The best ingredient for your cocktails? Crystal-clear ice — here's how to make it at home

• Clear ice melts more slowly, reduces the rate of dilution, and contains fewer impurities than cloudy ice.
• A simple method to make crystal-clear ice is by controlling the direction that the water freezes.
• You can use clear ice molds to freeze your ice into unique shapes that elevate your cocktails.

Whether you're mixing up an Old Fashioned on the rocks, stirring a Martini, or shaking up a daiquiri, ice is important in creating the right texture, temperature, flavor, and appearance.

But here's the thing: Cocktail ice rarely gets the attention it deserves.

It's easy to think that ice simply just chills a cocktail, but when it breaks down and melts, it actually impacts the flavor of the drink. So on top of being more aesthetically pleasing, clear ice makes for a better cocktail.

"Clear ice gives you a more dense, durable ice cube while producing less dilution and a prettier cocktail as well," says Gordon Bellaver, bartender and co-owner of clear ice purveyors Penny Pound Ice.

Unfortunately, the traditional way of freezing ice — in an ice cube tray in your freezer — creates cloudy ice. But there is a trick to make crystal-clear ice at home. Here's what you need to know.

Why is it so hard to make clear ice at home?

"Any cloudiness in ice is an impurity that's frozen," Bellaver says. Water is naturally full of dissolved minerals and tiny air bubbles.

Water doesn't freeze all at once, and as it freezes, the minerals and bubbles cause the ice to freeze unevenly. And, when you freeze ice cubes at home in the fridge or in a tray, the water freezes from every direction. The uneven freezing and suspended minerals create ice that is cloudy, cracks easily, and melts quickly.

By using a technique called directional freezing, it's possible to freeze a large block of ice that is mostly clear. "You basically freeze the ice slowly from one direction by putting it in a mold with insulated sides," says Bellavar.

"It's similar to how a pond or lake freezes from the surface downwards." By freezing it slowly from the top down, the minerals and other impurities in the water sink to the bottom of the block while the top portion of the block freezes clear.

Does it matter what kind of water I use?

As with any other component of a cocktail, ingredients matter. When making clear ice, it's important to use the freshest, cleanest water available to ensure clarity in the finished product.

"You want to use as pure of water as you can get," Bellaver says. Given that much of the cloudiness in ice comes from minerals and other impurities, it makes a big difference if you use distilled or filtered water when trying to make clear ice.

When making ice at home, it's sometimes suggested to use boiling or off-boiling water when filling the mold. "The boiling keeps the minerals and bubbles moving so once it starts freezing, the impurities eventually settle in the bottom leaving clear ice at the top," Bellaver says.

This step is not necessary but can be helpful to try if you're struggling to achieve clear ice when freezing cool water. To try this technique, just fill your mold with boiling water or water right off the boil and carefully put it in the freezer.

How to make clear ice with the cooler method

One way to make ice with directional freezing is by using a container with insulated sides, like a small cooler with the lid removed, to freeze a solid block of ice.

Fill the cooler with filtered water, leaving about an inch of space at the top, and then put it in a freezer for around 48 hours.

Once the ice is solid, remove the cooler and let it sit at room temperature for 30 minutes to an hour to temper the ice. "Tempering is basically a process of strengthening the ice before cutting it or putting it in a drink," Bellaver says. "Sudden change in temperature can cause the ice to crack unexpectedly along weak points. By letting it warm up a bit, you prevent thermal shock and the ice gets stronger."

Once frozen and tempered, the block needs to be broken down. First, the cloudy ice at the bottom of the block needs to be separated from the clear ice at the top. To do this you can use a serrated knife and rubber mallet to score and cut the ice.

Start by scoring the ice with the serrated knife. When scoring, make a shallow cut, about a quarter inch deep, along the surface of the ice on all sides as if you were tracing exactly where you want the ice to be cut.

Then, put the knife along the scoring line and tap it with a mallet. If scored correctly, the ice should crack along lines scored into the ice. To ensure even cuts, only score one cut at a time.

Once the cloudy ice has been removed, repeat the same technique of scoring and tapping to cut the clear ice into smaller cubes. When you have broken the ice down into the desired size and shape the ice can go back into the freezer until it's time to mix up a drink.

Quick tip: The cloudy ice at the bottom of your ice block doesn't have to go to waste. Try cutting it into pieces for shaking cocktails, or use a canvas bag and mallet to make crushed ice for a mint julep or a tiki drink like the Mai Tai.

How to make clear ice using molds

Cutting your own clear ice can be intimidating for beginners. Thankfully, you can use ice molds to get clear ice without scoring and cutting.

"People have become much more attuned to and interested in cocktail making, so there are a lot of new molds and home systems out there that allow you to freeze at home," Bellaver says.

He recommends both Ghost Ice System and Wintersmiths for high-end clear ice molds. Both systems operate on the same basic principles of directional freezing used when making a block of ice.

Molds can also help you achieve unique shapes that enhance the presentation of the drink. Ice spheres are a common and popular shape that works well in old-fashioned style cocktails. "Ice spheres actually have the least surface area of any ice shape so they melt more slowly and dilute your drink less," Bellaver says.

Quick tip: Freezing fruit or small edible flowers into a clear ice cube can add a nice visual flourish to a cocktail. Just make sure to keep your frozen garnish small enough to fit neatly inside each cube.

Insider's takeaway

Clear ice may seem like a matter of aesthetics, but on top of making your cocktails more visually appealing, clear ice can improve your drink by diluting it more slowly. Making clear ice isn't always easy, but whether you freeze a big block and cut it yourself, use a mold, or buy it from a supplier, it can help take your cocktail mixing game to the next level.