Feeding the Ice Monkey

Preamble…

Once you’ve frothed egg white drinks with Kold Draft cubes, ice-maker ice cubes will just not cut it. You can hear and feel them start to shatter in the tins well before the egg white reaches the desired semi-meringe state. Once you’ve chilled an Old Fashioned or Improved Whiskey Cocktail using a clear hand-cut block of ice the size of your fist, anything else will seem inadequate and you might as well just dilute your drink with ice water.

Yes, I have developed an ice fetish. I suppose given my propensity to take anything I do to an extreme it was only a matter of time before I found myself with an “ice monkey” on my back. The question now is what’s a home mixologist to do? Well, I did some experimenting and the good news is that it’s possible to feed the ice-monkey without a lot of fuss.

Graduating to the hard stuff…

First off I want to say I have never been able to make really clear ice cubes using any of the commonly published home techniques: distilled water, boiling water, boiling it twice, letting it stand, filtering, etc. Nope: the cubes were always cloudy. And I had awful problems with silicone trays, four of them which quickly developed off-odors rendering the ice unsuable. So, last summer when I found myself living in a house with a decent ice maker, I abandoned trays altogether, trading I suppose some quality for convenience. That however was before I started working on the LCL project, before I was exposed to Kold Draft cubes and hand-cut ice blocks. Once I got a taste of those, I quickly graduated to needing the hard stuff. Damn! I was hooked.

Recap: what makes ice cloudy?

My understanding is that home-made ice comes out cloudy for two reasons: dissolved gases and any tiny amounts of suspended mineral particulates in the water. As each cube freezes these tend to become concentrated and trapped in the unfrozen water at the center of each cube. This becomes the cloudy “heart” of each finished cube.

Commercial ice is clear (or clearer) then because it starts with water that’s mostly free of suspended mineral particulates and because it’s then frozen using mechanisms which avoid trapping of gases as they come out of solution (*).

*- There is a bit of a paradox here. Normally, the colder the liquid, the more gas can be dissolved in it. My best guess is that the phase change from liquid to solid affects the ability for gases to remain dissolved, driving gasses from the ice as it forms into the remaining liquid at the center of each cube. If someone knows the actual answer to this, I’d appreciate learning it.

An observation…

While I had odor problems with my silicone trays, I did make the following useful observation: the cubes at the edges of each tray were clearer than the cubes at the center. I speculated this was because the cubes in the center were more insulated from the cold than the cubes at the edges. The edge cubes froze faster (so that dissolved gas didn’t get a chance to concentrate) while the center cubes froze more slowly (resulting in typical cloudy centers). This made me wonder what would happen if I didn’t use a tray at all, if I just tried freezing the water in large rectangular mold to make large blocks?

Experiments…

The first blocks I made were created using a low rectangular plastic “to go” food containers that a lot of Chinese restaurants are now using in the Bay Area. Before freezing, I filled them with water and let them sit at room temperature for a couple of hours to get as much dissolved gas out as possible, (Note: this was standard procedure for all other experiments described here.) These blocks were mostly clear and my supposition is that the large overall surface area of the mold resulted in the top of the block remaining unfrozen long enough for most of the dissolved gases to escape. The blocks were to big to be used as is needed to be broken up by cracking. This left me with lot of smaller pieces and fragments which weren’t very useful for shaking or “on the rocks” style drinks as they melted too fast. I also couldn’t reliably obtain single pieces sized appropriately for a rocks glass.

My next experiment involved using small Tupperware-style food containers. My thought was that if I could find a mold large enough to freeze w/o trapping gas bubbles but small enough to yield a single usable block, I’d be in business. I found some Rubbermaid containers from the “Easy Find Lids” series which seemed like they might do. These yielded blocks which weren’t very clear and which were highly fractured. Quite different than the results I got with the “to go” food containers. Why?

Rubermaid Ice

After some pondering, I realized I had stumbled upon something very important: if the mold is too stiff, the resulting ice will be fractured as a result of expansion that occurs during freezing. The “to go” food containers had relatively thin walls and flexed outward as the water froze. The Rubbermaid containers on the other hand were made from much thicker plastic. Without some flex, the freezing water has no where to go so it breaks up as it nears the end of the freezing cycle Despite the fractures, the resulting blocks were solid enough to use for an Old Fashioned where they in fact worked very well. However, shaking them up in tins resulted in immediate shattering and the creation of lots of crushed ice.

Rubermaid Ice Block in Old Fashioned

A rapid improvement…

Armed with the additional data from the last experiment, I decided to try using thin-walled disposable plastic cups. My intuition is that these would flex when the ice formed thereby eliminating the fracturing problems. I found some 6 oz clear plastic Dixiecups and filled them with 4 oz of water each. The results were small “plugs” with few or no large fractures and relatively small cloudy “heart.” Here’s what they look like:

Dixiecup Ice Plugs
Dixecup Ice Plug Details

The first thing I tried was to make an Old Fashioned. The plugs just fit into my preferred OF glasses along with a 2 oz drink. I didn’t make a precise measurement but I’d say that about 60% – 70% of the block remained after the cocktail was finished, about 30 minutes later. A very satisfying result.

Next up, I decided to use crack a few plugs in half (which they do readily) and use in my tins for shaking. The ice from my freezer’s ice maker (which comes out in small crescents rather than cubes) more or less disintegrates during a hard shake, leaving a lot of small bits of ice in the tin afterwards. Cracked ice plugs more or less remained intact during a hard shake (I made an egg white cocktail so I really worked this ice hard). Here’s a photo of what I found in the tins after I was done:

Spent Ice Plugs

Conclusions…

Overall I think I’ve hit upon a reasonable method for keeping my ice monkey happy (short of buying it it’s own Kold Draft machine or going into ice rehab). It’s easy to fill the small plastic cups, let them sit about for a couple of hours and then freeze ’em up. Oh, and the ice comes out pretty easily, by the way. Do note that the cups eventually develop cracks as a result of repeated expansion of the freezing water. But because they are cheap, replacement isn’t a big deal.

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