Wine is a mixture of water, alcohol, sugars, and other substances. Dissolving stuff in water will lower its freezing temperature. Even the alcohol by itself will have a lower freezing temperature than water by itself, but the mixture may have a lower freezing temperature than either (or it may be in between, particularly if the concentration of alcohol in the wine is low, as it is for most wines. It may be the sugars and other stuff which do more to lower the freezing temperature).
The key point is that as the water in the wine starts to freeze, it leaves behind a solution with a still higher concentration of sugar and alcohol, and hence an even lower freezing point. A typical freezer may be cold enough to get some ice to form, but not to get ice to form out of that more concentrated solution. So what youíre left with is slush- little ice crystals surrounded by a concentrated solution.
Wine should freeze solid if you get it cold enough. This may not be possible in your freezer -- dry ice (frozen carbon dioxide -- very cold!) should do the trick though. Be very careful handling dry ice -- it can cause serious burns on your hands. Wear thick gloves and donít get them wet!
Tom (and mike)
(republished on 07/25/06)