Washington is blessed with the rare climate conditions needed to produce ice wines, particularly in the vineyards in the Eastern half of the state. This week's cold snap, with temperatures at night falling in the low teens, has allowed a number of Washington wineries to gather the frozen and very ripe grapes required to make ice wine.
A German tradition, ice wine (eiswein to the Germans) is made when the frost hits the vines at just the right time to freeze the ripe, fully mature grapes. Because water remains frozen longer than the sweet, intensely flavorful juice of the mature grapes, gentle, careful pressing releases a few drops of concentrated juice. That concentration also means that it takes more grapes to make a single bottle of wine, which means the wine is more expensive— one reason the sweet dessert style wines are traditionally sold in half-size bottles. The harvest usually takes place in the pre-dawn hours, once the very ripe grapes have frozen, but before they have time to thaw. The marble-like grapes are pressed while still frozen.
Ice wine is always a bit of a gamble for winemakers; they don't know when, or even if, the ripe grapes will freeze, but they must leave them on the vine in case they are lucky enough to be blessed with temperature drop in the 14 to 19 degrees F. range required to completely freeze the grapes. And they must protect the grapes from legions of hungry birds, which usually necessitates covering the fruited vines with bird netting; all in aid of a gamble which might not pay off. If you click the image above of ice-covered grapes clinging to frosted vines, you can see a video from Covey Run about ice wine.
Ice wine is by no means a modern invention. There are references in Latin texts that suggest some grapes were deliberately harvested after the frost; it isn't clear whether the grapes were merely a late-harvest, or truly frozen. Certainly by the nineteenth century, ice wine was known to German vintners.
Although Canada is the largest producer of ice swine, there are a number of Washington wineries with successful ice wines in their repertoire. Chateau Ste. Michelle produced a 2006 Riesling ice wine. Columbia Winery also makes a Riesling ice wine. Although Riesling is the traditional varietal favorite for ice wine, other grape varieties are also used. Brian Carter, of Apex Cellars, uses Gewürztraminer as the base for his ice wine. Covey Run, producing occasional ice wines since 1986, has made ice wines from Semillon as well as Riesling and Chenin Blanc grapes. Kiona has a 2006 Chenin Blanc ice wine. Amavi produces ice wine from Semillon grapes. Terra Blanc produces Chenin blanc and Riesling ice wines. A few Canadian wineries are experimenting with very non-traditional red ice wines, using Cabernet Franc, Merlot, or Pinot Noir grapes. Lake Crest Winery makes a Syrah ice wine.
This year, early in the 2 F. morning chill on December 16, workers at Horse Heaven Hills vineyard began harvesting about seven tons of frozen Riesling grapes, according to Kevin Corliss, director of operations for Chateau Ste. Michelle winery. The particular vines are from the same block used to produce Chateau Ste. Michelle's highly rated Single Berry Select wine. Winemaker Wendy Stuckey said that "the grapes sounded like bullets when they hit the hopper." The grapes produced about 200 gallons of the extremely sweet, rich juice. This year's harvest was the seventh successful ice wine harvest for Chateau Ste. Michelle. With luck, we should be able to purchase the wine in 2010.After a week of being snow-bound, I'm looking forward to a bottle as my reward. In fact, given the way that past vintages have increased in price, and improved with age, this may well be a wine worth buying and storing for very special occasions.