When it is that time of season where it is cold out and a swap to brown liquors occurs, there’s something I like to make to accompany my drink: crystal clear ice. This can most certainly be done in any season but I like to use the outdoors as my freezer and I will show some tips along the way.
Step 1: Prep the Cooler.
The first step is to get a sturdy cooler. Mine is not the best but it gets the job done. Dave Arnold of Booker and Dax in NYC recommends an Igloo cooler. Nowadays, if you have a Yeti, that might be better. Regardless of what type you get, just fill it with water, leave the lid off and cover with cling film. Set it outside when it is cold like I am doing or use your deep freezer.
Step 2: Tips and Tricks
Some helpful tips I found useful:
1) Use a bar mat or a kitchen rag to rest the ice block to catch the melted water.
2) Use another rag or paper towel with your non dominant hand to grip the ice and keep it from freezing.
3) Use a cooling rack on a sheet tray to hold your finished ice cubes until ready to transport to the freezer. This will catch water and make it easy to track. I like to give the cube a little fling to shake off excess surface water before placing in the gallon bag. This will help keep your cubes separate when you place them in the freezer and not form a huge frozen mass once it does refreeze the surfaces.
4) If some pieces do shatter or you want to utilize some side ice that may have frozen, I like to either use them as my stirring/diluting ice or crush them up and use them in a Mint Julep or Swizzle type of cocktail. I usually go with the latter because even if you use those "half moons" from your refrigerators automatic ice maker that are usually cloudy to stir your drink, the cooling and dilution time shouldn't be long enough to dirty up your cocktail before you pour it.
5) Once you remove the cooler from the cold and the ice from the cooler, let it rest a minute or so. You may notice the surface get a little hazy because the block is cooling the air around it. This condition is not ideal to rush in and start carving. Give it time to temper and the surface will start to melt and go clear again. Now is the time to start but be aware that time is a factor. You would not want all your ice to melt away.
Step 3: The Wait & the Why
Now you have to wait until your water freezes. Outdoors, I usually give it 4-5 days depending on how cold it is. In this instructable I left it out there for 4 days and the average temperature was about 25F. If using a "real" freezer I would check it every 24 hours.
Ideally, your block will only freeze on the top making removal from the cooler a lot easier. Like I said, my cooler is not ideal because I shouldn't have to worry about a fully enclosed block with water in the center. But, it is good to address this to see how to manage it should this happen to you.
Let's talk about why you want to use crystal clear ice for cocktails (or skip the rest of this step if you don't care). First, it tastes better. Less impurities means less of an off taste in your drinks. If you use quality ingredients the last thing you want is some nasty ice murking it all up. Which leads me to another point; when mixing cocktails, you should think of the ice as an ingredient. It looks good for presentation and also can aid your shaken drinks. If you made two shaker tins of a classic sour (a drink shaken using a base spirit, simple syrup, and citrus juice) and filled one with crushed ice and the second with one giant cube and shook them for the same amount of time, you would get two totally different results once poured. The drink with the smaller cubes would taste and look good but the one shaken with the one giant cube would impart more bubbles to the drink and taste more crisp. Don't believe me? Try it (or google it).
So, what is the water is doing? Water, being as unique as it is, will freeze from the top down, known as directional freezing. This helps all the fish to not die in winter and let you ice skate. Once this freezing action occurs, all of the air, gases, and impurities get pushed towards the watery center of the block. This is why when you make ice in your refrigerator, the edges are nice and clear but the center is usually "cloudy." Those cloudy bits are gases and impurities that could not escape the icy barrier and got stuck, making your ice not so suitable for a delicious cocktail. Those impurities can and will impart a not so yummy flavor.
That is why we are using A) a large amount of water to freeze, and B) a cooler with the top off.
The large amount of water will take a while to freeze and that slow action aids in the water freezing at 32F. The slower the water freezes, the larger the crystal. The larger the crystal the more transparent it is. The top being off of the cooler also helps force that top down freezing action. As the water freezes on the surface it expands. Ice is less dense than water so the slower it freezes, the less stress occurs and again aids in the clarity. This will force all those nasties to the center of our cube as mentioned earler. We will discard the water once the time comes.
If you Google how to make clear ice, you may have seen some tips on how to help get it...more clear. For instance, boiling the water first, or use water from your filter, or a combo the two. For me, I felt there was no need. I use water straight from the tap. Why? Because the slow directional freezing action of the water is good enough. As long as the whole cooler worth of water doesn't freeze 100%, all the gross bits will go down the drain later.
Well, I cannot prove that "all" of the gross bits go down the drain. That would require a lot of testing and possibly some lab testing like chromatography or a mass spectrum or something. However, if you are concerned about having the least amount of gross bits possible then by all means use filtered water that you boil off.
Step 4: Start Carving That Ice
I used my honing steel from the knife block to poke a couple holes, one at each end, to force the inner water out, (PIC 1). I use a rag and the honing steel placed in the hole to help position the block, (PIC 5). Then, I score the top layer all the way around the block with a serrated knife (PIC 6). Serrated knives, like the bread knife I am using, are good because they score the ice easier and are cheap. Once the block is scored all the way around, I use the handle of the steel and hit the bread knife blade against the score line, (PIC 7).
Clear ice is surprisingly easy to carve. If you were to try this on a cloudy, impure block of ice there would be no guarantee that the score will cut cleanly. The reason being, the propagation of the score throughout the ice will follow the voids of where the gas is trapped and also where the impurities are not where the knife blade is. PIC 8 shows where I scored the block on the corner and hit the knife against it. It is similar to cutting glass. Once you score the glass and hit it, it will break cleanly against that scored part and (hopefully) not shatter.
PIC 10 shows the top sliced off.
Step 5: Marvel at the Cool Pattern
I always love making my own ice because the inner parts of the block always remind me of a giant snowflake. Also, this shows the freezing crystal pattern I mentioned in the Wait/Why step from earlier. (if you stuck around to read all that)
Step 6: Break the Ice
With the thick top layer off, score it to whatever dimension you would want the ice to become. Like before, scoring all the way around helps to break the ice cleanly.
Step 7: Make the Cubes
Repeat for making the cubes.
If you have a larger block starting out and wanted to make ice balls you could do that as well. I tried with one large corner piece and it didn't turn out well. Mainly because I waited until the end to carve it and by that point it was getting too warm and slippery, even with a rag. However, if you just wait for the ice to temper, using an ice pick and a serrated knife make this quite simple. Your first ball may not come out perfect but with a little practice you'd be surprised by how well it turns out.
I like to make two main sets: Cubed cubes for a Rocks glass and longer rectangular pieces for a Collins glass.
I like using the rectangular ones for a G&T or a Tom Collins.
What makes using clear ice more suitable for such drinks is...you guessed it, the lack of impurities. With less impurities on/in the ice you use, the less chance of creating a nucleation site for the CO2 in the tonic or club soda. What does that mean exactly?? Much less fizzing which means it won't go flat as quickly. This keeps that CO2 in solution and popping out on your tongue and not into the air making your drink very crisp and delicious.
Step 8: Side by Side
The results of clear ice versus traditionally frozen fridge ice.
The ice using the mold even shows, if you look closely, how the impurities flow towards the center. You can see how the ice on the 1st and 3rd row have the outer corners clear but the inner corners are cloudy as all get out.
Step 9: Now Enjoy a Drink After All That Carving
So that is that!
I hope you enjoyed this instructable and try this out for yourself.
I know I reference the hooch a lot throughout but don't let that hinder you if that isn't your thing.
You could still make a batch of clear ice for non alcoholic drinks or keep the block huge for a bowl of punch, for instance.