the freezer (after two days), and flip upside on a cutting board.
2. Slowly lift the cooler up to remove the block of ice, then clean any shards of ice, or water, from the cutting board.
3. Measure 2 inches across the length of the block, and lightly cut with a serrated knife to make indentations where you’ll make the first cuts.
4. Once the whole length is marked, place the serrated knife in the indentations and hit the back of the knife with a mallet to separate the ice. Repeat across the length, aiming for four columns.
5. Take the columns of ice from the first cuts and repeat step 3 by making 2-inch markings along the length to outline cubes. Then, repeat step 4 to cut out the cubes.
More of a visual person? Watch Elliott Clark of Apartment Bartender cut his own ice at home.
Store the cut cubes in a ziplock bag in the freezer until you’re ready to use them. (Pro tip: To make sure that your perfect ice doesn’t crack when you pour whisky over it, allow the ice to temper—sit out at room temperature for 5-10 minutes—before adding it to the glass.)
All that’s left is for your guests to applaud your ice-making expertise.