The Modern Rogue invited mixologist Nick Fisher from Cocktail Chemistry (previously) to demonstrate his method for making crystal clear ice with regular tap water. The key is directional freezing, which uses gravity to pull all the sediment and gasses to the bottom. Nick used an inexpensive cooler to show how it’s done.
So what we have here is this cooler and …I’ve removed the top of it here right so there’s no lid, I’ve pulled it right off and what that leaves us with is this. This device is insulated on all sides except for the top and that’s going to force the freezing process to happen from the top down. Because this part is exposed and so the freezing is going to happen here first and that is important because all of the impurities and the trapped gasses form at the end of the freezing process. So we’re effectively pushing all that impurity and cloudiness down to the bottom
via Boing Boing