It’s a question as old as alcohol itself: “The aesthetics of this drink are pleasing, but the cloudiness of the ice is juxtaposed to the refractive index of the crystal vessel.” I’m fairly certain those were the words used.
Historical interpretations aside, the question has been asked before. “How do I make clear ice?” I know this because a quick internet search revealed this dilemma to be ubiquitous. It is the natural progression in drinking: Discovery –> Refining tastes –> Enhancing the function of vessels –> Presentation/Aesthetics. Each stage in the discovery is dependent on its predecessor. Alcohol must be discovered before one can develop personal taste. A refinement of taste is required before the functionally enhancing aspects of the vessel can be appreciated. And ultimately the primary and secondary purposes of alcohol, namely its inebriating and tasty qualities, must be acquired before the ultimate tertiary properties of aesthetics can be applied.
As an experienced drinker (or depending on who you ask: functioning alcoholic), I have long since advanced upon this hierarchy of needs. Having mastered the art of garnishes, and having acquired a respectable quantity of crystal bar-ware, one point of concern remained.
So, as with all of life’s great mysteries, I immediately started a journey through the Internet. The Holy Oracle, i.e. Google, referred me to numerous blogs and forums which attempted to address this glaring deficiency in mixology.
As a side note, I wanted to jest a moment on the nature of Internet forums. After the golden age of the Internet’s nubile novelty and innocence, its inevitable ubiquity brought with it the general trash of humanity. Trolls. But after the tipping point, when the Internet became universal, when more forums entered existence than could be discovered in a lifetime, well, trolls tend to gravitate towards the larger masses of Internet presences to achieve maximum effect. That is, the more esoteric the discussion, the more decreased the likelihood that a troll will crawl out of the filth to infect the core of knowledge. While I only found limited information on the way of ice and its translucency, there definitely weren’t any trolls in those discussions.
But back to the problem at hand. I compiled a list of repetitious advice:
- Use distilled water
- Freeze slowly
- Use hot water
- Use boiled water
- Use twice-boiled water
- Freeze in large blocks
After thorough testing, most of these were either nonsense or had no measurable impact. I will elaborate:
- Use distilled water More importantly, use relatively clean water. The focus here is to reduce dissolved impurities, so the quality of local tap water is paramount. If it’s very bad, then yes, I suppose distilled would net obvious improvements.
- Freeze slowly Nonsense, and not worth the effort.
- Use hot water Bingo! Hot water of course holds fewer dissolved gasses, which are the primary cause of cloudiness.
- Use boiled water The temperature hits a point of diminishing returns. Any variations above say 130 degrees were negligible. And if the water is too hot it’s just dangerous to handle, and it can melt plastic.
- Use twice-boiled water I’m not sure what the logic on this one is. Maybe it purges any gasses not purged the first time? I’m sure someone with more knowledge in chemistry/physics could explain this theory, but in practice it’s negligible.
- Freeze in large blocks Also bingo! The volume allows the trapped air to congregate as the ice freezes inward, leaving the periphery devoid of air. [Edit 2017.4.28: Leave the water sit out for 20 minutes before placing in freezer. This will allow it to offgas more before ice traps the air, without allowing so much time that the cooling water absorbs more gas]
Conclusion: reduce the total amount of dissolved gas by heating the water, then freeze the water in a volume large enough that the amount of remaining dissolved gas isn’t noticeable at the edge of the resultant ice. This second part–the volume–is open to experimentation. I’ve tried various volumes and container shapes with wildly different and inconsistent results. I will say that long and flat Tupperware seems to work better. Maybe it’s the increased surface area of exposed water.
One problem remains–how to separate the clear ice from the cloudy. I found the solution lay, as it often does, in violence and needless waste. A hammer and old steak knife chipped the ice into manageable chunks, and a running faucet of hot water could melt the cloudy ice off the clear. Is the latter wasteful? Yes. But…the cost of perfection always leaves casualties in its wake. Besides, look at this:
Also, the clear ice melts slower, so bonus. Your guests might not appreciate it, but there will be no argument on your pretentiousness. Toast yourself on having achieved drinking self-actualization.