The problem: cloudy ice cubes, with unsightly bubbles in the center, even though you started with clear water and a clean ice tray.
The answer: start with hot water, not cold.
The reason: hot water holds less dissolved air than cold water. Those bubbles in the center of an ice cube come from air dissolved in the water.
Bubbles In The Center
Bubbles usually form at the center because ice cubes usually freeze from the outside. The top, bottom, and sides of the cube freeze first, leaving a liquid water center.
As the cube continues to freeze, dissolved air is forced into the liquid center. Air can’t freeze at these temperatures, so when the liquid center of the ice cube finally freezes, the air comes out of solution and forms bubbles in the ice.
Less Dissolved Air
Hot water has less dissolved air to begin with, so it makes fewer bubbles when it freezes. To convince yourself hot water holds less dissolved air than cold water, think of what happens when you heat water in a saucepan on the stove.
Long before the water gets hot enough to boil, tiny bubbles form on the bottom of the pan. Those tiny bubbles are air coming out of solution as the water warms up. The same thing happens in your hot water heater.
Or, think of an aquarium: if the temperature is too warm, fish die, partly because the warm water holds too little oxygen (there are some fish who have adapted a lack of oxygen). Getting back to ice cubes: if some dissolved air has already been removed from water by heating, less air will be left to emerge as bubbles when you freeze the water in an ice tray.
So, the secret to making clear ice cubes is to start with hot water.
Ronald A. Delorenzo, Problem Solving in General Chemistry (1981), p. 240.
Step 3: Place it Outside
Leave the Cooler open and leave it outside under an awning or cover to prevent snow falling on it. In the photo above you can see a photo from an earlier trial where one corner was snowed on and was both cloudy and warped.
Why Clear Cubes?
Your probably wondering, “Hey Discount Filters, what’s the big deal with clear ice anyway?” Well, you’re in luck. Because that’s what we are going to illustrate here!
Clear Ice Cubes vs Cloudy Cubes
Here’s a snapshot of these two types of ice:
- Clear ice lasts longer, melts more slowly
- Cloudy ice melts faster
- Clear ice tastes better
- Cloudy ice sometimes has a flavor due to it being less pure
- Clear ice is purified
- Cloudy ice has impurities trapped in it
- Clear ice has a restaurant quality look and feel
- Cloudy ice does not
Clear ice cubes are better in a lot of ways that stem from the high level of purity that consumers get when they use clear ice.
You can’t usually achieve clear ice just by buying filtered water at the store. You have to use certain techniques at home to make sure water is ultra-pure.
What Makes Cubes Cloudy
As mentioned above, cloudy ice is cloudy for a reason. It’s because it has impurities trapped inside the ice. There are two types of common impurities found in ice:
- Minerals; and
- Particulate matter from the air
Ensuring water is very pure before it is frozen is essential for getting clear ice.
Found in Your Ice
There are a number of minerals and naturally occurring trace elements that could be hiding in your cloudy cubes. These include:
- Calcium (mineral)
- Magnesium (mineral)
- Potassium (mineral)
- Sodium (mineral)
- Phosphorous (mineral)
- Copper (trace element)
- Chromium (trace element)
- Iron (trace element)
- Zinc (trace element); and more
While the above elements and minerals are good in healthy amounts and contribute to a number of good things like bone strength and cellular growth, there are also toxins found in tap water:
- DDT; and more
There’s a health benefit to getting your water as pure as possible. But water treated with chemicals to make it safer to drink, like tap water, means purifying chemicals contribute to the cloudiness.
Reducing water to it’s purest form won’t necessarily prevent exposure to minerals or toxins but can help you from putting some of the bad stuff into your body.
Restaurant Quality Experience
Having clear ice cubes for drinks gives you a restaurant quality experience.
It lends itself to a number of summer activities like hosting a BBQ for friends or enjoying a quiet drink alone on your back porch, listening to the sounds of nature.
Regardless of what you choose to do with your ice, there’s something so spontaneously summer about invoking the ambiance of a restaurant at home.
When it comes to making ice cubes, let’s get one thing clear. Cloudy cubes just won’t do.
Water Preparation Instructions
Now that you know why clear ice is important to your summer fun, let’s tackle how to make it.
The secret is in the water, so before we get into methods of freezing ice, let’s look at some simple things you can do to treat your water at home:
- Step 1: Use distilled water
- Step 2: Boil water to allow excess air to escape the water
- Step 3: After boiling, cover water and let it cool
- Step 4: Boil again and cool before freezing
So, that’s it, right? End of story?
No, not by a long shot. This is just the start of your clear ice adventure. So strap in and getting ready to select the best method to freeze your water.
Three types of Ice Blocks
Before I cover the steps to make crystal clear ice, I should tell you there are three basic types of Ice used for sculptures and carvings. They are called clear ice, can ice and natural ice. Can ice is just what is says, ice made in a large mold or can and takes on a cloudy look in the middle of it, it’s typically used when one has a large sculpture and doesn’t
want the lines from assembling blocks of ice. Clear Ice is typically what I use and takes quite a bit of time and process to create it. It is also the process that I will describe in this article. Lastly, natural ice is just that, it is removed from the environment like a lake or river. It typically is not as cloudy and takes on a very blue color which makes it pretty cool to carve and display. Ice freezes from the outside in which makes the feathery, cloudy appearance.
So, here is the process I use and it may be different from most but it works for me. The ice starts out as liquid obviously placed in a large metal bin called a block maker. Ours are double block makers and we have 3 of them currently. So we can make 6 blocks at a time but it takes 3 days from start to finish to produce the finished product. So whether we need it for a carving or not, we are typically making ice and storing it for when we need it.
So the first step is to use clear plastic that is cut and measured to fit the bins, we line the block maker with it to make the ice easier to remove, then we fill the bins with water. Some have asked if we have to use Distilled water but this is not the case because of the process we use, also distilled water does not guarantee that you will not have feather or cloudy ice.
The next step is to use a pump similar to one that you see to run a small fountain to move the water around and circulate. These are attached to a metal bar that sits across the top of the Ice block maker as seen above. These pumps constantly move the water
around and causes the air bubbles and imperfections to move to the top of the ice as it freezes. This allows us to isolate that cloudiness to one area which we can trim off after the ice freezes. In the photo to the left, I have lifted the pump slightly so you can see what it is doing to the water as it freezes. The end result is large block of ice that has about 2-3 inches of cloudiness just on the top of the block. At this point, we remove the ice with a crane that is designed to fit around the ends of the ice and lift the block out of the maker with the plastic around it. I have this shown in the picture gallery below. Once we are ready to use the ice for carving, we use a dumb waiter that I created (I like to create things) to move the ice from the basement to the upper level or outdoors. I then take it on-site or to my carving lab to design the ice sculpture.
Once the block is removed, it will sit in the freezer for a few days before we slice off the imperfections. I have created my own cart complete with wheels to move the ice around in my work area. I have also created a custom ice trimming template with a chain saw attached as seen below in the gallery. I’m pretty proud of this device and it works really well, kind of cuts the ice like butter. As you can see in the final photo in the gallery, the trimmed piece is separated and we will reuse it to create more blocks. The finished blocks weigh around 300lbs and are typically 20 inches by 40 inches. Take a look at the gallery below as we show the steps to create the ice and the finished product. If you ever visit the restaurant and want to see it in action, don’t hestitate to ask.
View the gallery for Steps to make a clear ice block
Double Ice Block Maker Small Fountain Pump Homemade Ice Block Lift Large Block of Ice Notice the only area that is not clear Custom Ice Block Trimmer Removed Imperfections End Result Clear Block of Ice