going to break either consistently or almost never. Quality is not an indicator of chillability. At a pro bar, chilling glasses with LN means I don’t need a dedicated glass-chilling freezer. It may be easier at home to chill your glasses in the freezer, but at the bar, LN helps us maximize our back-of-house space. DRY ICE Dry ice is solidified carbon dioxide. It’s called dry because carbon dioxide doesn’t exist as a liquid at normal atmospheric pressure; it turns directly from a solid to a gas through a process called sublimation. Dry ice appears to be the friendlier cryogen— it’s easier to get, less likely to give you cryogenic burns, and, as a solid, easier to handle than liquid nitrogen. Furthermore, even though dry ice is much warmer than liquid nitrogen—a balmy −109.3°F (−78.5°C)—don’t let that warmer temperature fool you. Pound for pound, dry ice has almost twice the cooling power of liquid nitrogen, because it takes a lot of energy to turn CO directly from a solid into a gas (136.5 calories per gram), whereas liquid nitrogen needs only a measly 47.5 calories per gram to vaporize. 2
As dry ice chills, it lightly carbonates whatever liquid it is in, which is why I primarily use dry ice at events to prechill drinks that I’m about to carbonate. The problem with dry ice: it is hard to use its cooling power effectively. Unlike liquid nitrogen, which can surround and coat solids or mix with other liquids to create a large surface area for effective rapid chilling, dry ice is a solid, so it is hard to get it to chill drinks rapidly. Drop a chunk of dry ice into a glass of liquid. Initially you get bubbling and foaming and a nice carbon dioxide fog. Pretty soon, however, the liquid calms down and your chilling rate radically slows. Look at the liquid: there’s still dry ice in there, but a layer of liquid has frozen over the dry ice, insulating it. Beat on the nugget with something to break off the frozen layer and the chilling speeds up again. Safety rule: never use dry ice to carbonate drinks in a sealed container unless you are an engineer qualified to design pressure vessels with overpressure safety valves. Search the Internet for pictures of unsuspecting boneheads who dropped dry ice into a soda bottle and sealed it, just to have it blow up in their hands. On second thought, don’t. An obscure but enjoyable use for dry ice is to keep large batches of drinks chilled at events. You need an immersion circulator (a device with a heater that keeps liquids at very accurate temperatures) that can be set below freezing, a large plastic tub, a bunch of cheap vodka, and some dry ice. You fill the tub with the vodka, which has a very low freezing point, set up the immersion circulator in it, and then add dry ice. A pump in the circulator will keep the vodka moving around; it stirs the bath for
