The Superior Chill: Clear Ice vs. Cloudy Ice
Have you ever looked at the ice they serve you in a restaurant compared to the ice you make at home? You might have noticed that it's crystal clear, while the ice at home is white and cloudy. Why is that? Why should you care?
Restaurant ice is clear because restaurants and bar owners use specialized ice making equipment that freezes ice from the inside out, rather than the outside in, like you do at home. The difference seems small, but it has significant benefits. Clear ice lasts longer, looks better, and does a better job chilling your drink than cloudy ice. But you don't have to go to a restaurant for clear ice. You can make it at home with the right equipment, or the right technique.
What Causes Cloudy Ice?
Cloudy ice is caused by minerals and air particles that become trapped it freezes. All water contains some level of minerals and dissolved gases. Even distilled and filtered water contains small amounts. They're normally invisible because they're suspended amid the water particles, but as water freezes, they get trapped between the ice crystals and show up in ice cubes as white flakes or tiny bubbles. Because of its impurities, cloudy ice is significantly less dense than clear ice and melts five times faster, which is why iot's frowned on by bartenders and restuarnt owners. It dilutes drinks very quickly without chilling it as effectively. It also tastes different. It's sublte, but most people are sensitive enough to detect the difference between clear ice and cloudy ice if given one of each.
How Do You Make Clear Ice?
In order to make clear ice, you need to understand the freezing process the way restaurants and artisanel ice makers do. Instead of freezing water from the outside in, they use specialized ice makers to freeze ice in layers, from the inside out, the way the ice forms in nature.
When ice forms, water molecules come together and form an interlocking crystalline structures because all water molecules have a slight electrical charge. The oxygen and hydrogen atoms that make them up share electrons through the covalent bonds that bind them together, but the electrons aren't shared evenly. The larger oxygen atom attracts electrons more strongly than the smaller hydrogen atoms surrounding it, which means it has a slight negative charge while the hydrogen atoms a slight positive charge. This means that when two water molecules come into contact with one another, they create an interlocking series of connections based around the dipolar attractions between their hydrogen and oxygen atoms. The hydrogen atom affix themselves to oxygen atoms and vice versa. While water's in a liquid state, these connections are short lived. The energy between the molecules continually breaks the electrostatic bonds holding them together and forces them to move around and re-bond with other molecules. When water freezes, the energy between molecules decreases until their electrostatic bonds solidify and become permanent, forming an orderly network of interlocking hexagonal lattices based around the electrical attractions between their constituent atoms.
As these dense formations take shape, they force out any air and minerals suspended between them. If this happens while the water is stagnant, because the water is suspended in a puddle or ice cube tray for example, the outside layer freezes first and forces the air and minerals down into the center. Eventually, when there's no more space for them to move into, they'll get trapped and frozen between the water molecumes. If the water is moving, however, it will be the inside layers that freeze first and the air and minerals will get carried away before they get trapped. This is why icicles are clear while ice cubes are cloud. Icicles freeze in layers. It startes with a drop of water that freezes and pushes its impurities up to the surface. As more drops trickle down, they push the air and minerals away and form another layer of ice on top. The layers build up in this way until the icicle is formed, made entirely of clear ice.
How Does Luma Create Clear Ice Cubes?
The Luma Comfort IM200SS Portable Ice Maker creates clear ice cubes in the exact same way, by freezing water in layers. The ice maker runs a continuous stream of water over a metal tray with a honeycomb design. The plate is cooled by cold air generated from the unit's compressor and pumped up against the back of the plate to reduce it's temperature. The water in direct contact with the plate freezes and pushed any air and minerals up to the surface, where they get washed away by the running water before more ice freezes on top of them. The process continues until the entire tray is filled with ice. Then a signal is sent to the compressor motor. The water flow stops and a small amount of heat is directed up to the tray in order to break the seal around the ice and allow it to fall down into the basket below. In order to prevent waste, the excess water is funneled into a reservoir below the ice basket and pumped back up over the tray. The entire process takes approximately fifteen to thirty minutes to begin producing ice, but once it's begun, it can create up to 28 pounds of ice every day.
How Do You Make Clear Ice Without an Ice Maker?
There are several ways to create clear ice at home, without a clear ice maker, though none are as effective. Besides a freezer, all the items you need can be purchased at your local supermarket.
|Directional Freezing||One Small Ice Cooler, One Large Ice Cube Tray or Ice Mold (Preferably Silicon)||Punch holes in the ice tray and place the ice tray inside the cooler and fill the cooler with water until the tray and the area around it are completely submerged. Place the cooler in the freezer with the top open and wait 24 hours. The cooler will insulates the ice so it only freezes from the top down, rather than from every direction. After 24 hours, remove the cooler. The holes in the tray will have forced any impurities down into the ice surrounding it. Let the ice thaw for 3-5 minutes until it's weak enough for you to break the ice around the tray and remove the cubes. To create a large block of clear ice, simply fill the cooler with water and place it in the freezer. After 24 hours, all the impurities will be trapped along the bottom of the ice block. Remove them by thawing the ice block for 5-10 minutes|
|Double Boiling||One Ice Tray, One Pot or Tea Kettle, One Bottle of Filtered Water||Place the water in the pot or tea kettle and boil it. When the water has cooled, boil it again. Boiling removes dissolved air particles and decomposes suspended minerals. Once the water has finished boiling, pour it into an ice tray. Cover the tray with plastic wrap to prevent dust from settling in and place it in the freezer for 2-3 hours|
|High Temperature Freezing||One Ice Tray||Set your freezer for 30°F or warmest possible setting. Fill the tray with water and place it in the freezer for 24 hours. The water will freeze slowly, allowing the ice to force out any impurities|
Keep in mind that without the use of specialized equipment, all home ice making methods will invariably trap a small amount of gas during the freezing process. Also, when removing ice blocks from coolers, be sure to slide the ice out smoothly to avoid causing any cracks.
When you want to chill a drink, a clear piece of ice is the best way. Cocktail connoisseurs call it "artisanal ice," because of the time it takes to craft it in large quantities. Now that you know how to make it in your home, you can enjoy it any time.