Tag: ice blocks

  • Clear Ice Blocks at Home in an Igloo Cooler

    This post describes how to make a clear block of ice using a picnic cooler. Since I first wrote it in 2009, I have figured out a lot about ice, but this was the defining post for what would become known as "directional freezing." What is Directional Freezing? (the basic theory behind clear ice). 

    An index of all of the ice experiments on Alcademics can be found here. It's also a great place to start. 

     

    Before I figured this out, I tried many other experiments. 

    Early experiments were:

    And I had success with:

    I also learned some ways to cut ice into big chunks.

    Now I am trying to refine what I call the Pond Method, the concept that if we freeze water from the top down only (and not outside-in), all the trapped air that makes cloudy ice will be the last to freeze on the bottom of the container, rather than in the middle.

    In the last attempt I used a collapsible beer cooler. I had good success in getting clear ice, but found it really hard to get the ice out of a cooler. 

    Coolers

    This time I tried freezing water in a hard-sided plastic Igloo picnic cooler. Initially I left the cover closed, but after two days it had only barely started to freeze (a good sign for its insulating abilities) so then propped the cover open.

    Iceincoolers

    After a few days when the water looked almost completely frozen and I could see some cloudiness forming at the bottom, I removed the cooler from the freezer. I turned the cooler upside-down and waited for the ice block to drop out of the cooler. Presto! It was ready.

    There was a little unfrozen water at the bottom of the block (with only about a centimeter of ice covering it). This was easy to drain.

    Full block outside cooler (6)

    Then I just cut off the bottom cloudy part and had a big chunk. Easy!

    Once again, the secret to cutting ice is to score it about a centimeter with a knife or saw, then chip it away with an ice pick and hammer.

    Clearblock1s

    Conclusions:

    • I'm really surprised the cooler didn't crack after the ice expanded, but maybe it didn't because there was a little unfrozen water remaining.
    • This Igloo cooler is a totally workable vessel for making clear ice blocks in my home freezer. Hooray! Luckily it is of a shape that allows for easy removal of the ice block.

    Future experiments:

    • In this first experiment with the cooler I set the freezer temperature on the lowest setting. I'll see if this matters for clarity or if I can use the high setting for faster freezing.
    • I also want to try a disposable Styrofoam cooler (if I can find one this winter) just because there is no worry if it cracks, and this is the most reproducible vessel for other people to try at home.
    • I should attempt to find a flexible insulating material that can be made into other shapes, such as a tall and skinny shape (thermos?) that would more easily fit in the freezer and can make smaller cubes.

    Here are more clear pictures of the ice pulled out of the cooler with some of it unfrozen, and it after smashing off the unfrozen part. 

    Clear block_tn
    Clear after removing shell_tn

  • Cutting Corners to Make Clear Ice

    In an ongoing set of experiments I've been trying to make clear ice at home. I've tried:

    With some success on the last one. While what would be ideal would be to produce one giant solid block of perfectly clear ice, I haven't figured that out yet. However if the ice is going to be used to shake with or for cooling individual beverages, you don't need a giant block- just big chunks.

    There is a way to accomplish this by cutting corners. And tops and bottoms. We've seen how the air bubble makes the cloudiest part of the ice in the center in vertically-frozen water, and mostly along the bottom of horizontally-frozen water.

    making clear ice

     And I've also found that horizontally-frozen water usually has an edge of very clear ice.

    Clear ice around the edges of the pan of ice

    So with my ice pick, I just cut off the clear edges separated the top from the cloudy bottom
     of the pan ice (easier than you'd expect, as the cloudy ice breaks off easily), and cut around the cloudy middle of vertically-frozen water to end up with a big bowl of clear ice.

    a bowl of very clear ice

    Conclusions: You can make clear ice by cutting around cloudy ice frozen in large blocks. However, you waste about 85% of your ice, and a lot of time.

    An index of ice experiments on Alcademics can be found here.