#1014 1794 · Franconia winegrowers, Würzburg region, Germany · Winemaking

German winegrowers pressed a frost-ruined harvest anyway and invented a luxury wine

问题

An unexpected hard frost hit unharvested grapes before picking, threatening growers with a worthless, frozen-solid crop

背景

In the Franconia wine region near Würzburg, an unexpected frost struck before the grape harvest was finished, freezing the fruit still hanging on the vine. By ordinary winemaking standards the crop was ruined: frozen grapes are not something a vintner presses, and the season's income from that fruit looked like a total loss. Rather than abandon the frozen vines entirely, the growers picked what was left anyway, unwilling to walk away from a harvest even in its damaged state.

When they pressed the frozen grapes, they got back only a small trickle of juice, but it was startlingly different from anything a normal harvest produced: intensely sweet, deeply concentrated, and unlike the thinner wine an unfrozen crop would have made. The reason was mechanical, not mystical. Water freezes at a higher temperature than the sugars and other dissolved solids in grape juice, so when the frozen fruit was pressed, the ice crystals stayed largely behind in the press while the concentrated, sugar-rich liquid ran out. Growers began deliberately waiting for a hard freeze in later vintages to reproduce the effect on purpose.

换别人会怎么做

The standard response to a frost-damaged crop is to write off the loss, since frozen, damaged fruit looks unusable by every normal winemaking standard, and pressing it seems like wasted effort on a harvest already lost.

他们看到了什么

Everyone assumed frozen grapes were ruined. The frost split the fruit into frozen water and unfrozen sugar, and pressing kept the valuable part, discarding the ice. Damage had already done the filtering, for free.

那一手

Instead of discarding grapes damaged by an out-of-season frost, they pressed them anyway and let the freezing itself do the processing work: because ice forms before sugar solidifies, pressing frozen fruit naturally separated water from the concentrated juice, turning a weather disaster into a way to make a more valuable wine than the undamaged crop would have produced.

为什么管用

Because water and dissolved sugar freeze at different temperatures, a hard frost performs a rough but effective separation before any equipment gets involved, concentrating sugars and flavor compounds into a small volume of juice at essentially zero processing cost. The resulting scarcity, a tiny yield per vine, also supports a premium price, so the same frost that destroyed volume created the product's exclusivity.

值了多少

Eiswein became one of Germany's most prized dessert wines, later formalized by Dr. Hans Georg Ambrosi as a protected Prädikat category.

什么时候会失灵

It only works if the freeze happens after the grapes have developed full ripeness but before rot sets in, an early or excessively hard frost can kill the fruit outright with nothing to press. It also depends on a climate with reliably cold nights in a narrow window each year, growers who can't count on that timing are gambling an entire crop on weather they can't control.

后来呢

Ice wine production spread to Austria, Canada and other cold-climate wine regions, and growers now deliberately leave a portion of the crop on the vine each year, hoping for the very frost that once looked like nothing but loss.

资料来源

[1]What's the story with eiswein?Wine Spectator, 2010winespectator.com