Directional Freezing is a simple method to make crystal clear ice by controlling the direction that water freezes. It was first explained here on Alcademics.com by Camper English (me) in December 2009 after months of experiments. The method has been written about in books, used in commercial products, and is employed in many small cocktail bars around the world.
The Directional Freezing method is: Allow water to freeze into ice from only one direction (one side of a container) and the ice will be clear until the very last part to freeze. The last part to freeze (if allowed to freeze at all) will be cloudy.
The simplest (and original) way to make a clear ice block by directional freezing is to fill a hard-sided picnic cooler with water, place it in a freezer, and allow it to freeze with the cooler's top off. The water will only freeze into ice from the top-down, and only the last 25% or so of the ice block that forms will be cloudy. If the block is removed from the freezer before this point, one will have a perfectly clear slab of ice. Otherwise, the bottom cloudy portion of the ice block can be cut off from the clear part.
How Traditional Ice Cubes Freeze and Why They Are Cloudy
In a traditional ice cube tray, which is not insulated on any side, cool air hits all sides of the tray. Ice forms on the top, bottom, and sides, and freezes from the outside toward the center. It is the center part of an ice cube where it is cloudy and cracked (the cracking through pressure because ice expands as it freezes), while the outsides are typically clear.
We say that ice wants to freeze into a perfect crystal lattice (though want isn't the proper term) and trapped impurities and air prevent it from doing so. When water freezes, it pushes any trapped air and impurities away from the first part to freeze. In a traditional ice cube this is towards the center of the cube. Using directional freezing, it pushes the air/impurities/increase in pressure towards the bottom of insulated cooler (or the last part of any controlled-direction freezing container).
Further Reading
This link to the index of ice experiments on Alcademics lists just about everything myself and Alcademics readers have tried to make clear ice: experiments that failed (such as using boiled water), how to make clear ice cubes, how to make clear ice balls, and using other shapes and containers to save space in the freezer.
Alcademics readers have found numerous ways to make clear ice balls, all taking advantage of Directional Freezing, the process I developed (and named) to make perfectly clear ice using an insulated cooler.
Today's technique is a variation of Making Clear Ice Balls Using an Insulated Mug (probably the least space-intensive method), which I fact-checked here. It's basically just a different insulated mug.
This technique comes from Alcademics reader Cody P, who refined the method. He says, "Doing ice balls like this is just like your article on using a mug, but I left a few mugs too long and they broke from expansion (no big deal if a little can breaks)."
This method uses a beer can in a koozie with the top cut off.
The technique is:
Buy a Yeti Colster. (Another brand might work, but Yeti makes particularly good insulated mugs/koozies.)
Buy some ice ball molds. Cody P said he thinks he bought his (seen in the pictures) at Williams Sonoma, but they're the same size as these 2.5" ice ball molds.
Cut the top off a beer can (and consider filing or taping the top edge to prevent it cutting you when using.
Put the can in the Colster and fill it with water.
Fill an ice ball mold almost full (leave a little room) with water.
Hold your thumb over the hole of the ice ball mold and set it upside-down (hole facing down) on top of the can in the Colster.
Allow to freeze overnight or roughly 8-10 hours. Remove frozen ice ball.
(For first-time readers, what is happening is that the water in the ice ball is the first part to freeze, pushing trapped air/impurities away from the point of freezing down into the insulated mug.)
Though I've not had additional success with boiling water before freezing, Cody P has. He observed:
If you boil the water then the ice comes out SUPER, unboiled gives these air bubbles on the surface but still comes out 100X better than a regular mold.
If you don't pour out some water like I'm doing in one of the pictures, your ball can become an egg as seen in the ice ball picture.
It takes about 8-10 hours to freeze a ball in my freezer but I'm not sure what the temperature is.
If you just want blocks of ice, regular tap water works great since it freezes super slow and is a small volume of water (I think). I found that after about 14 hours I can take out the large block you see and break it in half to use for whiskey and such. They are also decent sized to use an ice ball press.
Pictures of the ice from the bottom of the can are below.
Thanks much to Cody P for the method and for sending in the pictures!
I was in Jamaica a couple weeks ago visiting rum distilleries. Much like on Barbados (where they are called rum shops), Jamaica has a huge number of bars (and churches) per capita.
The bars line the sides of the roads and are usually little more than 1-room shacks. They have the best names, so given that we spent about 3 hours each day (each way) driving around the island, we made it a car game of finding the funniest-named bars on the island.
The San Francisco temporary bar TSK/TSK, which will sometime this year be reincarnated as Horsefeather, featured several alcoholic slushies on its menu.
Slushmaster Mitchell Lagneaux said he was often asked for his advice on how to make them delicious, and rather than writing the same advice over and over he thought he'd point them to this post on Alcademics instead.
So here goes. The below is all courtesy of Mitchell Lagneaux.
There are a few ways one can go about making adult slushies for the masses. You can fill the machine with Slushie mixers, add a bit of booze, or a lot of booze, flip a switch, and an hour later its game on. Nothing wrong with this approach but sometimes you want to achieve a frosty, brain freezing booze bomb with more of a fresh taste, or maybe there isn't a mixer that fits the occasion. I don't know, pick your excuse to not use a margarita mix. Here's a guideline to help you achieve the coolest of cool, the coldest of cold, sweet yet refreshing, adult slushie.
First, if you are looking to serve slushies in a bar or for an event, you want to consider the portion sizes of the beverage. This is going to help you later on with tracking cost. Lets say you want to serve a slushie at 10 ounces. There will probably be at least 2 ounces of liquor in the cocktail. In order to freeze up you are going to need to add quite a bit of water. Think about how much ice you put into a blender when making a frozen drink. You should be filling the blender with ice if you want to get that heavy frozen consistency. So I recommend adding twice the water to booze when assembling your ice palace.
So already we have 2oz booze + 4oz water= 6oz total liquid.
Now it's time to think about the modifiers. Lemon, lime, pineapple, coconut? Sugar, honey, crazy house made syrup? You probably already have the drink in mind that you want to make though. The thing is, the drink is not going to come out tasting the same once frozen as when it's shaken or stirred. The drink is going to taste thin and diluted. So we need to beef up our mixers. Lets take, for example, a Daiquiri.
Some might make a non-slushie Daiquiri like so:
2oz rum 1oz lime .5oz simple syrup.
But when making a Daiquiri that's going to be colder that a witch's teat, we need to add a bit more sugar to the mix. Adjusted, our Daiquiri might look as such:
2oz rum 1oz lime 1oz simple syrup.
Testing Proportions
If you're like me you are going to want to test the drink out before letting the world taste you masterpiece. I've heard of some people weighing ice, or letting a cup of ice melt and seeing how much water it's made up of. The most simple way I can tell how to test out what your frozen beverage is like this.
Make a modified Daiquiri (2oz rum, 1oz lime, 1oz simple). Build this bad boy in a shaker, fill it with as much ice as you can, shake it till the wheels come off, and when you strain the cocktail, measure it. What do you have? Let's say 7oz.
7oz total – 2oz rum – 1.5oz lime – 1oz simple syrup = 2.5 water (dilution)
Lets add another 1.5oz of water to get the drink to the level of water required to freeze. That's brings us to 8.5oz per cocktail. And there you have the serving size. It should taste bit sweet but once frozen the drink should balance itself out. If you feel like it's too sweet or sour make the adjustments as needed.
Now that we have a basic formula for making our slushie we need to have some batched and ready for when it gets low.
Spending time abroad made me appreciate the metric system. Let just remove the "oz" from our recipe and replace it with "mL" and it's that easy.
Refilling Routine
The last, and one of the most important things in my opinion when it comes to serving slushies is the time at which you refill the machine. It typically takes at least an hour for a full machine to freeze the liquid. With that being said, the lower you let the batch go before you add more, the longer it's going to take to get cold.
I recommend topping up the machine when it's about half way down. A trick I've learned is to roll, or rack it once you fill it. This means pour in more of your batch. Next, take the same container you used to fill the machine, fill it back up with the slushie you just topped, and do this 3 or 4 times. This is going to get all of the liquid in the machine to the same temperature, resulting in a faster freeze. Otherwise the new batch will sink to the bottom and the frozen portion will float at the top.
In pot-still distillation we always talk about the cuts: the heads and tails that are discarded (or recycled), and the hearts cut that become the spirit that ends up in the bottle.
But some distillers make another cut between the heart and the tails called the seconds. (Say it with a french pronunciation seh-kuhnndz rather than like seconds on a clock.)
At Privateer Rum in Massachusetts, they make a special rum called The Queen's Share that is a redistillation of just seconds. We'll get to that in a second.
Seconds in Cognac
The first place I heard the term seconds was in Cognac, and frankly I don't know much about it. Luckily for us, Privateer Rum's head distiller Maggie Campbell was trained by Hubert Germain-Robin, a frenchman who has distilled fantastic cognac-style brandies in California since 1984. Campbell was able to fill me in on how this cut of the spirit is used in some cognacs.
To review the process: Cognac is distilled twice in pot stills. The first distillation is the wine distillation. The second one is called the brouillis or low-wines distillation. In cognac, since they only distill for a small part of the year after the grape harvest/fermentation period, they do not make a separate product out of the seconds, but they do often recycle them back into a their next batch of wine bound for distillation, or in the next batch's second distillation.
Note that in single-malt scotch whisky and in some other spirits production they also put the heads/tails back into the first or second distillation, just to get all of the usable alcohol out of it. So this isn't unique to cognac or the seconds. But different brands/categories decide where they "re-pitch" (put into the next distillation batch) the heads, tails, and sometimes seconds. These may be in different places.
Campbell says of seconds in cognac:
In Cognac each distiller has their recipe as to where they re-pitch each one and claim how it changes the flavor of the following distillates.
Some producers redistill the heads and tails and put them into the wine, and others put them into the low wines (brouillis).
They say if it goes into the wine the ABV is significantly raised on the first installation causing the rest of the distillations to be higher in alcohol. Apparently when it goes in the wine there's less concentration of congeners and lighter flavor brandy is made. This is what Martel does.
If the heads and tails go into the brouillis (second distillation) then it makes it richer and deeper. This is what Hennessey does.
Note that doesn't account for the seconds and where they go. Next time I'm in cognac I'm going to research this further.
Seconds in Rum and the Queen's Share
So at Privateer Rum, they do not re-pitch the heads and tails at all so that they don't affect the heart of the distillation or build up.
But the seconds are collected during each distillation and saved. From the explainer sheet:
As the hearts run off the still they become more powerful & flavorful approaching the tails cut. Even once these tails have overpowered the hearts and we’ve made our cut, some of these rich hearts are still intertwined with the bitter tails. At this stage we collect… the ‘seconds’.
These seconds (collected over many runs) are redistilled (a third distillation); the tails of this distillation are discarded; and this special batch of rum is then aged separately.
This is what made up the release of the first single barrel of Privateer's Queen's Share. It was aged 3 years and bottled.
If you've read this far, I've got bad news for you: There wasn't very much of it and it's probably long-since sold out.
If you are able to add an aquarium pump to the mix, you can make clear ice from the bottom up without any cloudy parts at the end; a method that mimics how professional ice block machines work.
Today we'll talk about how to make clear ice with an aquarium pump and no cooler, and how this same method allows us to freeze objects in an ice block also without an insulated cooler.
While I've always favored the non-electricity Directional Freezing method, Alcademics reader fang2415 prefers to use an aquarium pump without (much) insulation. This takes up little less space in the freezer, and it seems like a much faster method than with insulation – as below, he says he gets a 4-liter ice block every day!
In short, fang2415 places an aquarium pump at the top of an uninsulated container of water in the freezer, just barely insulating the top of the container with bubble wrap to help prevent it freezing over. He then found that this also works to freeze objects inside ice blocks.
He describes the method:
The method is really simple: basically it's the same thing I now do to make most of my ice using an aquarium pump in a plain Tupperware-style plastic 5L container, but this time I threw a bottle inside the container and used tinfoil as a cover since the bottle was too tall for the lid to it.
I've been making all my ice this way recently, and every day I get a big beautiful 4-liter-or-so block of ice. The only real annoyance is cutting the pump out.
I filled the container up to about .5 inch from the top and stuck my 150 L/H aquarium pump to the side just below the surface. Usually I aim the pump so that the outlet goes across the middle of the surface, but this time I kept it to one side so that the jet went around the side of the bottle's neck.
I've found that insulation barely matters with the pump method, although I usually cover the top with two layers of bubble wrap to reduce freezing at the top. Tying the bubble wrap with string works just fine; it just means that you need to knock the top ice-collar off at the end.
After chiseling the pump out (which is probably the most difficult part of the process), I had a bottle with the top conveniently exposed inside a large squarish block of clear ice.
He then chisels out the aquarium pump and cuts or runs water over the outside edges to smooth out the block of ice and make the bottle label more legible.
Thanks once again to dedicated ice nerd fang2415 for not only doing the experiments, but for taking pictures and sharing with the Alcademics audience!
Throughout the year I post new drink books to Alcademics, because I love drinking and books. Below is all of them put together so that you can make your holiday wish list for yourself or see them all together to pick presents for friends and family.
Know of a book I missed? Let me know and I'll add it.
Culture and Fun
You Suck At Drinking: Being a Complete Guide to Drinking for Any and All Situations in Your Life, Including But Not Limited to Office Holiday Parties, Weddings, Breakups and Other Sad Times, Outdoor Chores Like Deck-building, and While in Public, Legally and Illegally By Matthew Latkiewicz
Cocktails of the Movies: An Illustrated Guide to Cinematic Mixology by Will Francis , Stacey Marsh
Imbibe! From Absinthe Cocktail to Whiskey Smash, a Salute in Stories and Drinks to “Professor” Jerry Thomas, Pioneer of the American Bar (Updated and Revised Edition) By David Wondrich
Contraband Cocktails: How America Drank When It Wasn't Supposed To by Paul Dickson
Narrative Cocktail Books
The Cocktail Chronicles: Navigating the Cocktail Renaissance with Jigger, Shaker & Glass by Paul Clarke
Ten Cocktails: The Art of Convivial Drinking by Alice Lascelles
Cocktails from Specific Bars
The Dead Rabbit Drinks Manual: Secret Recipes and Barroom Tales from Two Belfast Boys Who Conquered the Cocktail World by Sean Muldoon, Jack McGarry, Ben Schaffer
Experimental Cocktail Club: Paris, London & New York by Romée de Goriainoff, Pierre-Charles Cros, Olivier Bon, Xavier Padavoni
Cuban Cocktails: 100 Classic and Modern Drinks by Ravi DeRossi, Jane Danger, Alla Lapushchik
Tujague's Cookbook: Creole Recipes and Lore in the New Orleans Grand Tradition by Poppy Tooker
I wrote a story for Popular Science on the science of barrel aging. The story was inspired by a trip to The Glenlivet where I tasted a 50-year-old whisky without any smoky qualities – but 50 years ago this and most whisky would have been at least lightly peated.
So I went into the article specifically looking for what happens with the smoke, but ended up writing about wood interactions as well.
To do the story, I read several wood science articles sent to me by Diageo whisky ambassador/smart-guy Ewan Morgan, spoke with Dr Bill Lumsden from Glenmorangie, interviewed Bryan Davis from Lost Spirits, and illustrated the story with a chart from Lew Bryson's excellent book Tasting Whisky.
Hopefully I didn't get anything wrong. Read it here.
I've done a few years' worth of ice experiments here on Alcademics, and sometimes bartenders contact me on how to solve ice problems. (That should be my new reality show: Ice Whisperer.)
Here is the index to the ice experiments on Alcademics, where you'll find how to make clear ice blocks, clear ice cubes, clear ice spheres, and many other ice successes and failures.
One bartender was curious about some ways to present bottles in ice yet still be able to read the labels. I presented a few ideas and have probably found a solution that works for the bar (that I'll share when it's open), but this method is something that does work but wasn't a great fit for that particular program.
Anyway, enough with the backstory. Look at this cool spinning bottle!
This technique uses directional freezing (freezing inside an insulated cooler with the top off so that it only freezes from the top-down), with the bottle raised high so that it's in the clear part of the ice block.
Method for Freezing a Bottle in a Clear Ice Block:
1. Fill a picnic cooler with water.
2. Place some sort of stand on the bottom of the cooler. I used a plastic box in one experiment and an oversized metal piece that looks like a napkin ring in another. Anything that lets water move through it is ideal.
3. Place the bottle on its side, diagonally across the cooler. Note that very tall bottles may not fit in your cooler. Fill the cooler with water to an inch or two above the bottle.
4. Leave the top off the cooler and let it freeze for a couple of days.
5. When the block freezes either all the way through to the bottom of the cooler, or (better year) just to the point at which it starts to become cloudy at the bottom part of the block, remove it from the freezer. Tip over the cooler and let the block slide out.
6. Let the ice slowly warm to temper it, then use an ice pick (the three-prong one is my preferred tool for this task) to scrape off the cloudy section. You can break off the cloudy ice in any creative way you want. As you can see, for the Tanqueray I did a super cool nugget-style chipping, while for the Plymouth Sloe Gin I did a scrape on only one side so that it's super flat on the front surface.
As you can see, the top of the bottle is at the corner of the block, so you can easily open it and pour from the bottle still.
Example One
Looking down on the cooler with a big napkin ring at the bottom on which the bottle will sit.
The bottle sits on the stand with enough water to cover it.
From the bottom: Now to chip off that cloudy layer!
Ta Da!
Example Two
Frozen block with bottle. You can see the yellow of the plastic open box I sat the bottle on.
In a post for PopularScience.com I wrote about a technology being employed to toast wine and now whiskey barrels with infrared light. 
