ok, I must have skipped over this. my usual curiosity. how does this cause the wine to become more sweet? when the sugar crystals crystalize does this somehow cause the yeast to not be able to consume them? questioning from a brewer's stand point. usually the fermenting process is controlled as in it is stopped early (one way being temperature as in dropping it enough to kill the yeast before they're done), adding more sugar when the yeast is killed or causing them to go dormant (this way usually causes carbonation if they aren't killed), or simply having more sugar than the yeast can eat or tolerate for long periods of time.
Originally Posted by JustMeCLTXGG
I'm going to plagiarize wiki, since someone else has already had the decency to write this up for me.
Icewine Entry from Wiki:
Ice wine (or icewine; German Eiswein) is a type of dessert wine produced from grapes that have been frozen while still on the vine. The sugars and other dissolved solids do not freeze, but the water does, allowing a more concentrated grape must to be pressed from the frozen grapes, resulting in a smaller amount of more concentrated, very sweet wine. With ice wines, the freezing happens before the fermentation, not afterwards. Unlike the grapes from which other dessert wines are made, such as Sauternes, Tokaji, or Trockenbeerenauslese, ice wine grapes should not be affected by Botrytis cinerea or noble rot, at least not to any great degree. Only healthy grapes keep in good shape until the opportunity arises for an ice wine harvest, which in extreme cases can occur after the New Year, on a northern hemisphere calendar. This gives ice wine its characteristic refreshing sweetness balanced by high acidity. When the grapes are free of Botrytis, they are said to come in "clean".
Ice wine production is risky (the frost may not come at all before the grapes rot or are otherwise lost) and requires the availability of a large enough labour force to pick the whole crop within a few hours, at a moment's notice, on the first morning that is cold enough. This results in relatively small amounts of ice wine being made world-wide, making ice wines generally quite expensive.
Ice wine production is obviously limited to that minority of the world's wine-growing regions where the necessary cold temperatures can be expected to be reached with some regularity. Canada and Germany are the world's largest producers of ice wines. About 75 percent of the ice wine in Canada comes from Ontario.[1]
*EDIT*
And on a personal note, I've picked up two bottles of my favorite kind. One is as a gift for a local provider who was kind enough to answer some questions about the area, and do's and don'ts. The other - I'm trying to find someone to drink it with.