Since this was a fine ($8) Wisconsin wine (Prairie Fume, Wollersheim - #5 of the top 100 wines east of the Rockies in 2004), we decided to thaw it and finish the bottle. Imagine my puzzlement when, upon thawing, the wine bottle exhibited a fairly substantial precipitate of crystals on the bottom. After receiving reassurances from my wife that she had not slipped any surprises into the wine, I tried to decant the supernatant, but the crystals spilled into the glass and I drank them. The flavor was o.k. and I appear to have suffered no ill effects.
Googling this subject today, I found the identity of the crystals:
Chances are that freezing and thawing won't seriously damage the wine itself, although on general principles I wouldn't try it with a treasured rarity. Near-freezing temperatures may precipitate out some of the wine's natural acidity in the form of insoluble tartrate crystals, but most authorities argue that this doesn't perceptibly affect the flavor of the wine.Tangentially related is "ice wine" -
"... 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, so the result is a concentrated, often very sweet wine. The most famous (and expensive) ice wines are German Eiswein and Canadian ice wine..."There were a number of discussion threads in which people wrongly proclaimed that freezing wine was impossible because of the alcohol content. The correct response (from Wikianswers) is that the freezing point of pure alcohol is -173 F, but wine with low alcohol content can freeze with temps in the low teens Fahrenheit.
Which serves as an introduction to my next query. I seem to remember reading somewhere that during Napoleon's winter campaign to Russia the wine froze (as of course did the horses and the soldiers), and that from the frozen wine bottles a purer alcohol could be harvested. Googling that question brought me to this comment at a "home brew" thread:
"Grandfather would make seasonal wines. Whatever fruit was in season... He then had a rather unique way to turn the wine into brandy (cognac). He would transfer the wine to a plastic jug and put it in the freezer. The water in the wine would freeze, but the alcohol would not. He then transferred this to bottles and capped them. The result being that we had natural flavored brandy of all types..."What's being described there seems to be a form of cold distillation. That led me to a very interesting site entitled "Alcoholic Drinks of the Middle Ages."
Another method, known as fractional crystalization, is done by inverting the process and freezing the beverage instead of boiling it. This works for very similar reasons to that of normal heat distillation, namely, the differential in freezing points of the two liquids involved. Water freezes at a temperature of 0 C, while ethyl alcohol does not freeze until reaching -114 C. This allows the water to be frozen out of the liquid, leaving behind the ethyl alcohol, as well as the other alcohols and esters. This produces a drink of a rather different character from heat distillation, as it contains everything except water, while heat distilled beverages leave everything behind except alcohol.The website also has a nice table of freezing points for different alcohol concentrations, explanations of the differences between brandies, whiskies, and cognacs, and an introduction to the distilling of liquor in medieval times, citing recipes in "Delightes for Ladies" -
"...a book of recipes and household hints for women, written... in 1602. Its full title is Delightes for ladies: to adorn their persons, tables, closets, and distillatories with beauties, banquets, perfumes and waters. A successful book in its day, some of the recipes have survived to be in relatively common use even 400 years later, in particular the various mixed alcoholic beverages."Ladies of the 1600s had... "distillatories" ??
At this point I'll have to stop exploring the subject because I'm getting way out of my depth. Perhaps Morchava will know of something in her library of medieval literature, or maybe Gail over at Scribal Terror can come up with more information or images of ladies' distillatories.
And all this because we left a bottle of wine on the screen porch overnight...
Addendum: here's an illustration of a medieval still that Gail found -
