A

Ice wine, or Eiswein as the Germans call it, is the product of frozen grapes.  A small portion of the vineyard is left unpicked during the fall harvest those grapes are left on the vine until the mercury drops to at least -7°C.  At this temperature, the sugar-rich juice begins to freeze.  If the grapes are picked in their frozen state and pressed while they are as hard as marbles, the small amount of juice recovered is intensely sweet and high in acidity.  The amber dessert wine made from this juice is an ambrosia fit for Dionysus¹ himself - very sweet, it combines savours of peach and apricot.

B

The discovery of ice wine, like most epicurean breakthroughs was accidental.  In 1794, wine producers in the German duchy of Franconia made virtue of necessity by pressing juice from frozen grapes.  They were amazed by an abnormally high concentration of sugars and acids which, until then, had been achieved only by drying the grapes on straw mats before pressing or by the effects of Botrytis cinerea, a disease known as 'root rot'.  Botrytis cinerea afflicts grapes in autumn, usually in regions where there is early morning fog and humid, sunny afternoons.  A mushroom-like fungus attaches itself to the berries, punctures their skins and allows the juice to evaporate.  To many, the result is sheer ambrosia.  The world's great dessert wines, such as Sauternes, Riesling and Tokay Aszú Essencia, are made from grapes afflicted by this benign disease.

C

It was not until the mid-19^th century in the Rheingau region of northwestern Germany that winegrowers made conscious efforts to produce ice wine on a regular basis.  But they found they could not make it every year since the subzero cold spell must last several days to ensure that the berries remain frozen solid during picking and the pressing process, which alone can take up to three days or longer.  Grapes are 80 percent water; when this water is frozen and driven off under pressure and shards of ice, the resulting juice is wonderfully sweet.  If the ice melts during a sudden thaw, the sugar in each berry is diluted.

D

Not all grapes are suitable for ice wine.  Only the thick-skinned, late-maturing varieties such as Riesling and Vidal can resist such predators as grey rot, powdery mildew, unseasonable warmth, wind, rain and the variety of fauna craving a sweet meal.  Leaving grapes on the vine once they have ripened is an enormous gamble.  If birds and animals do not get them, mildew and rot or a sudden storm might.  So growers reserve only a small portion of their Vidal or Riesling grapes for ice wine, a couple of hectares of views at most. 

E

To ensure the right temperature is maintained, in Germany the pickers must be out well before dawn to harvest the grapes.  A vineyard left for ice wine is a sorry sight.  The mesh-covered vines are denuded of leaves and the grapes are brown and shrivelled, dangling like tiny bats from the frozen canes.  The stems of the grape clusters are dry and brittle.  A strong wind or an ice storm could easily knock the fruit to the ground.  A twist of the wrist is all that is needed to pick them, but when the wind howls through the vineyard, driving the snow before it and the wind chill factor can make a temperature of -10° seem like -40°, harvesting ice wine grapes becomes a decidedly uncomfortable business.  Pickers fortified with tea and brandy, brave the elements for two hours at a time before rushing back to the winery to warm up.

F

Once the tractor delivers the precious boxes of grapes to the winery, the really hard work begins.  Since the berries must remain frozen, the pressing is done either outdoors or inside the winery with the doors left open.  The presses have to be worked slowly otherwise the bunches will turn to a solid block of ice yielding nothing.  Some producers throw rice husks into the press to pierce the skins of the grapes and create channels for the juice to flow through the mass of ice.  Sometimes it takes two or three hours before the first drop of juice appears.

G

A kilogram of unfrozen grapes normally produces sufficient juice to ferment² into one bottle of wine.  Depending on the degree of dehydration caused by wind and winter sunshine, the juice from a kilogram of ice wine grapes produces one-fifth of that amount or less. The longer the grapes hang on the vine, the less juice there is.  So grapes harvested during a cold snap in December will yield more ice wine than if they are picked in February.  The oily juice, once extracted from the marble-hard berries, is allowed to settle for three or four days.  It is then clarified of dust and debris by 'racking' from one tank to another.  A special yeast is added to activate fermentation in the stainless steel tanks since the colourless liquid is too cold to ferment on its own.  Because of the high sugar content, the fermentation can take several months.  But when the wine is finally bottled, it has the capacity to age for a decade or more.

H

While Germany may be recognised as the home of ice wine, its winemakers cannot produce it every year.  Canadian winemakers can and are slowly becoming known for this expensive rarity as the home-grown product garners medals at international wine competitions.  Klaus Reif of the Reif Winery at Niagara-on-the-Lake has produced ice wine in both countries.  While studying oenology, the science of winemaking, he worked at a government winery in Neustadt in the West German state of Rheinland-Pfalz.  In 1983 he made his first Canadian ice wine from Riesling grapes.  Four years later he made ice wine from Vidal grapes grown in his uncle's vineyard at Niagara-on-the-Lake. "The juice comes out like honey here" says Reif, "but in Germany it has the consistency of ordinary wine".